Physics
New submissions
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New submissions for Wed, 1 May 24
- [1] arXiv:2404.18936 [pdf, ps, other]
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Title: On spatial electron-photon entanglementComments: 10 pages, 2 figuresSubjects: General Physics (physics.gen-ph)
Free electron beams and their quantum coupling with photons is attracting a rising interest due to the basic questions it addresses and the cutting-edge technology these particles are involved in, such as microscopy, spectroscopy, and quantum computation. This work investigates theoretically the concept of electron-photon coupling in the spatial domain. Their interaction is discussed as a thought experiment of spontaneous photon emission from a dual-path free-electron (free-e) beam. We discuss a retro-causal paradox that may emerge from naively extending perceptions of single-path e-photon coupling to transversely separated paths, and its resolution through the physics of two-particle interference. The precise spatial control of electrons and photons within e-microscopes enables manipulation of their respective states, thus, such instruments can harness position-encoded free-e qubits for novel quantum sensing and the transfer of quantum information.
- [2] arXiv:2404.18937 [pdf, ps, other]
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Title: Unification of the Gauge TheoriesAuthors: Abolfazl JafariComments: 8 pages, 0 figuresSubjects: General Physics (physics.gen-ph)
We take the Christoffel coefficients as an operator and introduce new mappings for quaternionic products to reach the theory of electrodynamics in general spacetime. With the help of the directional operator of the covariant derivative, we generalize the quaternioic mechanism to the theory of gravity and show that the Einstein equation has the freedom to choose the constant term in agreement with the covariant derivative.
- [3] arXiv:2404.18938 [pdf, ps, other]
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Title: On the embedding of $C_3$ in $E_8$Authors: Robert A. WilsonComments: 14 pagesSubjects: General Physics (physics.gen-ph); High Energy Physics - Phenomenology (hep-ph)
I investigate the structure of $E_8$ under the action of the subalgebra/subgroup $A_1+G_2+C_3$, as a potential route to unification of the fundamental forces of nature into a single algebraic structure. The particular real form $E_{8(-24)}$ supports a decomposition into compact $G_2$ plus split $A_1+C_3$, which allows a restriction from $G_2$ to $SU(3)$ for QCD, together with split $SL_2(\mathbb R)$ to break the symmetry of the weak interaction and give mass to the bosons. The factor $C_3$ contains a copy of the Lorentz group $SL_2(\mathbb C)$ and extends the `spacetime' symmetries to the full group of symplectic symmetries of $3+3$-dimensional phase space.
- [4] arXiv:2404.18941 [pdf, other]
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Title: Magnetic control of magnetotactic bacteria swarmsSubjects: Biological Physics (physics.bio-ph)
Magnetotactic bacteria (MTB) are of significant fundamental and practical interest, especially for applications such as drug delivery and general-purpose object manipulators and payload carriers. While magnetic and other modes of control for individual MTB have been demonstrated, formation, motion and control of MTB swarms are much less studied and understood. Here, we present a torque dipole-based theoretical model for magnetic control of MTB swarms and two methods for swarm formation, and provide experimental validation of the proposed motion model. Model predictions are in good qualitative and quantitative agreement with experiments and literature. Additionally, we were able to determine the torque generated by Magnetospirillium gryphiswaldense (MSR-1) MTB, and the value corresponds to the reported estimates reasonably well.
- [5] arXiv:2404.18945 [pdf, other]
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Title: Advanced analysis of single-molecule spectroscopic dataComments: 22 pages, 19 figuresSubjects: Biological Physics (physics.bio-ph); Chemical Physics (physics.chem-ph); Data Analysis, Statistics and Probability (physics.data-an); Optics (physics.optics)
We present Full SMS, a multipurpose graphical user interface (GUI)-based software package for analysing single-molecule spectroscopy (SMS) data. SMS typically delivers multiparameter data -- such as fluorescence brightness, lifetime, and spectra -- of molecular- or nanometre-scale particles such as single dye molecules, quantum dots, or fluorescently labelled biological macromolecules. Full SMS allows an unbiased statistical analysis of fluorescence brightness through level resolution and clustering, analysis of fluorescence lifetimes through decay fitting, as well as the calculation of second-order correlation functions and the display of fluorescence spectra and raster-scan images. Additional features include extensive data filtering options, a custom HDF5-based file format, and flexible data export options. The software is open source and written in Python but GUI-based so it may be used without any programming knowledge. A multi-process architecture was employed for computational efficiency. The software is also designed to be easily extendable to include additional import data types and analysis capabilities.
- [6] arXiv:2404.18946 [pdf, other]
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Title: Align-Free Multi-Plane Phase RetrievalSubjects: Optics (physics.optics); Information Retrieval (cs.IR); Image and Video Processing (eess.IV)
The multi-plane phase retrieval method provides a budget-friendly and effective way to perform phase imaging, yet it often encounters alignment challenges due to shifts along the optical axis in experiments. Traditional methods, such as employing beamsplitters instead of mechanical stage movements or adjusting focus using tunable light sources, add complexity to the setup required for multi-plane phase retrieval. Attempts to address these issues computationally face difficulties due to the variable impact of diffraction, which renders conventional homography techniques inadequate. In our research, we introduce a novel Adaptive Cascade Calibrated (ACC) strategy for multi-plane phase retrieval that overcomes misalignment issues. This technique detects feature points within the refocused sample space and calculates the transformation matrix for neighboring planes on-the-fly to digitally adjust measurements, facilitating alignment-free multi-plane phase retrieval. This approach not only avoids the need for complex and expensive optical hardware but also simplifies the imaging setup, reducing overall costs. The effectiveness of our method is validated through simulations and real-world optical experiments.
- [7] arXiv:2404.18951 [pdf, ps, other]
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Title: Photon frequency variation in non-linear electro-magnetismSubjects: General Physics (physics.gen-ph)
We set a generalised non-linear Lagrangian, encompassing Born-Infeld and Heisenberg-Euler theories among others. The Lagrangian reduces to the Maxwell Lagrangian at lowest order. The field is composed by a propagating light-wave in an electro-magnetic background. The wave exhibits energy variation when the background is space-time dependent. In the photon description, this implies a red or a blue shift, like what we obtained in massive theories, as the de Broglie-Proca or effective mass theories as the Standard-Model Extension under Lorentz symmetry violation. The two results, photon energy-conservation and the frequency shift are instead new for non-linear electro-magnetism. We conclude by discussing how these static frequency shifts when added to the expansion red shift allow new interpretations in cosmology or for atomic spectra. We finally consider the consequences on the Poincar\'e symmetry.
- [8] arXiv:2404.18954 [pdf, ps, other]
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Title: The Classical Point Particle Singularity: An Illusion in GR and Elsewhere!Comments: 19 pages, 3 figures, 1 tableSubjects: General Physics (physics.gen-ph)
Singularities in Newton's gravity, in general relativity, GR, in Coulomb's law, and elsewhere in classical physics, stem from two ill conceived assumptions that, a) there are point-like entities with finite masses, charges, etc., packed in zero volumes, and b) the non-quantum assumption that these point-like entities can be assigned precise coordinates and momenta. In the case of GR, we argue that the classical energy-momentum tensor in Einstein's field equation is that of a collection of point particles and is prone to singularity. In compliance with Heisenberg's uncertainty principle, we propose replacing each constituent of the gravitating matter with a suitable quantum mechanical equivalent, here a Yukawa-ameliorated Klein-Gordon (YKG) field. YKG fields are spatially distributed entities. They do not end up in singular spacetime points nor predict singular blackholes. On the other hand, YKG waves reach infinity as $\frac{1}{r}e^{-(\kappa\pm i k)r}$. They create non-Newtonian and non-GR gravity forces that die out as $r^{-1}$ as opposed to $r^{-2}$. This feature alone is capable of explaining the observed flat rotation curves of spiral galaxies, and one may interpret them as alternative gravities, dark matter paradigms, etc. There are ample observational data encapsulated in the Tully-Fisher relation to support these conclusions.
- [9] arXiv:2404.18987 [pdf, other]
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Title: Definition of vortex boundary using stagnation pressureComments: 9 pages, 8 figuresSubjects: Fluid Dynamics (physics.flu-dyn)
A novel method is proposed to identify vortex boundary and center of rotation based on tubular surfaces of constant stagnation pressure and minimum of the stagnation pressure gradient. The method is derived from Crocco's theorem, which ensures that the gradient of stagnation pressure is orthogonal to both the velocity and vorticity vectors. The method is Galilean invariant, requires little processing and is robust. It enables visualization of complex turbulent flows and provides a physically consistent definition of vortex boundaries for quantitative analyses. This vortex boundary is a material surface that is representative of the kinematics of the flow by construction, constitutes a vortex tube, ensures conservation of circulation in the inviscid limit and provides a unique relation to the conservation of momentum equations and vortex loads.
- [10] arXiv:2404.19022 [pdf, ps, other]
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Title: Mobility and Threshold Voltage Extraction in Transistors with Gate-Voltage-Dependent Contact ResistanceSubjects: Applied Physics (physics.app-ph); Other Condensed Matter (cond-mat.other)
The mobility of emerging (e.g., two-dimensional, oxide, organic) semiconductors is commonly estimated from transistor current-voltage measurements. However, such devices often experience contact gating, i.e., electric fields from the gate modulate the contact resistance during measurements, which can lead conventional extraction techniques to estimate mobility incorrectly even by a factor >2. This error can be minimized by measuring transistors at high gate-source bias, |$V_\mathrm{gs}$|, but this regime is often inaccessible in emerging devices that suffer from high contact resistance or early gate dielectric breakdown. Here, we propose a method of extracting mobility in transistors with gate-dependent contact resistance that does not require operation at high |$V_\mathrm{gs}$|, enabling accurate mobility extraction even in emerging transistors with strong contact gating. Our approach relies on updating the transfer length method (TLM) and can achieve <10% error even in regimes where conventional techniques overestimate mobility by >2$\times$.
- [11] arXiv:2404.19030 [pdf, other]
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Title: A High-Fidelity Methodology for Particle-Resolved Direct Numerical SimulationsSubjects: Fluid Dynamics (physics.flu-dyn)
We present a novel computational method for direct numerical simulations of particle-laden flows with fully-resolved particles (PR-DNS). The method is based on the recently developed Volume-Filtering Immersed Boundary method [Dave et al, Journal of Computational Physics, 487:112136, 2023] derived by volume-filtering the transport equations. This approach is mathematically and physically rigorous, in contrast to other PR-DNS methods which rely on ad-hoc numerical schemes to impose no-slip boundary conditions on the surface of particles. With the present PR-DNS strategy, we show that the ratio of filter size to particle diameter acts as a parameter that controls the level of fidelity. In the limit where this ratio is very small, a well-resolved PR-DNS is obtained. Conversely, when the ratio of filter size to particle diameter is large, a classic point-particle method is obtained. The discretization of the filtered equations is discussed and compared to other PR-DNS strategies based on direct-forcing immersed boundary methods. Numerical examples with sedimenting resolved particles are discussed.
- [12] arXiv:2404.19035 [pdf, other]
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Title: Improved pressure-gradient sensor for the prediction of separation onset in RANS modelsSubjects: Fluid Dynamics (physics.flu-dyn)
We improve upon two key aspects of the Menter shear stress transport (SST) turbulence model: (1) We propose a more robust adverse pressure gradient sensor based on the strength of the pressure gradient in the direction of the local mean flow; (2) We propose two alternative eddy viscosity models to be used in the adverse pressure gradient regions identified by our sensor. Direct numerical simulations of the Boeing Gaussian bump are used to identify the terms in the baseline SST model that need correction, and a posteriori Reynolds-averaged Navier-Stokes calculations are used to calibrate coefficient values, leading to a model that is both physics driven and data informed. The two sensor-equipped models are applied to two thick airfoils representative of modern wind turbine applications, the FFA-W3-301 and the DU00-W-212, with maximum thicknesses of 30% and 20% of their chord lengths, respectively. While the baseline SST model predicts stall (onset of separation) $3^\circ$ to $5^\circ$ late for all cases considered, the proposed models predict stall within the margins of experimental uncertainty, which greatly improves the prediction of the maximum lift generated. For the FFA airfoil, the models also improve the prediction of the linear region of the lift curve likely due to their improved prediction of a pressure-side separation at low angles of attack. The models are shown to generalize well across the two airfoil geometries (despite their difference in thickness) and across almost a factor of 10 in variations in chord-based Reynolds numbers from $1.6\times10^6$ to $1.5\times10^7$.
- [13] arXiv:2404.19054 [pdf, other]
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Title: Bounds to the Basset-Boussinesq force on particle laden stratified flowsSubjects: Fluid Dynamics (physics.flu-dyn); Atmospheric and Oceanic Physics (physics.ao-ph); Computational Physics (physics.comp-ph)
The Basset-Boussinesq force is often perfunctory neglected when studying small inertial particles in turbulence. The force results from the diffusion of vorticity from the particles, and as it depends on the particles past history, it complicates the dynamics by turning their equations of motion into integro-differential equations. However, this force is of the same order as other viscous forces acting on the particles, and beyond convenience, the reasons for neglecting it are unclear. We derive strict bounds for the magnitude of the Basset-Boussinesq force in stably stratified flows, in contexts of interest for geophysical turbulence. The bounds are validated by direct numerical simulations. The Basset-Boussinesq force can be neglected when a buoyancy Stokes number $\textrm{Sb} = N \tau_p$ is small, where $N$ is the flow Brunt-V\"ais\"al\"a frequency and $\tau_p$ is the particles Stokes time. For sufficiently strong stratification, or particles with large inertia, this force must be considered in the dynamics.
- [14] arXiv:2404.19072 [pdf, other]
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Title: Influence of the downstream blade sweep on cross-flow turbine performanceSubjects: Fluid Dynamics (physics.flu-dyn)
Cross-flow turbine blades encounter a relatively undisturbed inflow for the first half of each rotational cycle ("upstream sweep") and then pass through their own wake for the latter half ("downstream sweep"). While most research on cross-flow turbine optimization focuses on the power-generating upstream sweep, we use singled-bladed turbine experiments to show that the downstream sweep strongly affects time-averaged performance. We find that power generation from the upstream sweep continues to increase beyond the optimal tip-speed ratio. In contrast, the power consumption from the downstream sweep begins to increase approximately linearly beyond the optimal tip-speed ratio due in part to an increasingly unfavorable orientation of lift and drag relative to the rotation direction as well as high tangential blade velocities. Downstream power degradation increases faster than upstream power generation, indicating the downstream sweep strongly influences the optimal tip-speed ratio. In addition, particle image velocimetry data is obtained inside the turbine swept area at three tip-speed ratios. This illuminates the mechanisms underpinning the observed performance degradation in the downstream sweep and motivates an analytical model for a limited case with high induction. Performance results are shown to be consistent across 55 unique combinations of chord-to-radius ratio, preset pitch angle, and Reynolds number, underscoring the general relevance of the downstream sweep.
- [15] arXiv:2404.19084 [pdf, ps, other]
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Title: Depth-Resolved Characterization of Centrifugal Disk Finishing of Additively Manufactured Inconel 718Subjects: Applied Physics (physics.app-ph); Materials Science (cond-mat.mtrl-sci)
Surface characteristics are a major contributor to the in-service performance, particularly fatigue life, of additively manufactured (AM) components. Centrifugal disk finishing (CDF) is one of many rigid media, abrasive machining processes employed to smooth the surfaces and edges of AM components. Within the general family of abrasive machining processes currently applied to AM, CDF is moderate in terms of material removal rate and the inertial forces exerted. How CDF alters the underlying microstructure of the processed surface is currently unknown. Here we employ profilometry and high-energy X-ray diffraction to characterize surface finish, crystallographic texture, and anisotropic distributions of residual microscale strain as a function of depth in CDF-finished Inconel 718 manufactured with laser powder bed fusion. Surfaces are finished using both unimodal and bimodal finishing media size distributions. We find that CDF will remove surface textures from AM components, but generally not alter the bulk texture. CDF is also found to impart significant amounts of residual microscale strain into the first 100 $\mu$m from the sample surface.
- [16] arXiv:2404.19142 [pdf, other]
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Title: Purcell enhanced optical refrigerationComments: 6 pagesSubjects: Optics (physics.optics); Quantum Physics (quant-ph)
Optical refrigeration of solids with anti-Stokes fluorescence has been widely explored as a vibration-free cryogenic cooling technology. A minimum temperature of 87 K has been demonstrated with rare-earth ion doped crystals using optical refrigeration. However, the depletion of the upper-lying energy levels in the ground state manifold hinders further cooling to below liquid nitrogen (LN$_2$) temperatures, confining its applications. In this work, we introduce a Purcell enhanced optical refrigeration method to circumvent this limitation. This approach enhances the emission of high energy photons by coupling to a nearby nanocavity, blue shifting the mean emission wavelength. Such Purcell enhanced emission facilitates cooling starting from a lower energy level in the ground state manifold, which exhibits a higher occupation below LN$_2$ temperatures. Using our experimentally measured optical coefficients, our theoretical analysis predicts a minimum achievable temperature of 38 K for a Yb$^{3+}$:YLiF$_{4}$ nanocrystal near a cavity under realistic conditions. The proposed method is applicable to other rare-earth ion doped materials and semiconductors, and will have applications in creating superconducting and other quantum devices with solid-state cooling.
- [17] arXiv:2404.19158 [pdf, other]
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Title: Polymer Collapse and Liquid-Liquid Phase-Separation are Coupled in a Generalized Prewetting TransitionComments: 12 pages, 5 figuresSubjects: Biological Physics (physics.bio-ph); Statistical Mechanics (cond-mat.stat-mech); Subcellular Processes (q-bio.SC)
The three-dimensional organization of chromatin is thought to play an important role in controlling gene expression. Specificity in expression is achieved through the interaction of transcription factors and other nuclear proteins with particular sequences of DNA. At unphysiological concentrations many of these nuclear proteins can phase-separate in the absence of DNA, and it has been hypothesized that, in vivo, the thermodynamic forces driving these phases help determine chromosomal organization. However it is unclear how DNA, itself a long polymer subject to configurational transitions, interacts with three-dimensional protein phases. Here we show that a long compressible polymer can be coupled to interacting protein mixtures, leading to a generalized prewetting transition where polymer collapse is coincident with a locally stabilized liquid droplet. We use lattice Monte-Carlo simulations and a mean-field theory to show that these phases can be stable even in regimes where both polymer collapse and coexisting liquid phases are unstable in isolation, and that these new transitions can be either abrupt or continuous. For polymers with internal linear structure we further show that changes in the concentration of bulk components can lead to changes in three-dimensional polymer structure. In the nucleus there are many distinct proteins that interact with many different regions of chromatin, potentially giving rise to many different Prewet phases. The simple systems we consider here highlight chromatin's role as a lower-dimensional surface whose interactions with proteins are required for these novel phases.
- [18] arXiv:2404.19163 [pdf, other]
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Title: Efficient Mixed-Precision Matrix Factorization of the Inverse Overlap Matrix in Electronic Structure Calculations with AI-Hardware and GPUsComments: 12 pages, 4 figures, 1 table and a few algorithmsSubjects: Computational Physics (physics.comp-ph); Materials Science (cond-mat.mtrl-sci); Mathematical Physics (math-ph)
In recent years, a new kind of accelerated hardware has gained popularity in the Artificial Intelligence (AI) and Machine Learning (ML) communities which enables extremely high-performance tensor contractions in reduced precision for deep neural network calculations. In this article, we exploit Nvidia Tensor cores, a prototypical example of such AI/ML hardware, to develop a mixed precision approach for computing a dense matrix factorization of the inverse overlap matrix in electronic structure theory, $S^{-1}$. This factorization of $S^{-1}$, written as $ZZ^T=S^{-1}$, is used to transform the general matrix eigenvalue problem into a standard matrix eigenvalue problem. Here we present a mixed precision iterative refinement algorithm where $Z$ is given recursively using matrix-matrix multiplications and can be computed with high performance on Tensor cores. To understand the performance and accuracy of Tensor cores, comparisons are made to GPU-only implementations in single and double precision. Additionally, we propose a non-parametric stopping criteria which is robust in the face of lower precision floating point operations. The algorithm is particularly useful when we have a good initial guess to $Z$, for example, from previous time steps in quantum-mechanical molecular dynamics simulations or from a previous iteration in a geometry optimization.
- [19] arXiv:2404.19169 [pdf, ps, other]
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Title: Correlations between X-rays, Visible Light and Drive-Beam Energy Loss Observed in Plasma Wakefield Acceleration Experiments at FACET-IIAuthors: Chaojie Zhang, Doug Storey, Pablo San Miguel Claveria, Zan Nie, Ken A. Marsh, Warren B. Mori, Erik Adli, Weiming An, Robert Ariniello, Gevy J. Cao, Christine Clark, Sebastien Corde, Thamine Dalichaouch, Christopher E. Doss, Claudio Emma, Henrik Ekerfelt, Elias Gerstmayr, Spencer Gessner, Claire Hansel, Alexander Knetsch, Valentina Lee, Fei Li, Mike Litos, Brendan O'Shea, Glen White, Gerry Yocky, Viktoriia Zakharova, Mark Hogan, Chan JoshiComments: 20 pages, 6 figuresSubjects: Plasma Physics (physics.plasm-ph); Accelerator Physics (physics.acc-ph)
This study documents several correlations observed during the first run of the plasma wakefield acceleration experiment E300 conducted at FACET-II, using a single drive electron bunch. The established correlations include those between the measured maximum energy loss of the drive electron beam and the integrated betatron x-ray signal, the calculated total beam energy deposited in the plasma and the integrated x-ray signal, among three visible light emission measuring cameras, and between the visible plasma light and x-ray signal. The integrated x-ray signal correlates almost linearly with both the maximum energy loss of the drive beam and the energy deposited into the plasma, demonstrating its usability as a measure of energy transfer from the drive beam to the plasma. Visible plasma light is found to be a useful indicator of the presence of wake at three locations that overall are two meters apart. Despite the complex dynamics and vastly different timescales, the x-ray radiation from the drive bunch and visible light emission from the plasma may prove to be effective non-invasive diagnostics for monitoring the energy transfer from the beam to the plasma in future high-repetition-rate experiments.
- [20] arXiv:2404.19172 [pdf, other]
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Title: Striking the Right Balance of Encoding Electron Correlation in the Hamiltonian and the Wavefunction AnsatzComments: 12 pages, 4 figures, 1 tableSubjects: Chemical Physics (physics.chem-ph); Strongly Correlated Electrons (cond-mat.str-el); Computational Physics (physics.comp-ph); Quantum Physics (quant-ph)
Multi-configurational electronic structure theory delivers the most versatile approximations to many-electron wavefunctions, flexible enough to deal with all sorts of transformations, ranging from electronic excitations, to open-shell molecules and chemical reactions. Multi-configurational models are therefore essential to establish universally applicable, predictive ab initio methods for chemistry. Here, we present a discussion of explicit correlation approaches which address the nagging problem of dealing with static and dynamic electron correlation in multi-configurational active-space approaches. We review the latest developments and then point to their key obstacles. Our discussion is supported by new data obtained with tensor network methods. We argue in favor of simple electrons-only correlator expressions that may allow one to define transcorrelated models in which the correlator does not bear a dependence on molecular structure.
- [21] arXiv:2404.19184 [pdf, ps, other]
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Title: Tunable plasmonic properties of spatially overlapping asymmetric nanoparticle dimersSubjects: Optics (physics.optics)
In this work, the plasmonic properties of nanoparticle dimers with optical responses over a wide spectral range have been investigated by varying the inter-particle gap, dimer geometry, gap morphology, nanoparticle composition, and refractive index of the surrounding medium. In particular, we have theoretically investigated the plasmonic properties of spatially overlapping symmetric gold nanodisks, shape-asymmetric gold nanodisk nanoplates, and compositionally asymmetric gold-silver nanodisk dimers by varying the gap separation from touching to overlapping regime. In such a configuration, we have observed the appearance of a dominant bonding dimer plasmon (BDP) mode that blue-shifts as gap separation turns from touching to overlapping. In addition, it is found that asymmetric dimer produces a broader resonance shift compared to symmetric dimer because of the hybridization of bright and dark plasmon modes, making it a viable option for sensing applications. It is also found that blue shifting of the plasmon mode occurred by changing the gap morphology of the contacting region of the dimer for fixed nanoparticle size and dimer overlapping. Moreover, we explored the influence of overlapping nanoparticle dimer thickness and observed a notable resonance shift by varying the thickness of the nanoparticle dimer. Finally, based on this tunable resonance shift, we explored the sensing applications of bonding dimer plasmon mode with optimized geometries. Thus, the computed figure of merit (FOM) of the overlapping symmetric, shape-asymmetric, and compositionally asymmetric nanoparticle dimers were found to be 1.55, 2.08, and 3.04, respectively, and comparative advantages among the three configurations with implications for surface-based sensing have been thoroughly discussed.
- [22] arXiv:2404.19203 [pdf, ps, other]
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Title: Thermal Performance of a Liquid-cooling Assisted Thin Wickless Vapor ChamberAuthors: Arani Mukhopadhyay, Anish Pal, Mohamad Jafari Gukeh, Constantine M. Megaridis (Mechanical and Industrial Engineering, University of Illinois Chicago, IL, US.)Comments: Presented at IEEE ITherm (Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems) 2023. Orlando, FL, US. Corresponding: cmm@uic.eduSubjects: Applied Physics (physics.app-ph); Hardware Architecture (cs.AR); Systems and Control (eess.SY)
The ever-increasing need for power consumption in electronic devices, coupled with the requirement for thinner size, calls for the development of efficient heat spreading components. Vapor chambers (VCs), because of their ability to effectively spread heat over a large area by two-phase heat transfer, seem ideal for such applications. However, creating thin and efficient vapor chambers that work over a wide range of power inputs is a persisting challenge. VCs that use wicks for circulating the phase changing media, suffer from capillary restrictions, dry-out, clogging, increase in size and weight, and can often be costly. Recent developments in wick-free wettability patterned vapor chambers replace traditional wicks with laser-fabricated wickless components. An experimental setup allows for fast testing and experimental evaluation of water-charged VCs with liquid-assisted cooling. The sealed chamber can maintain vacuum for long durations, and can be used for testing of very thin wick-free VCs. This work extends our previous study by decreasing overall thickness of the wick-free VC down to 3 mm and evaluates its performance. Furthermore, the impact of wettability patterns on VC performance is investigated, by carrying out experiments both in non-patterned and patterned VCs. Experiments are first carried out on a wick-free VC with no wettability patterns and comprising of an entirely superhydrophilic evaporator coupled with a hydrophobic condenser. Thereafter, wettability patterns that aid the rapid return of water to the heated site on the evaporator and improve condensation on the condenser of the vapor chamber are implemented. The thermal characteristics show that the patterned VCs outperform the non-patterned VCs under all scenarios. The patterned VCs exhibit low thermal resistance independent of fluid charging ratio withstanding higher power inputs without thermal dry-outs.
- [23] arXiv:2404.19280 [pdf, ps, other]
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Title: Unveiling the effects of Cu doping on the H2 activation by CeO2 surface frustrated Lewis pairsSubjects: Chemical Physics (physics.chem-ph)
Recently, the solid-state frustrated Lewis pairs (FLPs) on the surface of CeO2 have been demonstrated to effectively catalyze the selective hydrogenation of unsaturated substrates, hence, the relationship between their intrinsic properties and H2 activation at the atomic scale has attracted great attention. In this work, the effects of Cu doping on the intrinsic FLPs properties for different facets of CeO2 is investigated by using density functional theory calculations, including the geometric parameters between Lewis acid-base centers, and the reactivity of Lewis acid-base towards H2 activation. The study demonstrates that introducing O vacancies on different crystal facets of CeO2 creates FLPs with the ability to efficiently cleavage hydrogen molecules. After the substitution of Ce with Cu, the inadequate electron availability of Cu to bond with O contributes to a reduction in the formation energy of O vacancies. Importantly, Cu exert an influence not only on the intrinsic properties of FLPs but also on the formation of new Ce-O and Cu-O FLPs. Considering the H2 activation, the doping of Cu results in an enhancement for the thermodynamics by decreasing the reaction energies, while a hinderance for the kinetics by increasing the energy barriers. Overall, with these theoretical investigations, we propose certain hints for the future experimental studies concerning the synthesis of Cu doped CeO2 catalysts for the H2 activation and hydrogenation reactions.
- [24] arXiv:2404.19285 [pdf, other]
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Title: Three-dimensional plasmoid-mediated reconnection and turbulence in Hall magnetohydrodynamicsSubjects: Plasma Physics (physics.plasm-ph); Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)
Plasmoid instability accelerates reconnection in collisional plasmas by transforming a laminar reconnection layer into numerous plasmoids connected by secondary current sheets in two dimensions (2D) and by fostering self-generated turbulent reconnection in three dimensions (3D). In large-scale astrophysical and space systems, plasmoid instability likely initiates in the collisional regime but may transition into the collisionless regime as the fragmentation of the current sheet progresses toward kinetic scales. Hall MHD models are widely regarded as a simplified yet effective representation of the transition from collisional to collisionless reconnection. However, plasmoid instability in 2D Hall MHD simulations often leads to a single-X-line reconnection configuration, which significantly differs from fully kinetic particle-in-cell simulation results. This study shows that single-X-line reconnection is less likely to occur in 3D compared to 2D. Moreover, depending on the Lundquist number and the ratio between the system size and the kinetic scale, Hall MHD can also realize 3D self-generated turbulent reconnection. We analyze the features of the self-generated turbulent state, including the energy power spectra and the scale dependence of turbulent eddy anisotropy.
- [25] arXiv:2404.19327 [pdf, ps, other]
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Title: Assessment of physical schemes for WRF model in convection-permitting mode over southern Iberian PeninsulaAuthors: Feliciano Solano-Farías, Matilde García-Valdecasas Ojeda, David Donaire-Montaño, Juan José Rosa-Cánovas, Yolanda Castro-Diez, Maria Jesús Esteban-Parra, Sonia Raquel Gámiz-FortisJournal-ref: Atmospheric Research, Volume 299, 1 April 2024, 107175Subjects: Atmospheric and Oceanic Physics (physics.ao-ph); Applied Physics (physics.app-ph)
Convection-permitting models (CPMs) enable the representation of meteorological variables at horizontal high resolution spatial scales (higher than 4 km), where convection plays a significant role. Physical schemes need to be evaluated considering factors in the studied region such as orography and climate variability. This study investigates the sensitivity of the WRF model as CPM to the use of different physics schemes on Andalusia, a complex orography region in southern Iberian Peninsula (IP). A set of 1-year WRF simulations was completed based on two one-way nested domains: the parent domain (d01) spanning the entire IP with 5 km spatial resolution and the nested domain (d02) for the region of Andalusia at 1 km of spatial resolution. 12 physic schemes were examined from combinations of microphysics (MP) schemes including THOMPSON, WRF single moment 6-class (WSM6), and WRF single moment 7-class (WSM7), and different options for the convection in d01, the Grell 3D (G3), Grell-Freitas (GF), Kain-Fritsch (KF), and deactivated cumulus parameterization (OFF). The simulated precipitation and 2-m temperature for the year 2018, a very wet year, were compared with observational datasets to determine the optimal WRF configuration, including point-to-point and station-point comparisons at different time aggregations. In general, greater differences were shown when comparing the results of convection schemes in d01. Simulations completed with GF or OFF presented better performance compared to the reference datasets. Concerning the MP, although THOMPSON showed a better fit in high mountain areas, it generally presents a worse agreement with the reference datasets. In terms of temperature, the results were very similar and, therefore, the selection of the best configuration was based mainly on the precipitation results with the WSM7-GF scheme being suitable for Andalusia region.
- [26] arXiv:2404.19333 [pdf, ps, other]
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Title: Super-resolution by converting evanescent waves in microsphere to propagating and transfer function from its surface to nano-jetAuthors: Y. Ben-AryehComments: 13 pagesSubjects: Optics (physics.optics)
The EM waves transmitted through a thin object with fine structures is observed, by microsphere located above the object. While the waves include both evanescent and propagating waves, the high resolution is obtained by the evanescent ones, including the information on the fine structures of the object. Description of this process is divided into two parts: a) The super resolution is analyzed by using Helmholtz equation for the evanescent waves transmitted from the object to the microsphere surface. b) Using boundary condition, the electric fields on the inner surface of the microsphere includes both the evanescent and propagating waves. The transmission of these waves to a nano jet is produced by a transfer function, including convolution between the spatial modes of the evanescent waves with those of the microsphere, which increases the conversion of the evanescent waves to propagating waves, and thus increase the resolution.
- [27] arXiv:2404.19347 [pdf, other]
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Title: The influence of non-Newtonian behaviors of blood on the hemodynamics past a bileaflet mechanical heart valveSubjects: Fluid Dynamics (physics.flu-dyn)
This study employs extensive three-dimensional direct numerical simulations (DNS) to investigate the influence of blood non-Newtonian behaviors on the hemodynamics around a bileaflet mechanical heart valve under both steady inflow and physiologically realistic pulsatile flow conditions. Under steady inflow conditions, the study reveals that blood rheology impacts velocity and pressure field variations, as well as the values of clinically important surface and time-averaged parameters like wall shear stress (WSS) and pressure recovery. Notably, this influence is most pronounced at low Reynolds numbers, gradually diminishing as the Reynolds number increases. For instance, surface-averaged WSS values obtained with the non-Newtonian shear-thinning power-law model exceed those obtained with the Newtonian model. At $Re = 750$, this difference reaches around 67\%, reducing to less than 1\% at $Re = 5000$. Correspondingly, pressure recovery downstream of the valve leaflets is lower for the shear-thinning blood than the constant viscosity one, with the difference decreasing as the Reynolds number increases. On the other hand, in pulsatile flow conditions, jets formed between the leaflets and the valve housing wall are shorter than steady inflow conditions. Additionally, surface-averaged wall shear stress and blood damage (BD) parameter values are higher (with differences more than 13\% and 47\%, respectively) during the peak stage of the cardiac cycle, especially for blood exhibiting non-Newtonian yield stress characteristics compared to the shear-thinning or constant viscosity characteristics. Therefore, blood non-Newtonian behaviors, including shear-thinning and yield stress behaviors, exert a considerable influence on the hemodynamics around a mechanical heart valve.
- [28] arXiv:2404.19351 [pdf, other]
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Title: Deep Learning Forecasts Caldera Collapse Events at Kīlauea VolcanoSubjects: Geophysics (physics.geo-ph); Machine Learning (cs.LG)
During the three month long eruption of K\=ilauea volcano, Hawaii in 2018, the pre-existing summit caldera collapsed in over 60 quasi-periodic failure events. The last 40 of these events, which generated Mw >5 very long period (VLP) earthquakes, had inter-event times between 0.8 - 2.2 days. These failure events offer a unique dataset for testing methods for predicting earthquake recurrence based on locally recorded GPS, tilt, and seismicity data. In this work, we train a deep learning graph neural network (GNN) to predict the time-to-failure of the caldera collapse events using only a fraction of the data recorded at the start of each cycle. We find that the GNN generalizes to unseen data and can predict the time-to-failure to within a few hours using only 0.5 days of data, substantially improving upon a null model based only on inter-event statistics. Predictions improve with increasing input data length, and are most accurate when using high-SNR tilt-meter data. Applying the trained GNN to synthetic data with different magma pressure decay times predicts failure at a nearly constant stress threshold, revealing that the GNN is sensing the underling physics of caldera collapse. These findings demonstrate the predictability of caldera collapse sequences under well monitored conditions, and highlight the potential of machine learning methods for forecasting real world catastrophic events with limited training data.
- [29] arXiv:2404.19352 [pdf, other]
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Title: Aluminum nuclear demagnetization refrigerator for powerful continuous coolingAuthors: Matthias Raba, Sébastien Triqueneaux, James Butterworth, David Schmoranzer, Emilio Barria, Jérôme Debray, Guillaume Donnier-Valentin, Thibaut Gandit, Anne Gerardin, Johannes Goupy, Olivier Tissot, Eddy Collin, Andrew FeffermanSubjects: Instrumentation and Detectors (physics.ins-det)
Many laboratories routinely cool samples to 10 mK, but relatively few can cool condensed matter below 1 mK. Easy access to the microkelvin range would propel fields such as quantum sensors and quantum materials. Such temperatures are achieved with adiabatic nuclear demagnetization. Existing nuclear demagnetization refrigerators (NDR) are "single-shot", and the recycling time is incompatible with proposed sub-mK experiments. Furthermore, a high cooling power is required to overcome the excess heat load of order nW on NDR pre-cooled by cryogen-free dilution refrigerators. We report the performance of an aluminum NDR designed for powerful cooling when part of a dual stage continuous NDR (CNDR). Its thermal resistance is minimized to maximize the cycling rate of the CNDR and consequently its cooling power. At the same time, its susceptibility to eddy current heating is minimized. A CNDR based on two of the aluminum NDR presented here would have a cooling power of approximately 40 nW at 560 $\mu$K.
- [30] arXiv:2404.19374 [pdf, other]
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Title: Perspectives of a single-anode cylindrical chamber operating in ionization mode and high gas pressureAuthors: R. Bouet, J. Busto, V. Cecchini, P. Charpentier, M. Chapellier, A. Dastgheibi-Fard, F. Druillole, C. Jollet, P. Hellmuth, M. Gros, P. Lautridou, A. Meregaglia, X. F. Navick, F. Piquemal, M. Roche, B. ThomasSubjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex)
As part of the R2D2 (Rare Decays with Radial Detector) R&D, the use of a gas detector with a spherical or cylindrical cathode, equipped with a single anode and operating at high pressure, was studied for the search of rare phenomena such as neutrinoless double-beta decay. The presented measurements were obtained with a cylindrical detector, covering gas pressures ranging from 1 to 10 bar in argon and 1 to 6 bar in xenon, using both a point-like source of $^{210}$Po (5.3 MeV $\alpha$ ) and a diffuse source of $^{222}$Rn (5.5 MeV $\alpha$). Analysis and interpretation of the data were developed using the anodic current waveform. Similar detection performances were achieved with both gases, and comparable energy resolutions were measured with both sources. As long as the purity of the gas was sufficient, no significant degradation of the measured energy was observed by increasing the pressure. At the highest operating pressure, an energy resolution better than 1.5% full-width at half-maximum (FWHM) was obtained for both gaseous media, although optimal noise conditions were not reached.
- [31] arXiv:2404.19405 [pdf, other]
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Title: Exploring the role of mean-field potentials and short-range wave function behavior in the adiabatic connectionSubjects: Chemical Physics (physics.chem-ph)
In this article, we explore the construction of Hamiltonians with long-range interactions and their corrections using the short-range behavior of the wave function. A key aspect of our investigation is the examination of the one-particle potential, kept constant in our previous work, and the effects of its optimization on the adiabatic connection.
Our methodology involves the use of a parameter-dependent potential dependent on a single parameter to facilitate practical computations. We analyze the energy errors and densities in a two-electron system (harmonium) under various conditions, employing different confinement potentials and interaction parameters. The study reveals that while the mean-field potential improves the expectation value of the physical Hamiltonian, it does not necessarily improve the energy of the system within the bounds of chemical accuracy.
We also delve into the impact of density variations in adiabatic connections, challenging the common assumption that a mean field improves results. Our findings indicate that as long as energy errors remain within chemical accuracy, the mean field does not significantly outperform a bare potential. This observation is attributed to the effectiveness of corrections based on the short-range behavior of the wave function, a universal characteristic that diminishes the distinction between using a mean field or not. - [32] arXiv:2404.19436 [pdf, other]
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Title: Electro-phononic and magneto-phononic frequency conversionSubjects: Optics (physics.optics); Materials Science (cond-mat.mtrl-sci)
Nonlinear frequency conversion by optical rectification, as well as difference- and sum-frequency generation are fundamental processes for producing electromagnetic radiation at different frequencies. Here, we demonstrate that coherently excited infrared-active phonons can be used as transducers for generating nonlinear electric polarizations and magnetizations via phonon-phonon and phonon-magnon interactions, in a way similar to nonlinear optical frequency conversion. We derive analytical solutions for the time-dependent polarizations and magnetizations for the second-order response to the electric field component of an ultrashort laser pulse. These allow us to define second-order nonlinear electric and magneto-electric susceptibilities that capture the rectification, as well as the impulsive and sum-frequency excitation of coherent phonons and magnons. Our theoretical framework naturally incorporates existing mechanisms and further leads to the prediction of a hybrid magneto-opto-phononic inverse Faraday effect involving photon-phonon-magnon scattering. Our work demonstrates nonlinear phononics as a pathway to controlling the electric polarization and magnetization in solids.
- [33] arXiv:2404.19464 [pdf, other]
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Title: Effect of detachment on Magnum-PSI ELM-like pulses: I. Direct observations and qualitative resultsAuthors: Fabio Federici, Bruce Lipschultz, Gijs R. A. Akkermans, Kevin Verhaegh, Matthew L. Reinke, Ivo G. J. Classen, Magnum-PSI TeamComments: 16 pages, 17 figures, Submitted to Nuclear FusionSubjects: Plasma Physics (physics.plasm-ph)
Conditions similar to those at the end of the divertor leg in a tokamak were replicated in the linear plasma machine Magnum-PSI. The neutral pressure in the target chamber is then increased to cause the target to transition from an attached to a detached state. Superimposed to this steady state regime, ELM-like pulses are reproduced, resulting in a sudden increase in plasma temperature and density, such that the heat flux increases transiently by half an order of magnitude. Visible light emission, target thermography, and Thomson scattering are used to demonstrate that the higher the neutral pressure the more energy is removed from the ELM-like pulse in the volume. If the neutral pressure is sufficiently high, the ELM-like pulse can be prevented from affecting the target and the plasma energy is fully dissipated in the volume instead (ID 4 in Table 1). The visible light images allow the division of the ELM-plasma interaction process of ELM energy dissipation into 3 "stages" ranging from no dissipation to full dissipation (the target plasma is detached). In the second publication related to this study, spectroscopic data is analysed with a Bayesian approach, to acquire insights into the significance of molecular processes in dissipating the plasma energy and particles.
- [34] arXiv:2404.19506 [pdf, ps, other]
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Title: High power single crystal KTA optical parametric amplifier for efficient 1.4-3.5 $μ$m mid-IR radiation generationAuthors: Bianka Csanaková (1 and 2), Ondřej Novák (1), Lukáš Roškot (1 and 2), Jiří Mužík (1), Martin Smrž (1), Helena Jelínková (2), Tomáš Mocek (1) ((1) HiLASE Centre, FZU - Institute of Physics of the Czech Academy of Sciences, Dolní Břežany, Czech Republic, (2) Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic)Comments: 8 pages, 14 figuresSubjects: Optics (physics.optics)
In this paper, we present a single crystal, KTA (potassium titanyl-arsenate, KTiOAsO$_4$) based picosecond optical parametric amplifier pumped by an in-house built 1030 nm Yb:YAG thin-disk laser, capable of tunability from 1.46 to 3.5 $\mu$m, operating at 90 kHz, with high average power in the signal and idler beams. The highest output power of 8.9 W was reached for the 1750 nm signal beam with 19% conversion efficiency and the respective 2500 nm idler beam power was 6.2 W with 13% efficiency. The highest combined signal and idler mid-IR power was obtained at 17 W at the 2060 nm wavelength degeneracy point.
- [35] arXiv:2404.19535 [pdf, other]
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Title: Ferroelectrically-enhanced Schottky barrier transistors for Logic-in-Memory applicationsSubjects: Applied Physics (physics.app-ph); Emerging Technologies (cs.ET)
Artificial neural networks (ANNs) have had an enormous impact on a multitude of sectors, from research to industry, generating an unprecedented demand for tailor-suited hardware platforms. Their training and execution is highly memory-intensive, clearly evidencing the limitations affecting the currently available hardware based on the von Neumann architecture, which requires frequent data shuttling due to the physical separation of logic and memory units. This does not only limit the achievable performances but also greatly increases the energy consumption, hindering the integration of ANNs into low-power platforms. New Logic in Memory (LiM) architectures, able to unify memory and logic functionalities into a single component, are highly promising for overcoming these limitations, by drastically reducing the need of data transfers. Recently, it has been shown that a very flexible platform for logic applications can be realized recurring to a multi-gated Schottky-Barrier Field Effect Transistor (SBFET). If equipped with memory capabilities, this architecture could represent an ideal building block for versatile LiM hardware. To reach this goal, here we investigate the integration of a ferroelectric Hf$_{0.5}$Zr$_{0.5}$O$_2$ (HZO) layer onto Dual Top Gated SBFETs. We demonstrate that HZO polarization charges can be successfully employed to tune the height of the two Schottky barriers, influencing the injection behavior, thus defining the transistor mode, switching it between n and p-type transport. The modulation strength is strongly dependent on the polarization pulse height, allowing for the selection of multiple current levels. All these achievable states can be well retained over time, thanks to the HZO stability. The presented result show how ferroelectric-enhanced SBFETs are promising for the realization of novel LiM hardware, enabling low-power circuits for ANNs execution.
- [36] arXiv:2404.19561 [pdf, other]
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Title: Short term vs. long term: optimization of microswimmer navigation on different time horizonsComments: 18 pages, 5 figuresSubjects: Fluid Dynamics (physics.flu-dyn)
We use reinforcement learning to find strategies that allow microswimmers in turbulence to avoid regions of large strain. This question is motivated by the hypothesis that swimming microorganisms tend to avoid such regions to minimise the risk of predation. We ask which local cues a microswimmer must measure to efficiently avoid such straining regions. We find that it can succeed without directional information, merely by measuring the magnitude of the local strain. However, the swimmer avoids straining regions more efficiently if it can measure the sign of local strain gradients. We compare our results with those of an earlier study [Mousavi et al. arxiv:2309.09641] where a short-time expansion was used to find optimal strategies. We find that the short-time strategies work well in some cases but not in others. We derive a new theory that explains when the time-horizon matters for our optimisation problem, and when it does not. We find the strategy with best performance when the time-horizon coincides with the correlation time of the turbulent fluctuations. We also explain how the update frequency (the frequency at which the swimmer updates its state) affects the found strategies. We find that higher update frequencies yield better performance, as long as the time between updates is smaller than the correlation time of the flow.
- [37] arXiv:2404.19566 [pdf, ps, other]
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Title: Relativity with or without light and MaxwellAuthors: D V RedžićComments: 11 pagesSubjects: Classical Physics (physics.class-ph); History and Philosophy of Physics (physics.hist-ph)
The complex relationship between Einstein's second postulate and the Maxwell electromagnetic theory is elucidated. A simple deduction of the main results of the Ignatowski approach to the theory of relativity is given. The peculiar status of the principle of relativity among the Maxwellians is illustrated.
- [38] arXiv:2404.19570 [pdf, other]
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Title: Morphodynamics of chloroplast network control light-avoidance response in the non-motile dinoflagellate Pyrocystis lunulaSubjects: Biological Physics (physics.bio-ph)
Photosynthetic algae play a significant role in oceanic carbon capture. Their performance, however, is constantly challenged by fluctuations in environmental light conditions. Here, we show that the non-motile single-celled marine dinoflagellate Pyrocystis lunula can internally contract its chloroplast network in response to light. By exposing the cell to various physiological light conditions and applying temporal illumination sequences, we find that network morphodynamics follows simple rules, as established in a mathematical model. Our analysis of the chloroplast structure reveals that its unusual reticulated morphology constitutes properties similar to auxetic metamaterials, facilitating drastic deformations for light-avoidance, while confined by the cell wall. Our study shows how the topologically complex network of chloroplasts is crucial in supporting the dinoflagellate's adaptation to varying light conditions, thereby facilitating essential life-sustaining processes.
- [39] arXiv:2404.19580 [pdf, other]
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Title: Enduring two-dimensional perturbations with significant non-modal growthAuthors: Sharath JoseSubjects: Fluid Dynamics (physics.flu-dyn)
Laminar shear flows can display large non-modal perturbation growth, often through the lift-up mechansm, and can undergo subcritical transition to turbulence. The process is three-dimensional. Two-dimensional (2D) spanwise-independent perturbations are often considered less important as they typically undergo modest levels of transient growth and are short-lived. Strikingly, we show the existence of 2D non-modal perturbations that get amplified significantly and survive for long periods of time. Two-layer and three-layer viscosity stratified plane shear flows are taken to be the mean states. We show that while the two-layer flow is always modally stable, the three-layer flow supports exponential growing instabilities only when the middle layer is the least viscous. The non-modal stability analysis is performed only for the modally stable configurations of these flows. At later times, the non-modal perturbations feature strongly confined vortical structures near the interface in the two-layer flow. For the three-layer flow, similar observations are noted when all the three layers have different shear rates with the vortices prominently seen in the vicinity of the interface between the least viscous and middle layers. For the three-layer flow configuration with the outer layers having equal shear rates, the perturbation structure shows symmetry about the middle layer and evolves such that the Orr mechanism can repeatedly occur in a regenerative manner resulting in the perturbation energy evolving in a markedly non-monotonic fashion. When these same perturbations are introduced in a uniform plane shear flow, the extent of non-modal transient growth is shown to be significantly smaller.
- [40] arXiv:2404.19584 [pdf, other]
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Title: Broadband microwave-rate dark pulse microcombs in dissipation-engineered LiNbO$_3$ microresonatorsAuthors: Xiaomin Lv, Binbin Nie, Chen Yang, Rui Ma, Ze Wang, Yanwu Liu, Xing Jin, Kaixuan Zhu, Zhenyu Chen, Du Qian, Guanyu Zhang, Guowei Lv, Qihuang Gong, Fang Bo, Qi-Fan YangSubjects: Optics (physics.optics)
Kerr microcombs generated in optical microresonators provide broadband light sources bridging optical and microwave signals. Their translation to thin-film lithium niobate unlocks second-order nonlinear optical interfaces such as electro-optic modulation and frequency doubling for completing comb functionalities. However, the strong Raman response of LiNbO$_3$ has complicated the formation of Kerr microcombs. Until now, dark pulse microcombs, requiring a double balance between Kerr nonlinearity and normal group velocity dispersion as well as gain and loss, have remained elusive in LiNbO$_3$ microresonators. Here, by incorporating dissipation engineering, we demonstrate dark pulse microcombs with 25 GHz repetition frequency and 200 nm span in a high-$Q$ LiNbO$_3$ microresonator. Resonances near the Raman-active wavelengths are strongly damped by controlling phase-matching conditions of a specially designed pulley coupler. The coherence and tunability of the dark pulse microcombs are also investigated. Our work provides a solution to realize high-power microcombs operating at microwave rates on LiNbO$_3$ chips, promising new opportunities for the monolithic integration of applications spanning communication to microwave photonics.
- [41] arXiv:2404.19599 [pdf, other]
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Title: Parity and time-reversal symmetry violation in diatomic molecules: LaO, LaS and LuOAuthors: Yuly Chamorro, Victor Flambaum, Ronald F. Garcia Ruiz, Anastasia Borschevsky, Lukáš F. PaštekaSubjects: Atomic Physics (physics.atom-ph); Chemical Physics (physics.chem-ph)
The violation of parity (P) and time-reversal (T) symmetry is enhanced in the LaS, LaO and LuO molecules due to the existence of states of opposite parity with small energy differences and the presence of heavy nuclei. We calculate the molecular enhancement for the P, T-violating electron electric dipole moment ($W_{\mathrm{d}}$), scalar-pseudoscalar nucleon-electron interaction ($W_{\mathrm{s}}$), nuclear magnetic quadrupole moment ($W_{\mathrm{M}}$), and for the nuclear spin-dependent P-violating anapole moment ($W_{\mathrm{A}}$). We use the relativistic 4-components coupled cluster method and perform a systematic study to estimate the associated uncertainties in our approach. We find that the individual contribution of each computational parameter to the total uncertainty in a system is approximately the same for all the calculated enhancement factors, summing up to a total uncertainty of $\sim7$\%. We discuss the energy shifts and matrix elements associated with the calculated molecular enhancement factors and relate them to higher-energy P- and P, T- violating interactions.
- [42] arXiv:2404.19600 [pdf, other]
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Title: Stabilized POD Reduced Order Models for convection-dominated incompressible flowsSubjects: Fluid Dynamics (physics.flu-dyn); Numerical Analysis (math.NA)
We present a comparative computational study of two stabilized Reduced Order Models (ROMs) for the simulation of convection-dominated incompressible flow (Reynolds number of the order of a few thousands). Representative solutions in the parameter space, which includes either time only or time and Reynolds number, are computed with a Finite Volume method and used to generate a reduced basis via Proper Orthogonal Decomposition (POD). Galerkin projection of the Navier-Stokes equations onto the reduced space is used to compute the ROM solution. To ensure computational efficiency, the number of POD modes is truncated and ROM solution accuracy is recovered through two stabilization methods: i) adding a global constant artificial viscosity to the reduced dimensional model, and ii) adding a different value of artificial viscosity for the different POD modes. We test the stabilized ROMs for fluid flow in an idealized medical device consisting of a conical convergent, a narrow throat, and a sudden expansion. Both stabilization methods significantly improve the ROM solution accuracy over a standard (non-stabilized) POD-Galerkin model.
- [43] arXiv:2404.19602 [pdf, other]
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Title: Uncertainty quantification for charge transport in GNRs through particle Galerkin methods for the semiclassical Boltzmann equationComments: 26 pages, 6 Figures, 4 TablesSubjects: Computational Physics (physics.comp-ph); Numerical Analysis (math.NA); Applied Physics (physics.app-ph)
In this article, we investigate some issues related to the quantification of uncertainties associated with the electrical properties of graphene nanoribbons. The approach is suited to understand the effects of missing information linked to the difficulty of fixing some material parameters, such as the band gap, and the strength of the applied electric field. In particular, we focus on the extension of particle Galerkin methods for kinetic equations in the case of the semiclassical Boltzmann equation for charge transport in graphene nanoribbons with uncertainties. To this end, we develop an efficient particle scheme which allows us to parallelize the computation and then, after a suitable generalization of the scheme to the case of random inputs, we present a Galerkin reformulation of the particle dynamics, obtained by means of a generalized polynomial chaos approach, which allows the reconstruction of the kinetic distribution. As a consequence, the proposed particle-based scheme preserves the physical properties and the positivity of the distribution function also in the presence of a complex scattering in the transport equation of electrons. The impact of the uncertainty of the band gap and applied field on the electrical current is analyzed.
- [44] arXiv:2404.19616 [pdf, other]
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Title: Unified Framework of Forced Magnetic Reconnection and Alfvén ResonanceSubjects: Plasma Physics (physics.plasm-ph)
A unified linear theory that includes forced reconnection as a particular case of Alfv\'en resonance is presented. We consider a generalized Taylor problem in which a sheared magnetic field is subject to a time-dependent boundary perturbation oscillating at frequency $\omega_0$. By analyzing the asymptotic time response of the system, the theory demonstrates that the Alfv\'en resonance is due to the residues at the resonant poles, in the complex frequency plane, introduced by the boundary perturbation. Alfv\'en resonance transitions towards forced reconnection, described by the constant-psi regime for (normalized) times $t\gg S^{1/3}$, when the forcing frequency of the boundary perturbation is $\omega_0\ll S^{-1/3}$, allowing the coupling of the Alfv\'en resonances across the neutral line with the reconnecting mode, as originally suggested in [1]. Additionally, it is shown that even if forced reconnection develops for finite, albeit small, frequencies, the reconnection rate and reconnected flux are strongly reduced for frequencies $\omega_0\gg S^{-3/5}$.
- [45] arXiv:2404.19635 [pdf, other]
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Title: Thermal Fluid Closures and Pressure Anisotropies in Numerical Simulations of Plasma Wakefield AccelerationComments: The following article has been submitted to Physics of PlasmaSubjects: Plasma Physics (physics.plasm-ph); Accelerator Physics (physics.acc-ph); Computational Physics (physics.comp-ph)
We investigate the dynamics of plasma-based acceleration processes with collisionless particle dynamics and non negligible thermal effects. We aim at assessing the applicability of fluid-like models, obtained by suitable closure assumptions applied to the relativistic kinetic equations, thus not suffering of statistical noise, even in presence of a finite temperature. The work here presented focuses on the characterization of pressure anisotropies, which crucially depend on the adopted closure scheme, and hence are useful to discern the appropriate thermal fluid model. To this aim, simulation results of spatially resolved fluid models with different thermal closure assumptions are compared with the results of particle-in-cell (PIC) simulations at changing temperature and amplitude of plasma oscillations.
- [46] arXiv:2404.19636 [pdf, other]
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Title: Inverse Modeling of Bubble Size Dynamics for Interphase Mass Transfer and Gas Holdup in CO2 Bubble Column ReactorsSubjects: Fluid Dynamics (physics.flu-dyn)
The use of microbial gas fermentation for transforming captured CO2 into sustainable fuels and chemicals has been identified as a promising decarbonization pathway. To accelerate the scale-up of gaseous CO2 fermentation reactors, computational models need to predict gas-to-liquid mass transfer which requires capturing the bubble size dynamics, i.e. bubble breakup and coalescence. In this work, an inverse modeling approach is used to calibrate the breakup and coalescence closure models, that are used in the Multiple-Size-Group (MUSIG) population balance modeling (PBM). The calibration aims at replicating experimental results obtained in a CO2-air-water-coflowing bubble column reactor. Bayesian inference is used to account for noise in the experimental dataset and bias in the simulation results. The estimated simulation bias also allows identifying the best-performing closure models irrespective of the model parameters used. The calibration results suggest that the breakage rate is underestimated by one order of magnitude in two different breakup modeling approaches.
- [47] arXiv:2404.19641 [pdf, ps, other]
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Title: Fast and label-free 3D virtual H&E histology via active modulation-assisted dynamic full-field OCTAuthors: Zichen Yin, Bin He, Yuzhe Ying, Shuwei Zhang, Panqi Yang, Zhengyu Chen, Zhangwei Hu, Yejiong Shi, Ruizhi Xue, Chengming Wang, Shu Wang, Guihuai Wang, Ping XueSubjects: Medical Physics (physics.med-ph); Biological Physics (physics.bio-ph); Optics (physics.optics)
Pathological features are the gold standard for tumor diagnosis, guiding treatment and prognosis. However, standard histopathological process is labor-intensive and time-consuming, while frozen sections have lower accuracy. Dynamic full-field optical coherence tomography (D-FFOCT) offers rapid histologic information by measuring the subcellular dynamics of fresh, unprocessed tissues. However, D-FFOCT images suffer from abrupt shifts in hue and brightness, which is confusing for pathologists and diminish their interpretability and reliability. Here, we present active phase modulation-assisted D-FFOCT (APMD-FFOCT) to improve the imaging stability and enhance the contrast of static tissues. This enables us to further employ an unsupervised deep learning to convert APMD-FFOCT images into virtual hematoxylin and eosin (H&E) stained images for the first time. Three-dimensional (3D) virtual H&E-stained images have been obtained at a scanning rate of 1 frame per second, as demonstrated in cancer diagnosis for human central nervous system and breast. The results prove that this new method will play a unique and important role in intraoperative histology.
- [48] arXiv:2404.19665 [pdf, other]
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Title: ATOMMIC: An Advanced Toolbox for Multitask Medical Imaging Consistency to facilitate Artificial Intelligence applications from acquisition to analysis in Magnetic Resonance ImagingSubjects: Medical Physics (physics.med-ph); Artificial Intelligence (cs.AI); Mathematical Software (cs.MS); Software Engineering (cs.SE); Mathematical Physics (math-ph)
AI is revolutionizing MRI along the acquisition and processing chain. Advanced AI frameworks have been developed to apply AI in various successive tasks, such as image reconstruction, quantitative parameter map estimation, and image segmentation. Existing frameworks are often designed to perform tasks independently or are focused on specific models or datasets, limiting generalization. We introduce ATOMMIC, an open-source toolbox that streamlines AI applications for accelerated MRI reconstruction and analysis. ATOMMIC implements several tasks using DL networks and enables MultiTask Learning (MTL) to perform related tasks integrated, targeting generalization in the MRI domain. We first review the current state of AI frameworks for MRI through a comprehensive literature search and by parsing 12,479 GitHub repositories. We benchmark 25 DL models on eight publicly available datasets to present distinct applications of ATOMMIC on accelerated MRI reconstruction, image segmentation, quantitative parameter map estimation, and joint accelerated MRI reconstruction and image segmentation utilizing MTL. Our findings demonstrate that ATOMMIC is the only MTL framework with harmonized complex-valued and real-valued data support. Evaluations on single tasks show that physics-based models, which enforce data consistency by leveraging the physical properties of MRI, outperform other models in reconstructing highly accelerated acquisitions. Physics-based models that produce high reconstruction quality can accurately estimate quantitative parameter maps. When high-performing reconstruction models are combined with robust segmentation networks utilizing MTL, performance is improved in both tasks. ATOMMIC facilitates MRI reconstruction and analysis by standardizing workflows, enhancing data interoperability, integrating unique features like MTL, and effectively benchmarking DL models.
- [49] arXiv:2404.19670 [pdf, other]
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Title: Magnetic trapping of an ultracold $^{39}$K-$^{40}$K mixture with a versatile potassium laser systemComments: 15 pages, 7 figuresSubjects: Atomic Physics (physics.atom-ph)
We present a dual isotope magneto-optical trap (MOT), simultaneous sub-Doppler laser cooling, and magnetic trapping of a spin-polarized $^{39}$K-$^{40}$K Bose-Fermi mixture realized in a single-chamber setup with an unenriched potassium dispenser as the source of atoms. We are able to magnetically confine more than $2.2\times10^5$ fermions ($F=9/2\,m_F=9/2$) and $1.4\times10^7$ bosons ($F=2\,m_F=2$) with a lifetime exceeding 1.2 s. For this work, we have developed a versatile laser tailored for sub-Doppler cooling of all naturally occurring potassium isotopes and their mixtures. This laser system incorporates innovative features, such as the capability to select an isotope by activating or deactivating specific acousto-optic modulators that control the light seeding tapered amplifiers. Switching between isotopes takes $\sim$1 $\mathrm{\mu}$s without any mechanical adjustment of the components. As a final step in characterizing the laser system, we demonstrate sub-Doppler cooling of $^{41}$K.
- [50] arXiv:2404.19701 [pdf, other]
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Title: Dynamics of particle aggregation in dewetting films of complex liquidsComments: 39 pages, 18 figuresSubjects: Fluid Dynamics (physics.flu-dyn); Soft Condensed Matter (cond-mat.soft)
We consider the dynamic wetting and dewetting processes of films and droplets of complex liquids on planar surfaces, focusing on the case of colloidal suspensions, where the particle interactions can be sufficiently attractive to cause agglomeration of the colloids within the film. This leads to an interesting array of dynamic behaviours within the liquid and of the liquid-air interface. Incorporating concepts from thermodynamics and using the thin-film approximation, we construct a model consisting of a pair of coupled partial differential equations that represent the evolution of the liquid film and the effective colloidal height profiles. We determine the relevant phase behaviour of the uniform system, including finding associated binodal and spinodal curves, helping to uncover how the emerging behaviour depends on the particle interactions. Performing a linear stability analysis of our system enables us to identify parameter regimes where agglomerates form, which we independently confirm through numerical simulations and continuation of steady states, to construct bifurcation diagrams. We obtain various dynamics such as uniform colloidal profiles in an unstable situation evolving into agglomerates and thus elucidate the interplay between dewetting and particle aggregation in complex liquids on surfaces.
- [51] arXiv:2404.19711 [pdf, other]
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Title: Elevating electron energy gain and betatron X-ray emission in proton-driven wakefield accelerationSubjects: Accelerator Physics (physics.acc-ph)
The long proton beams present at CERN have the potential to evolve into a train of microbunches through the self-modulation instability process. The resonant wakefield generated by a periodic train of proton microbunches can establish a high acceleration field within the plasma, facilitating electron acceleration. This paper investigates the impact of plasma density on resonant wakefield excitation, thus influencing acceleration of a witness electron bunch and its corresponding betatron radiation within the wakefield. Various scenarios involving different plasma densities are explored through particle-in-cell simulations. The peak wakefield in each scenario is calculated by considering a long pre-modulated proton driver with a fixed peak current. Subsequently, the study delves into the witness beam acceleration in the wakefield and its radiation emission. Elevated plasma density increases both the number of microbunches and the accelerating gradient of each microbunch, consequently resulting in heightened resonant wakefield. Nevertheless, the scaling is disrupted by the saturation of the resonant wakefield due to the nonlinearities. The simulation results reveal that at high plasma densities an intense and broadband radiation spectrum extending into the domain of the hard X-rays and gamma rays is generated. Furthermore, in such instances, the energy gain of the witness beam is significantly enhanced. The impact of wakefield on the witness energy gain and the corresponding radiation spectrum is clearly evident at extremely elevated densities.
- [52] arXiv:2404.19716 [pdf, ps, other]
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Title: Controlled Spalling of Single Crystal 4H-SiC Bulk SubstratesAuthors: Connor P Horn, Christina Wicker, Antoni Wellisz, Cyrus Zeledon, Pavani Vamsi Krishna Nittala, F Joseph Heremans, David D Awschalom, Supratik GuhaComments: 13 pages (+6 supporting), 6 figures (+5 supporting)Subjects: Applied Physics (physics.app-ph); Materials Science (cond-mat.mtrl-sci)
We detail several scientific and engineering innovations which enable the controlled spalling of 10 - 50 micron thick films of single crystal 4H silicon carbide (4H-SiC) from bulk substrates. 4H-SiC's properties, including high thermal conductivity and a wide bandgap, make it an ideal candidate for high-temperature, high-voltage power electronic devices. Moreover, 4H-SiC has been shown to be an excellent host of solid-state atomic defect qubits for quantum computing and quantum networking. Because 4H-SiC single crystal substrates are expensive (due to long growth times and limited yield), techniques for removal and transfer of layers in the tens-of-microns thickness range are highly desirable for substrate reuse and heterogenous integration of separated layers. In this work we utilize novel approaches for stressor layer thickness control and spalling crack initiation to demonstrate controlled spalling of 4H-SiC, the highest fracture toughness material spalled to date. Additionally, we demonstrate substrate re-use, bonding of the spalled films to carrier substrates, and explore the spin coherence of the spalled films. In preliminary studies we are able to achieve coherent spin control of neutral divacancy ($VV^{0}$) qubit ensembles and measure a spin T2* of 0.581 $\mu$s in such spalled films.
- [53] arXiv:2404.19734 [pdf, other]
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Title: Replica-assisted super-resolution fluorescence imaging in scattering mediaComments: 6 pages, 3 figures in the main textSubjects: Optics (physics.optics)
Far-field super-resolution fluorescence microscopy has been rapidly developed for applications ranging from cell biology to nanomaterials. However, it remains a significant challenge to achieve super-resolution imaging at depth in opaque materials. In this study, we present a super-resolution microscopy technique for imaging hidden fluorescent objects through scattering media, started by exploiting the inherent object replica generation arising from the memory effect, i.e. the seemingly informationless emission speckle can be regarded as a random superposition of multiple object copies. Inspired by the concept of super-resolution optical fluctuation imaging, we use temporally-fluctuating speckles to excite fluorescent signals and perform high-order cumulant analysis on the fluctuation, which can not only improve the image resolution, but also increase the speckle contrast to isolate only the bright object replicas. A super-resolved image can be finally retrieved by simply unmixing the sparsely distributed replicas with their location map. This methodology allows to overcome scattering and achieve robust super-resolution fluorescence imaging, circumventing the need of heavy computational steps.
Cross-lists for Wed, 1 May 24
- [54] arXiv:2404.18980 (cross-list from econ.GN) [pdf, other]
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Title: The Impact of COVID-19 on Co-authorship and Economics Scholars' ProductivitySubjects: General Economics (econ.GN); Physics and Society (physics.soc-ph); Applications (stat.AP)
The COVID-19 pandemic has disrupted traditional academic collaboration patterns, prompting a unique opportunity to analyze the influence of peer effects and coauthorship dynamics on research output. Using a novel dataset, this paper endeavors to make a first cut at investigating the role of peer effects on the productivity of economics scholars, measured by the number of publications, in both pre-pandemic and pandemic times. Results show that peer effect is significant for the pre-pandemic time but not for the pandemic time. The findings contribute to our understanding of how research collaboration influences knowledge production and may help guide policies aimed at fostering collaboration and enhancing research productivity in the academic community.
- [55] arXiv:2404.18992 (cross-list from hep-ph) [pdf, other]
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Title: Unifying Simulation and Inference with Normalizing FlowsComments: 11 pages, 7 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); Data Analysis, Statistics and Probability (physics.data-an); Instrumentation and Detectors (physics.ins-det); Machine Learning (stat.ML)
There have been many applications of deep neural networks to detector calibrations and a growing number of studies that propose deep generative models as automated fast detector simulators. We show that these two tasks can be unified by using maximum likelihood estimation (MLE) from conditional generative models for energy regression. Unlike direct regression techniques, the MLE approach is prior-independent and non-Gaussian resolutions can be determined from the shape of the likelihood near the maximum. Using an ATLAS-like calorimeter simulation, we demonstrate this concept in the context of calorimeter energy calibration.
- [56] arXiv:2404.19005 (cross-list from quant-ph) [pdf, other]
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Title: Fault-tolerant compiling of classically hard IQP circuits on hypercubesAuthors: Dominik Hangleiter, Marcin Kalinowski, Dolev Bluvstein, Madelyn Cain, Nishad Maskara, Xun Gao, Aleksander Kubica, Mikhail D. Lukin, Michael J. GullansComments: 27 + 20 pages, 13 FiguresSubjects: Quantum Physics (quant-ph); Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Computational Complexity (cs.CC); Atomic Physics (physics.atom-ph)
Realizing computationally complex quantum circuits in the presence of noise and imperfections is a challenging task. While fault-tolerant quantum computing provides a route to reducing noise, it requires a large overhead for generic algorithms. Here, we develop and analyze a hardware-efficient, fault-tolerant approach to realizing complex sampling circuits. We co-design the circuits with the appropriate quantum error correcting codes for efficient implementation in a reconfigurable neutral atom array architecture, constituting what we call a fault-tolerant compilation of the sampling algorithm. Specifically, we consider a family of $[[2^D , D, 2]]$ quantum error detecting codes whose transversal and permutation gate set can realize arbitrary degree-$D$ instantaneous quantum polynomial (IQP) circuits. Using native operations of the code and the atom array hardware, we compile a fault-tolerant and fast-scrambling family of such IQP circuits in a hypercube geometry, realized recently in the experiments by Bluvstein et al. [Nature 626, 7997 (2024)]. We develop a theory of second-moment properties of degree-$D$ IQP circuits for analyzing hardness and verification of random sampling by mapping to a statistical mechanics model. We provide evidence that sampling from hypercube IQP circuits is classically hard to simulate and analyze the linear cross-entropy benchmark (XEB) in comparison to the average fidelity. To realize a fully scalable approach, we first show that Bell sampling from degree-$4$ IQP circuits is classically intractable and can be efficiently validated. We further devise new families of $[[O(d^D),D,d]]$ color codes of increasing distance $d$, permitting exponential error suppression for transversal IQP sampling. Our results highlight fault-tolerant compiling as a powerful tool in co-designing algorithms with specific error-correcting codes and realistic hardware.
- [57] arXiv:2404.19023 (cross-list from quant-ph) [pdf, other]
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Title: Sign problem in tensor network contractionSubjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); Strongly Correlated Electrons (cond-mat.str-el); Computational Physics (physics.comp-ph)
We investigate how the computational difficulty of contracting tensor networks depends on the sign structure of the tensor entries. Using results from computational complexity, we observe that the approximate contraction of tensor networks with only positive entries has lower complexity. This raises the question how this transition in computational complexity manifests itself in the hardness of different contraction schemes. We pursue this question by studying random tensor networks with varying bias towards positive entries. First, we consider contraction via Monte Carlo sampling, and find that the transition from hard to easy occurs when the entries become predominantly positive; this can be seen as a tensor network manifestation of the Quantum Monte Carlo sign problem. Second, we analyze the commonly used contraction based on boundary tensor networks. Its performance is governed by the amount of correlations (entanglement) in the tensor network. Remarkably, we find that the transition from hard to easy (i.e., from a volume law to a boundary law scaling of entanglement) occurs already for a slight bias towards a positive mean, and the earlier the larger the bond dimension is. This is in contrast to both expectations and the behavior found in Monte Carlo contraction. We gain further insight into this early transition from the study of an effective statmech model. Finally, we investigate the computational difficulty of computing expectation values of tensor network wavefunctions, i.e., PEPS, where we find that the complexity of entanglement-based contraction always remains low. We explain this by providing a local transformation which maps PEPS expectation values to a positive-valued tensor network. This not only provides insight into the origin of the observed boundary law entanglement scaling, but also suggests new approaches towards PEPS contraction based on positive decompositions.
- [58] arXiv:2404.19027 (cross-list from quant-ph) [pdf, other]
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Title: Better Optimization of Variational Quantum Eigensolvers by combining the Unitary Block Optimization Scheme with Classical Post-ProcessingComments: 16 pages, 10 figuresSubjects: Quantum Physics (quant-ph); Computational Physics (physics.comp-ph)
Variational Quantum Eigensolvers (VQE) are a promising approach for finding the classically intractable ground state of a Hamiltonian. The Unitary Block Optimization Scheme (UBOS) is a state-of-the-art VQE method which works by sweeping over gates and finding optimal parameters for each gate in the environment of other gates. UBOS improves the convergence time to the ground state by an order of magnitude over Stochastic Gradient Descent (SGD). It nonetheless suffers in both rate of convergence and final converged energies in the face of highly noisy expectation values coming from shot noise. Here we develop two classical post-processing techniques which improve UBOS especially when measurements have large noise. Using Gaussian Process Regression (GPR) we generate artificial augmented data using original data from the quantum computer to reduce the overall error when solving for the improved parameters. Using Double Robust Optimization plus Rejection (DROPR), we prevent outlying data which are atypically noisy from resulting in a a particularly erroneous single optimization step thereby increasing robustness against noisy measurements. Combining these techniques further reduces the final relative error that UBOS reaches by a factor of three without adding additional quantum measurement or sampling overhead. This work further demonstrates that developing techniques which use classical resources to post-process quantum measurement results can significantly improve VQE algorithms.
- [59] arXiv:2404.19101 (cross-list from astro-ph.GA) [pdf, other]
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Title: Neutral hydrogen filaments in interstellar media: Are they physical?Journal-ref: Rev. Mod. Plasma Phys. 8, 21 (2024)Subjects: Astrophysics of Galaxies (astro-ph.GA); Plasma Physics (physics.plasm-ph)
The trending term "filament" is extensively used in the interstellar medium (ISM) and the star formation community, and is believed to be one of the most important objects that gauge molecular cloud and star formation. However, the physical definition of these ubiquitous, elongated, high contrast features is poorly defined and still actively debated. Despite the absence of a unified consensus, filaments are believed to be involved in many important physical processes from galaxy structure formation to the emergence of protostellar objects. Therefore, understanding how filaments form, what constrains their growth, and their general physical properties, are extremely important for theorists and observers who study the dynamics of the ISM and consequent star formations. This review serves as a collection of the community's views and develops the concept of "filaments" in the context of the ISM and star-forming clouds. Observationally, filaments are seen across the entire sky and often carry an aspect ratio of the order of hundreds. In the context of the ISM, filaments are believed to form by stretching and tearing from magnetized ISM turbulence. ISM filaments are subjected to heating and cooling phases, and are likely to be magnetically aligned. Cold clouds are formed inside ISM due to turbulence instability. This review updates the understanding of ISM filaments in the community.
- [60] arXiv:2404.19103 (cross-list from astro-ph.SR) [pdf, other]
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Title: Tayler Instability RevisitedSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
Tayler instability of toroidal magnetic fields $B_\phi$ is broadly invoked as a trigger for turbulence and angular momentum transport in stars. This paper presents a systematic revision of the linear stability analysis for a rotating, magnetized, and stably stratified star. For plausible configurations of $B_\phi$, instability requires diffusive processes: viscosity, magnetic diffusivity, or thermal/compositional diffusion. Our results reveal a new physical picture, demonstrating how different diffusive effects independently trigger instability of two types of waves in the rotating star: magnetostrophic waves and inertial waves. It develops via overstability of the waves, whose growth rate sharply peaks at some characteristic wavenumbers. We determine instability conditions for each wave branch and find the characteristic wavenumbers. The results are qualitatively different for stars with magnetic Prandtl number $Pm\ll 1$ (e.g. the Sun) and $Pm\gg 1$ (e.g. protoneutron stars). The parameter dependence of unstable modes suggests a non-universal scaling of the possible Tayler-Spruit dynamo.
- [61] arXiv:2404.19131 (cross-list from astro-ph.EP) [pdf, other]
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Title: Capillary processes in extraterrestrial contextsAuthors: Daniel Cordier, Gerard Liger-Belair, David A. Bonhommeau, Thomas Seon, Thomas Appere, Nathalie CarrascoComments: This paper is accepted in "Journal of Geophysical Research: Planet". Data and softwares are publicly available at this https URLSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Geophysics (physics.geo-ph)
The Earth is no longer the only known celestial body containing one or more liquid phases. The Cassini spacecraft has discovered seas of hydrocarbons at the surface of Titan, while a series of corroborating evidences argue in favour of the existence of an aqueous ocean beneath the icy crust of several moons. Capillarity embraces a family of physical processes occurring at the free surface of a liquid. These phenomena depend on the liquid properties and on the local planetary conditions. Capillarity may have important direct or indirect implications on the geoscientific and astrobiological points of view. In this paper, we discuss capillarity physics among solar system objects and expected consequences for planetary science.
- [62] arXiv:2404.19137 (cross-list from cond-mat.str-el) [pdf, other]
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Title: Thermoelectric transport properties of the quasi-one-dimensional dimer-Mott insulator $β'$-(BEDT-TTF)$_2$ICl$_2$Comments: 7 pages, 5 figures. Accepted for publication in Phys. Rev. MaterialsSubjects: Strongly Correlated Electrons (cond-mat.str-el); Materials Science (cond-mat.mtrl-sci); Soft Condensed Matter (cond-mat.soft); Chemical Physics (physics.chem-ph)
Low-dimensional materials, in which the electronic and transport properties are drastically modified in comparison to those of three-dimensional bulk materials, yield a key class of thermoelectric materials with high conversion efficiency. Among such materials, the organic compounds may serve peculiar properties owing to their unique molecular-based low-dimensional structures with highly anisotropic molecular orbitals. Here we present the thermoelectric transport properties of the quasi-one-dimensional dimer-Mott insulator $\beta'$-(BEDT-TTF)$_2$ICl$_2$, where BEDT-TTF stands for bis(ethylenedithio)-tetrathiafulvalene. We find that the thermopower exhibits typical activation-type temperature variation expected for insulators but its absolute value is anomalously large compared to the expected value from the activation-type temperature dependence of the electrical resistivity. Successively, the Jonker-plot analysis, in which the thermopower is usually scaled by the logarithm of the resistivity, shows an unusual relation among such transport quantities. We discuss a role of the low dimensionality for the enhanced thermopower along with recent observations of such a large thermopower in several low-dimensional materials.
- [63] arXiv:2404.19153 (cross-list from cond-mat.mtrl-sci) [pdf, other]
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Title: Room temperature realization of artificial chiral magnets with reprogrammable magnon nonreciprocity at zero fieldSubjects: Materials Science (cond-mat.mtrl-sci); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Applied Physics (physics.app-ph)
Chiral magnets are materials which possess unique helical arrangements of magnetic moments, which give rise to nonreciprocal transport and fascinating physics phenomena. On the one hand, their exploration is guided by the prospects of unconventional signal processing, computation schemes and magnetic memory. On the other hand, progress in applications is hindered by the challenging materials synthesis, limited scalability and typically low critical temperature. Here, we report the creation and exploration of artificial chiral magnets (ACMs) at room temperature. By employing a mass production compatible deposition technology, we synthesize ACMs, which consist of helical Ni surfaces on central cylinders. Using optical microscopy, we reveal nonreciprocal magnon transport at GHz frequencies. It is controlled by programmable toroidal moments which result from the ACM's geometrical handedness and field-dependent spin chirality. We present materials-by-design rules which optimize the helically curved ferromagnets for 3D nonreciprocal transport at room temperature and zero magnetic field.
- [64] arXiv:2404.19167 (cross-list from eess.IV) [pdf, ps, other]
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Title: Advancing low-field MRI with a universal denoising imaging transformer: Towards fast and high-quality imagingAuthors: Zheren Zhu, Azaan Rehman, Xiaozhi Cao, Congyu Liao, Yoo Jin Lee, Michael Ohliger, Hui Xue, Yang YangSubjects: Image and Video Processing (eess.IV); Medical Physics (physics.med-ph)
Recent developments in low-field (LF) magnetic resonance imaging (MRI) systems present remarkable opportunities for affordable and widespread MRI access. A robust denoising method to overcome the intrinsic low signal-noise-ratio (SNR) barrier is critical to the success of LF MRI. However, current data-driven MRI denoising methods predominantly handle magnitude images and rely on customized models with constrained data diversity and quantity, which exhibit limited generalizability in clinical applications across diverse MRI systems, pulse sequences, and organs. In this study, we present ImT-MRD: a complex-valued imaging transformer trained on a vast number of clinical MRI scans aiming at universal MR denoising at LF systems. Compared with averaging multiple-repeated scans for higher image SNR, the model obtains better image quality from fewer repetitions, demonstrating its capability for accelerating scans under various clinical settings. Moreover, with its complex-valued image input, the model can denoise intermediate results before advanced post-processing and prepare high-quality data for further MRI research. By delivering universal and accurate denoising across clinical and research tasks, our model holds great promise to expedite the evolution of LF MRI for accessible and equal biomedical applications.
- [65] arXiv:2404.19181 (cross-list from astro-ph.HE) [pdf, other]
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Title: Low-energy Injection and Nonthermal Particle Acceleration in Relativistic Magnetic TurbulenceComments: 11 pages, 7 figures, 1 animation, Submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
Relativistic magnetic turbulence has been proposed as a process for producing nonthermal particles in high-energy astrophysics. The particle energization may be contributed by both magnetic reconnection and turbulent fluctuations, but their interplay is poorly understood. It has been suggested that during magnetic reconnection the parallel electric field dominates the particle acceleration up to the lower bound of the power-law particle spectrum, but recent studies show that electric fields perpendicular to the magnetic field can play an important, if not dominant role. In this study, we carry out fully kinetic particle-in-cell simulations of magnetically dominated decaying turbulence in a relativistic pair plasma. For a fixed magnetization parameter $\sigma_0 = 20$, we find that the injection energy~$\varepsilon_{\rm inj}$ converges with increasing domain size to~$\varepsilon_{\rm inj} \simeq 10 \, m_ec^2$. In contrast, the power-law index, the cut-off energy, and the power-law extent increase steadily with domain size. We trace a large number of particles and evaluate the contributions of the work done by the parallel ($W_\parallel$) and perpendicular ($W_\perp$) electric fields during both the injection phase and the post-injection phase. We find that during the injection phase, the $W_\perp$ contribution increases with domain size, suggesting that it may eventually dominate injection for a sufficiently large domain. In contrast, both components contribute equally during the post-injection phase, insensitive to the domain size. For high energy ($\varepsilon \gg \varepsilon_{\rm inj}$) particles, $W_\perp$ dominates the subsequent energization. These findings may improve our understanding of nonthermal particles and their emissions in astrophysical plasmas.
- [66] arXiv:2404.19193 (cross-list from cond-mat.mtrl-sci) [pdf, ps, other]
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Title: Tunable Collective Excitations in Epitaxial Perovskite NickelatesAuthors: Mengxia Sun, Xu He, Mingyao Chen, Chi Sin Tang, Xiongfang Liu, Liang Dai, Jishan Liu, Zhigang Zeng, Shuo Sun, Mark B.H. Breese, Chuanbing Cai, Yingge Du, Le Wang, Andrew T. S. Wee, Xinmao YinSubjects: Materials Science (cond-mat.mtrl-sci); Optics (physics.optics); Plasma Physics (physics.plasm-ph)
The formation of plasmons through the collective excitation of charge density has generated intense discussions, offering insights to fundamental sciences and potential applications. While the underlying physical principles have been well-established, the effects of multibody interactions and orbital hybridization on plasmonic dynamics remain understudied. In this work, we present the observation of conventional metallic and correlated plasmons in epitaxial La1-xSrxNiO3 (LSNO) films with varying Sr doping concentrations (x = 0, 0.125, 0.25), unveiling their intriguing evolution. Unlike samples at other doping concentrations, the x = 0.125 intermediate doping sample does not exhibit the correlated plasmons despite showing high optical conductivity. Through experimental investigation using spectroscopic ellipsometry and X-ray absorption spectroscopy, that is further supported by theoretical calculations, the O2p-Ni3d orbital hybridization for x = 0.125 is found to be significantly enhanced, alongside a considerable weakening of its effective correlation U*. These factors account for the absence of correlated plasmons and the high optical conductivity observed in LSNO (0.125). Our findings highlight the significant impact of orbital hybridization on the electronic structures and the formation of quasiparticles in strongly correlated systems, thereby marking a notable advancement in plasmonics, emphasizing LSNO's compelling potential as a substitute material in optoelectronic devices.
- [67] arXiv:2404.19195 (cross-list from eess.SY) [pdf, ps, other]
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Title: Evaluation of Thermal Performance of a Wick-free Vapor Chamber in Power Electronics CoolingAuthors: Arani Mukhopadhyay (1), Anish Pal (1), Congbo Bao (2), Mohamad Jafari Gukeh (1), Sudip K. Mazumder (2), Constantine M. Megaridis (1) ((1) Mechanical and Industrial Engineering, University of Illinois Chicago, IL, US. (2) Electrical and Computer Engineering, University of Illinois Chicago, IL, US.)Comments: Presented at IEEE ITherm (Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems) 2023, Orlando FL. Corresponding author: cmm@uic.eduSubjects: Systems and Control (eess.SY); Hardware Architecture (cs.AR); Applied Physics (physics.app-ph)
Efficient thermal management in high-power electronics cooling can be achieved using phase-change heat transfer devices, such as vapor chambers. Traditional vapor chambers use wicks to transport condensate for efficient thermal exchange and to prevent "dry-out" of the evaporator. However, wicks in vapor chambers present significant design challenges arising out of large pressure drops across the wicking material, which slows down condensate transport rates and increases the chances for dry-out. Thicker wicks add to overall thermal resistance, while deterring the development of thinner devices by limiting the total thickness of the vapor chamber. Wickless vapor chambers eliminate the use of metal wicks entirely, by incorporating complementary wettability-patterned flat plates on both the evaporator and the condenser side. Such surface modifications enhance fluid transport on the evaporator side, while allowing the chambers to be virtually as thin as imaginable, thereby permitting design of thermally efficient thin electronic cooling devices. While wick-free vapor chambers have been studied and efficient design strategies have been suggested, we delve into real-life applications of wick-free vapor chambers in forced air cooling of high-power electronics. An experimental setup is developed wherein two Si-based MOSFETs of TO-247-3 packaging having high conduction resistance, are connected in parallel and switched at 100 kHz, to emulate high frequency power electronics operations. A rectangular copper wick-free vapor chamber spreads heat laterally over a surface 13 times larger than the heating area. This chamber is cooled externally by a fan that circulates air at room temperature. The present experimental setup extends our previous work on wick-free vapor chambers, while demonstrating the effectiveness of low-cost air cooling in vapor-chamber enhanced high-power electronics applications.
- [68] arXiv:2404.19201 (cross-list from eess.IV) [pdf, other]
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Title: Global Search Optics: Automatically Exploring Optimal Solutions to Compact Computational Imaging SystemsComments: The source code will be made publicly available at this https URLSubjects: Image and Video Processing (eess.IV); Computer Vision and Pattern Recognition (cs.CV); Robotics (cs.RO); Optics (physics.optics)
The popularity of mobile vision creates a demand for advanced compact computational imaging systems, which call for the development of both a lightweight optical system and an effective image reconstruction model. Recently, joint design pipelines come to the research forefront, where the two significant components are simultaneously optimized via data-driven learning to realize the optimal system design. However, the effectiveness of these designs largely depends on the initial setup of the optical system, complicated by a non-convex solution space that impedes reaching a globally optimal solution. In this work, we present Global Search Optics (GSO) to automatically design compact computational imaging systems through two parts: (i) Fused Optimization Method for Automatic Optical Design (OptiFusion), which searches for diverse initial optical systems under certain design specifications; and (ii) Efficient Physic-aware Joint Optimization (EPJO), which conducts parallel joint optimization of initial optical systems and image reconstruction networks with the consideration of physical constraints, culminating in the selection of the optimal solution. Extensive experimental results on the design of three-piece (3P) sphere computational imaging systems illustrate that the GSO serves as a transformative end-to-end lens design paradigm for superior global optimal structure searching ability, which provides compact computational imaging systems with higher imaging quality compared to traditional methods. The source code will be made publicly available at https://github.com/wumengshenyou/GSO.
- [69] arXiv:2404.19261 (cross-list from cs.LG) [pdf, other]
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Title: High dimensional analysis reveals conservative sharpening and a stochastic edge of stabilitySubjects: Machine Learning (cs.LG); Optimization and Control (math.OC); Statistics Theory (math.ST); Data Analysis, Statistics and Probability (physics.data-an)
Recent empirical and theoretical work has shown that the dynamics of the large eigenvalues of the training loss Hessian have some remarkably robust features across models and datasets in the full batch regime. There is often an early period of progressive sharpening where the large eigenvalues increase, followed by stabilization at a predictable value known as the edge of stability. Previous work showed that in the stochastic setting, the eigenvalues increase more slowly - a phenomenon we call conservative sharpening. We provide a theoretical analysis of a simple high-dimensional model which shows the origin of this slowdown. We also show that there is an alternative stochastic edge of stability which arises at small batch size that is sensitive to the trace of the Neural Tangent Kernel rather than the large Hessian eigenvalues. We conduct an experimental study which highlights the qualitative differences from the full batch phenomenology, and suggests that controlling the stochastic edge of stability can help optimization.
- [70] arXiv:2404.19298 (cross-list from astro-ph.IM) [pdf, other]
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Title: Study of bound and resonant states of NS molecule in the R-matrix approachComments: 7 pages, 11 figuresJournal-ref: J. Phys. B: At. Mol. Opt. Phys. 55 (2022) 235202 (9pp)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Atomic Physics (physics.atom-ph)
The bound and resonance states along with corresponding autoionization widths for nitrogen sulphide (NS) molecule are determined using electron NS$^+$ cation scattering calculations. The calculations are performed for $^2{\Sigma}^+$, $^2{\Pi}$ and $^2\Delta$ total symmetries using the ab initio R-matrix method for both bound and continuum states. Calculations are performed on a grid of 106 points for internuclear separations between 1.32 and 3 $\AA$. The resonance states yield dissociative potential curves which, when considered together with their widths, provide input for models of different electron-cation collision processes including dissociative recombination, and rotational and vibrational excitation. Curves and couplings which will lead directly to dissociative recombination are identified.
- [71] arXiv:2404.19302 (cross-list from astro-ph.IM) [pdf, other]
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Title: Dissociative recombination of the CH$^+$ molecular ion at low energyComments: 8 pages, 8 figuresJournal-ref: J. Phys. B: At. Mol. Opt. Phys. 51 (2018) 104002 (8pp)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Atomic Physics (physics.atom-ph); Plasma Physics (physics.plasm-ph)
The reactive collisions of the CH$^+$ molecular ion with electrons is studied in the framework of the multichannel quantum defect theory, taking into account the contribution of the core-excited Rydberg states. In addition to the $X^1\Sigma^+$ ground state of the ion, we also consider the contribution to the dynamics of the $a^3\Pi$ and $A^1\Pi$ excited states of CH$^+$. Our results - in the case of the dissociative recombination in good agreement with the storage ring measurements - rely on decisive improvements - complete account of the ionisation channels and accurate evaluation of the reaction matrix - of a previously used model.
- [72] arXiv:2404.19313 (cross-list from quant-ph) [pdf, other]
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Title: High-precision chemical quantum sensing in flowing monodisperse microdropletsAuthors: Adrisha Sarkar, Zachary Jones, Madhur Parashar, Emanuel Druga, Amala Akkiraju, Sophie Conti, Pranav Krishnamoorthi, Srisai Nachuri, Parker Aman, Mohammad Hashemi, Nicholas Nunn, Marco Torelli, Benjamin Gilbert, Kevin R. Wilson, Olga Shenderova, Deepti Tanjore, Ashok AjoySubjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Applied Physics (physics.app-ph); Quantitative Methods (q-bio.QM)
We report on a novel flow-based method for high-precision chemical detection that integrates quantum sensing with droplet microfluidics. We deploy nanodiamond particles hosting fluorescent nitrogen vacancy defects as quantum sensors in flowing, monodisperse, picoliter-volume microdroplets containing analyte molecules. ND motion within these microcompartments facilitates close sensor-analyte interaction and mitigates particle heterogeneity. Microdroplet flow rates are rapid (upto 4cm/s) and with minimal drift. Pairing this controlled flow with microwave control of NV electronic spins, we introduce a new noise-suppressed mode of Optically Detected Magnetic Resonance that is sensitive to chemical analytes while resilient against experimental variations, achieving detection of analyte-induced signals at an unprecedented level of a few hundredths of a percent of the ND fluorescence. We demonstrate its application to detecting paramagnetic ions in droplets with simultaneously low limit-of-detection and low analyte volumes, in a manner significantly better than existing technologies. This is combined with exceptional measurement stability over >103s and across hundreds of thousands of droplets, while utilizing minimal sensor volumes and incurring low ND costs (<$0.70 for an hour of operation). Additionally, we demonstrate using these droplets as micro-confinement chambers by co-encapsulating ND quantum sensors with analytes, including single cells. This versatility suggests wide-ranging applications, like single-cell metabolomics and real-time intracellular measurements in bioreactors. Our work paves the way for portable, high-sensitivity, amplification-free, chemical assays with high throughput; introduces a new chemical imaging tool for probing chemical reactions in microenvironments; and establishes the foundation for developing movable, arrayed quantum sensors through droplet microfluidics.
- [73] arXiv:2404.19321 (cross-list from cond-mat.soft) [pdf, other]
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Title: Observation of strain-rate softening behavior in jammed granular mediaComments: 16 pages, 12 figuresSubjects: Soft Condensed Matter (cond-mat.soft); Applied Physics (physics.app-ph)
The strain-rate sensitivity of confined granular materials has been widely explored, with most findings exhibiting rate-strengthening behaviors. This study, however, reveals a distinct rate-softening behavior across a certain strain rate range based on triaxial tests on particle clusters of various materials with different surface properties, particle sizes, shapes, and stiffness. This softening effect is especially pronounced in the case of common rice particles. By examining the behavior of rice particles under different confining pressure and surface conditions, and directly measuring the frictional coefficient across various loading rates, we find that the reduction in surface frictional coefficient with the increasing strain rate predominantly contributes to this rate-softening behavior. This conclusion is validated by results from Finite Element Method (FEM) simulations. Additionally, we identify confining pressure as a critical factor regulating the normal stress between particles, and thereby enhancing frictional behavior. Rheometer tests reveal that the shear modulus exhibits a similar rate-softening trend. This study of rate-softening behavior in granular materials enhances our understanding of the mechanisms during their deformation under confining pressure. It also suggests that local inter-particle tribology significantly impacts overall granular behavior.
- [74] arXiv:2404.19366 (cross-list from cond-mat.mtrl-sci) [pdf, other]
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Title: Toward thermoelectric characterization of (nano)materials by in situ transmission electron microscopyComments: 12 pages, 5 figuresSubjects: Materials Science (cond-mat.mtrl-sci); Applied Physics (physics.app-ph); Instrumentation and Detectors (physics.ins-det)
We explore the possibility to perform an in situ transmission electron microscopy (TEM) thermoelectric characterization of materials. A differential heating element on a custom in situ TEM microchip allows to generate a temperature gradient across the studied materials, which are simultaneously measured electrically. A thermovoltage was induced in all studied devices, whose sign corresponds to the sign of the Seebeck coefficient of the tested materials. The results indicate that in situ thermoelectric TEM studies can help to profoundly understand the interplay between the thermoelectric properties on one side and the structure/composition of the materials down to the atomic level on the other side, including grain boundaries, dopants or crystal defects. We propose an improved in situ TEM microchip design, which should facilitate a full quantitative measurement of the induced temperature gradient, the electrical and thermal conductivities, as well as the Seebeck coefficient.
- [75] arXiv:2404.19373 (cross-list from quant-ph) [pdf, other]
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Title: Entanglement Signature of the Superradiant Quantum Phase TransitionSubjects: Quantum Physics (quant-ph); Mathematical Physics (math-ph); Optics (physics.optics)
Entanglement and quantum correlations between atoms are not usually considered key ingredients of the superradiant phase transition. Here we consider the Tavis-Cummings model, a solvable system of two-levels atoms, coupled with a single-mode quantized electromagnetic field. This system undergoes a superradiant phase transition, even in a finite-size framework, accompanied by a spontaneous symmetry breaking, and an infinite sequence of energy level crossings. We find approximated expressions for the ground state, its energy, and the position of the level crossings, valid in the limit of a very large number of photons with respect to that of the atoms. In that same limit, we find that the number of photons scales quadratically with the coupling strength, and linearly with the system size, providing a new insight into the superradiance phenomenon. Resorting to novel multipartite measures, we then demonstrate that this quantum phase transition is accompanied by a crossover in the quantum correlations and entanglement between the atoms (qubits). The latters therefore represent suited order parameters for this transition. Finally, we show that these properties of the quantum phase transition persist in the thermodynamic limit.
- [76] arXiv:2404.19440 (cross-list from cond-mat.mtrl-sci) [pdf, other]
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Title: Negative transit time in non-tunneling electron transmission through graphene multilayersComments: 9 pages, 6 figuresSubjects: Materials Science (cond-mat.mtrl-sci); Computational Physics (physics.comp-ph); Optics (physics.optics); Quantum Physics (quant-ph)
Attosecond dynamics of electron transmission through atomically-thin crystalline films is studied with an {\em ab initio} scattering theory. The temporal character of the electron propagation through graphene multilayers is traced to the band structure of bulk graphite: In the forbidden gaps the wave packet transit time $\tau_\mathrm{T}$ saturates with thickness and in the allowed bands $\tau_\mathrm{T}$ oscillates following transmission resonances. Hitherto unknown negative transit time due to in-plane scattering is discovered in monolayers of graphene, h-BN, and oxygen. Moreover, Wigner time delay is found to diverge at the scattering resonances caused by the emergence of secondary diffracted beams. This offers a way to manipulate the propagation timing of the wave packet without sacrificing the transmitted intensity. The spatial reshaping of the wave packet at the resonances may help elucidate details of the streaking by an inhomogeneous field at the surface.
- [77] arXiv:2404.19524 (cross-list from astro-ph.IM) [pdf, other]
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Title: DARWIN/XLZD: a future xenon observatory for dark matter and other rare interactionsAuthors: Laura BaudisComments: 7 pages, 10 figures. Accepted to appear in Nuc. Phys. B special issue "Nobel Symposium on Dark Matter" (NS 182)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)
The DARWIN/XLZD experiment is a next-generation dark matter detector with a multi-ten-ton liquid xenon time projection chamber at its core. Its principal goal will be to explore the experimentally accessible parameter space for Weakly Interacting Massive Particles (WIMPs) in a wide mass-range, until interactions of astrophysical neutrinos will become an irreducible background. The prompt scintillation light and the charge signals induced by particle interactions in the liquid xenon target will be observed by VUV-sensitive, ultra-low background photosensors. Besides its excellent sensitivity to WIMPs with masses above $\sim$5\,GeV, such a detector with its large mass, low-energy threshold and ultra-low background level will also be sensitive to other rare interactions, and in particular also to bosonic dark matter candidates with masses at the keV-scale. We present the detector concept, discuss the main sources of backgrounds, the technological challenges and some of the ongoing detector design and R&D efforts, as well as the large-scale demonstrators. We end by discussing the sensitivity to particle dark matter interactions.
- [78] arXiv:2404.19539 (cross-list from quant-ph) [pdf, other]
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Title: Path integral spin dynamics for quantum paramagnetsComments: 10 pages, 8 figuresSubjects: Quantum Physics (quant-ph); Materials Science (cond-mat.mtrl-sci); Computational Physics (physics.comp-ph)
A path integral method, combined with atomistic spin dynamics simulations, has been developed to calculate thermal quantum expectation values using a classical approach. In this study, we show how to treat Hamiltonians with non-linear terms, that are relevant for describing uniaxial anisotropies and mechanical constraints. These interactions can be expressed solely through quadratic terms of the spin operator along one axis, that can be identified with the quantisation axis.
- [79] arXiv:2404.19559 (cross-list from math.NA) [pdf, other]
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Title: Computational study of numerical flux schemes for mesoscale atmospheric flows in a Finite Volume frameworkComments: 22 pagesSubjects: Numerical Analysis (math.NA); Atmospheric and Oceanic Physics (physics.ao-ph)
We develop, and implement in a Finite Volume environment, a density-based approach for the Euler equations written in conservative form using density, momentum, and total energy as variables. Under simplifying assumptions, these equations are used to describe non-hydrostatic atmospheric flow. The well-balancing of the approach is ensured by a local hydrostatic reconstruction updated in runtime during the simulation to keep the numerical error under control. To approximate the solution of the Riemann problem, we consider four methods: Roe-Pike, HLLC, AUSM+-up and HLLC-AUSM. We assess our density-based approach and compare the accuracy of these four approximated Riemann solvers using two two classical benchmarks, namely the smooth rising thermal bubble and the density current.
- [80] arXiv:2404.19565 (cross-list from cond-mat.quant-gas) [pdf, other]
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Title: Towards a zero magnetic field environment for ultracold atoms experimentsAuthors: Chiara Rogora, Riccardo Cominotti, Cosetta Baroni, Diego Andreoni, Giacomo Lamporesi, Alessandro Zenesini, Gabriele FerrariComments: 8 pages, 7 figuresSubjects: Quantum Gases (cond-mat.quant-gas); Atomic Physics (physics.atom-ph)
The minimization of the magnetic field plays a crucial role in ultracold gas research. For instance, the contact interaction dominates all the other energy scales in the zero magnetic field limit, giving rise to novel quantum phases of matter. However, lowering magnetic fields well below the mG level is often challenging in ultracold gas experiments. In this article, we apply Landau-Zener spectroscopy to characterize and reduce the magnetic field on an ultracold gas of sodium atoms to a few tens of {\mu}G. The lowest magnetic field achieved here opens to observing novel phases of matter with ultracold spinor Bose gases.
- [81] arXiv:2404.19572 (cross-list from cond-mat.mtrl-sci) [pdf, other]
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Title: Self-assembling of multilayered polymorphs with ion beamsAuthors: Alexander Azarov, Cristian Radu, Augustinas Galeckas, Ionel Florinel Mercioniu, Adrian Cernescu, Vishnukanthan Venkatachalapathy, Edouard Monakhov, Flyura Djurabekova, Corneliu Ghica, Junlei Zhao, Andrej KuznetsovComments: 9 pages, 4 figure, under review, private communication for supplementary notesSubjects: Materials Science (cond-mat.mtrl-sci); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Computational Physics (physics.comp-ph)
Polymorphism contributes to the diversity of nature, so that even materials having identical chemical compositions exhibit variations in properties because of different lattice symmetries. Thus, if stacked together into multilayers, polymorphs may work as an alternative approach to the sequential deposition of layers with different chemical compositions. However, selective polymorph crystallization during conventional thin film synthesis is not trivial; e.g. opting for step-like changes of temperature and/or pressure correlated with switching from one polymorph to another during synthesis is tricky, since it may cause degradation of the structural quality. In the present work, applying the disorder-induced ordering approach we fabricated such multilayered polymorph structures using ion beams. We show that during ion irradiation of gallium oxide, the dynamic annealing of disorder may be tuned towards self-assembling of several polymorph interfaces, consistently with theoretical modelling. Specifically, we demonstrated multilayers with two polymorph interface repetitions obtained in one ion beam assisted fabrication step. Importantly, single crystal structure of the polymorphs was maintained in between interfaces exhibiting repeatable crystallographic relationships, correlating with optical cross-sectional maps. This data paves the way for enhancing functionalities in materials with not previously thought capabilities of ion beam technology.
- [82] arXiv:2404.19589 (cross-list from astro-ph.IM) [pdf, other]
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Title: Acceptance Tests of more than 10 000 Photomultiplier Tubes for the multi-PMT Digital Optical Modules of the IceCube UpgradeAuthors: R. Abbasi, M. Ackermann, J. Adams, S. K. Agarwalla, J. A. Aguilar, M. Ahlers, J.M. Alameddine, N. M. Amin, K. Andeen, C. Argüelles, Y. Ashida, S. Athanasiadou, L. Ausborm, S. N. Axani, X. Bai, A. Balagopal V., M. Baricevic, S. W. Barwick, S. Bash, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, J. Beise, C. Bellenghi, C. Benning, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Böttcher, J. Braun, B. Brinson, J. Brostean-Kaiser, L. Brusa, R. T. Burley, D. Butterfield, M. A. Campana, I. Caracas, K. Carloni, J. Carpio, S. Chattopadhyay, N. Chau, Z. Chen, D. Chirkin, S. Choi, B. A. Clark, A. Coleman, G. H. Collin, A. Connolly, J. M. Conrad, P. Coppin, R. Corley, P. Correa, et al. (360 additional authors not shown)Comments: 24 pages, 19 figures, 2 tables, submitted to JINSTSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)
More than 10,000 photomultiplier tubes (PMTs) with a diameter of 80 mm will be installed in multi-PMT Digital Optical Modules (mDOMs) of the IceCube Upgrade. These have been tested and pre-calibrated at two sites. A throughput of more than 1000 PMTs per week with both sites was achieved with a modular design of the testing facilities and highly automated testing procedures. The testing facilities can easily be adapted to other PMTs, such that they can, e.g., be re-used for testing the PMTs for IceCube-Gen2. Single photoelectron response, high voltage dependence, time resolution, prepulse, late pulse, afterpulse probabilities, and dark rates were measured for each PMT. We describe the design of the testing facilities, the testing procedures, and the results of the acceptance tests.
- [83] arXiv:2404.19592 (cross-list from quant-ph) [pdf, other]
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Title: Programmable activation of quantum emitters in high-purity silicon with focused carbon ion beamsAuthors: M. Hollenbach, N. Klingner, P. Mazarov, W. Pilz, A. Nadzeyka, F. Mayer, N. V. Abrosimov, L. Bischoff, G. Hlawacek, M. Helm, G. V. AstakhovComments: 7 pages, 5 figuresSubjects: Quantum Physics (quant-ph); Applied Physics (physics.app-ph)
Carbon implantation at the nanoscale is highly desired for the engineering of defect-based qubits in a variety of materials, including silicon, diamond, SiC and hBN. However, the lack of focused carbon ion beams does not allow for the full disclosure of their potential for application in quantum technologies. Here, we develop and use a carbon source for focused ion beams for the simultaneous creation of two types of quantum emitters in silicon, the W and G centers. Furthermore, we apply a multi-step implantation protocol for the programmable activation of the G centers with sub-100- nm resolution. This approach provides a route for significant enhancement of the creation yield of single G centers in carbon-free silicon wafers. Our experimental demonstration is an important step towards nanoscale engineering of telecom quantum emitters in silicon of high crystalline quality and isotope purity.
- [84] arXiv:2404.19605 (cross-list from cs.LG) [pdf, other]
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Title: Data-Driven Invertible Neural Surrogates of Atmospheric TransmissionComments: Manuscript accepted for presentation and publication at the 2024 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)Subjects: Machine Learning (cs.LG); Computer Vision and Pattern Recognition (cs.CV); Atmospheric and Oceanic Physics (physics.ao-ph)
We present a framework for inferring an atmospheric transmission profile from a spectral scene. This framework leverages a lightweight, physics-based simulator that is automatically tuned - by virtue of autodifferentiation and differentiable programming - to construct a surrogate atmospheric profile to model the observed data. We demonstrate utility of the methodology by (i) performing atmospheric correction, (ii) recasting spectral data between various modalities (e.g. radiance and reflectance at the surface and at the sensor), and (iii) inferring atmospheric transmission profiles, such as absorbing bands and their relative magnitudes.
- [85] arXiv:2404.19613 (cross-list from cond-mat.mtrl-sci) [pdf, ps, other]
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Title: High-throughput discovery of metal oxides with high thermoelectric performance via interpretable feature engineering on small dataSubjects: Materials Science (cond-mat.mtrl-sci); Applied Physics (physics.app-ph); Computational Physics (physics.comp-ph)
In this work, we have proposed a data-driven screening framework combining the interpretable machine learning with high-throughput calculations to identify a series of metal oxides that exhibit both high-temperature tolerance and high power factors. Aiming at the problem of weak generalization ability of small data with power factors at high temperatures, we employ symbolic regression for feature creation which enhances the robustness of the model while preserving the physical meaning of features. 33 candidate metal oxides are finally targeted for high-temperature thermoelectric applications from a pool of 48,694 compounds in the Materials Project database. The Boltzmann transport theory is utilized to perform electrical transport properties calculations at 1,000 K. The relaxation time is approximated by employing constant electron-phonon coupling based on the deformation potential theory. Considering band degeneracy, the electron group velocity is obtained using the momentum matrix element method, yielding 28 materials with power factors greater than 50 ${\mu}W cm^{-1} K^{-2} $. The high-throughput framework we proposed is instrumental in the selection of metal oxides for high-temperature thermoelectric applications. Furthermore, our data-driven analysis and transport calculation suggest that metal oxides rich in elements such as cerium (Ce), tin (Sn), and lead (Pb) tend to exhibit high power factors at high temperatures.
- [86] arXiv:2404.19624 (cross-list from hep-ph) [pdf, other]
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Title: Recent Neutrino Parameters Impact on the Effective Majorana Neutrino Mass in 0$νββ$ DecayComments: 6 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Data Analysis, Statistics and Probability (physics.data-an)
We investigate how recent updates to neutrino oscillation parameters and the sum of neutrino masses influence the sensitivity of neutrinoless double-beta (0$\nu\beta\beta$) decay experiments. Incorporating the latest cosmological constraints on the sum of neutrino masses and laboratory measurements on oscillations, we determine the sum of neutrino masses for both the normal hierarchy (NH) and the inverted hierarchy (IH). Our analysis reveals a narrow range for the sum of neutrino masses, approximately 0.06 eV/c$^2$ for NH and 0.102 eV/c$^2$ for IH. Utilizing these constraints, we calculate the effective Majorana masses for both NH and IH scenarios, establishing the corresponding allowed regions. Importantly, we find that the minimum neutrino mass is non-zero, as constrained by the current oscillation parameters. Additionally, we estimate the half-life of 0$\nu\beta\beta$ decay using these effective Majorana masses for both NH and IH. Our results suggest that upcoming ton-scale experiments will comprehensively explore the IH scenario, while 100-ton-scale experiments will effectively probe the parameter space for the NH scenario, provided the background index can achieve 1 event/kton-year in the region of interest.
- [87] arXiv:2404.19649 (cross-list from cs.LG) [pdf, other]
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Title: Landmark Alternating DiffusionSubjects: Machine Learning (cs.LG); Statistics Theory (math.ST); Data Analysis, Statistics and Probability (physics.data-an); Machine Learning (stat.ML)
Alternating Diffusion (AD) is a commonly applied diffusion-based sensor fusion algorithm. While it has been successfully applied to various problems, its computational burden remains a limitation. Inspired by the landmark diffusion idea considered in the Robust and Scalable Embedding via Landmark Diffusion (ROSELAND), we propose a variation of AD, called Landmark AD (LAD), which captures the essence of AD while offering superior computational efficiency. We provide a series of theoretical analyses of LAD under the manifold setup and apply it to the automatic sleep stage annotation problem with two electroencephalogram channels to demonstrate its application.
- [88] arXiv:2404.19653 (cross-list from cond-mat.stat-mech) [pdf, other]
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Title: BAD-NEUS: Rapidly converging trajectory stratificationComments: 18 pages, 10 figuresSubjects: Statistical Mechanics (cond-mat.stat-mech); Computational Physics (physics.comp-ph)
An issue for molecular dynamics simulations is that events of interest often involve timescales that are much longer than the simulation time step, which is set by the fastest timescales of the model. Because of this timescale separation, direct simulation of many events is prohibitively computationally costly. This issue can be overcome by aggregating information from many relatively short simulations that sample segments of trajectories involving events of interest. This is the strategy of Markov state models (MSMs) and related approaches, but such methods suffer from approximation error because the variables defining the states generally do not capture the dynamics fully. By contrast, once converged, the weighted ensemble (WE) method aggregates information from trajectory segments so as to yield unbiased estimates of both thermodynamic and kinetic statistics. Unfortunately, errors decay no faster than unbiased simulation in WE. Here we introduce a theoretical framework for describing WE that shows that introduction of an element of stratification, as in nonequilibrium umbrella sampling (NEUS), accelerates convergence. Then, building on ideas from MSMs and related methods, we propose an improved stratification that allows approximation error to be reduced systematically. We show that the improved stratification can decrease simulation times required to achieve a desired precision by orders of magnitude.
- [89] arXiv:2404.19660 (cross-list from cs.LG) [pdf, other]
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Title: Decoder Decomposition for the Analysis of the Latent Space of Nonlinear Autoencoders With Wind-Tunnel Experimental DataSubjects: Machine Learning (cs.LG); Fluid Dynamics (physics.flu-dyn)
Turbulent flows are chaotic and multi-scale dynamical systems, which have large numbers of degrees of freedom. Turbulent flows, however, can be modelled with a smaller number of degrees of freedom when using the appropriate coordinate system, which is the goal of dimensionality reduction via nonlinear autoencoders. Autoencoders are expressive tools, but they are difficult to interpret. The goal of this paper is to propose a method to aid the interpretability of autoencoders. This is the decoder decomposition. First, we propose the decoder decomposition, which is a post-processing method to connect the latent variables to the coherent structures of flows. Second, we apply the decoder decomposition to analyse the latent space of synthetic data of a two-dimensional unsteady wake past a cylinder. We find that the dimension of latent space has a significant impact on the interpretability of autoencoders. We identify the physical and spurious latent variables. Third, we apply the decoder decomposition to the latent space of wind-tunnel experimental data of a three-dimensional turbulent wake past a bluff body. We show that the reconstruction error is a function of both the latent space dimension and the decoder size, which are correlated. Finally, we apply the decoder decomposition to rank and select latent variables based on the coherent structures that they represent. This is useful to filter unwanted or spurious latent variables, or to pinpoint specific coherent structures of interest. The ability to rank and select latent variables will help users design and interpret nonlinear autoencoders.
- [90] arXiv:2404.19692 (cross-list from cond-mat.mtrl-sci) [pdf, ps, other]
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Title: The finite-$T$ Lorentz number and the thermal conductivity. Aluminum and carbon conductivities from ambient to millions of degrees KelvinAuthors: M. W. C. Dharma-wardana (NRC Canada)Comments: 5 pages, 5 figures and also supplementary material with six pages and two figuresSubjects: Materials Science (cond-mat.mtrl-sci); Plasma Physics (physics.plasm-ph)
Theoretical prediction of the thermal conductivity $\kappa$ of metal-like electron-ion systems would be greatly simplified if a convenient generalization of the Lorentz number $L_N$ for arbitrary temperatures ($T$) and densities were available. Such calculations are needed in astrophysics, high-energy-density physics, semiconductor physics as well as in materials science. We present a finite-$T$ form of $L_N(T)$, expressed in terms of elementary Fermi integrals. It is a universal function of $t=T/E_F$, where $E_F$ is the Fermi energy of the electrons. A convenient four-parameter fit to $L_N(t)$ for $t=0-\infty$ further simplifies the applications. The effect of electron-electron interactions is also briefly discussed. Calculations for $L_N(t)$ and thermal conductivities $\kappa$ for Al and C are presented at several compressions and into the million-Kelvin range. Experimental isobaric conductivities for Al just above the meting point, and isochoric conductivities for Al and C from available density-functional theory simulations and average-atom calculations are used as comparisons.
- [91] arXiv:2404.19743 (cross-list from cond-mat.mtrl-sci) [pdf, other]
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Title: Comparative Analysis of Fluctuations in Viscoelastic Stress: A Comparison of the Temporary Network and Dumbbell modelsComments: 11 pages, 12 figures, The following article has been submitted to The Journal of Chemical Physics. After it is published, it will be found at Link: this https URL&gclid=Cj0KCQjwir2xBhC_ARIsAMTXk85XWFzcccAjiPwwNGQTvsW5B-DrpAbdS5nJ0D75RtXKOqHGsfyNzpgaAqVhEALw_wcBSubjects: Materials Science (cond-mat.mtrl-sci); Statistical Mechanics (cond-mat.stat-mech); Fluid Dynamics (physics.flu-dyn)
Traditionally, stress fluctuations in flowing and deformed materials are overlooked, with an obvious focus on average stresses in a continuum mechanical approximation. However, these fluctuations, often dismissed as noise, hold the potential to provide direct insights into the material structure and its structure-stress coupling, uncovering detailed aspects of fluid transport and relaxation behaviors. Despite advancements in experimental techniques allowing for the visualization of these fluctuations, their significance remains largely untapped, as modeling efforts continue to target Newtonian fluids within the confines of Gaussian noise assumptions. In the present work a comparative analysis of stress fluctuations in two distinct microstructural models is carried out: the temporary network model and the dumbbell model. Despite both models conforming to the Upper Convected Maxwell Model at a macroscopic level, the temporary network model predicts non-Gaussian fluctuations. We find that stress fluctuations within the temporary network model exhibit more pronounced abruptness at local scale, with only an enlargement of the control volume leading to a gradual Gaussian-like noise, diminishing the differences between the two models. These findings underscore the heightened sensitivity of fluctuating rheology to microstructural details and the microstructure-flow coupling, beyond what is captured by macroscopically averaged stresses.
Replacements for Wed, 1 May 24
- [92] arXiv:2112.05098 (replaced) [pdf, other]
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Title: Intraspecific predator interference promotes biodiversity in ecosystemsComments: Main text 14 pages, 3 figures. Appendices 34 pages, 15 Appendix-figuresSubjects: Populations and Evolution (q-bio.PE); Statistical Mechanics (cond-mat.stat-mech); Biological Physics (physics.bio-ph)
- [93] arXiv:2203.01014 (replaced) [pdf, other]
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Title: Cumulative Merging Percolation: A long-range percolation process in networksComments: 12 pages, 6 figuresJournal-ref: Phys. Rev. E 105, 054310 (2022)Subjects: Statistical Mechanics (cond-mat.stat-mech); Social and Information Networks (cs.SI); Physics and Society (physics.soc-ph)
- [94] arXiv:2203.02886 (replaced) [pdf, other]
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Title: Strong DeterminismAuthors: Eddy Keming ChenComments: Accepted version, Philosophers' ImprintSubjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); History and Philosophy of Physics (physics.hist-ph)
- [95] arXiv:2212.14549 (replaced) [pdf, other]
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Title: Proper Orthogonal Descriptors for Multi-element Chemical SystemsAuthors: Ngoc-Cuong NguyenComments: 39 pages, 9 figures, 7 tables. arXiv admin note: text overlap with arXiv:2209.02362Subjects: Chemical Physics (physics.chem-ph); Materials Science (cond-mat.mtrl-sci)
- [96] arXiv:2301.02368 (replaced) [pdf, other]
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Title: Emergence of simple and complex contagion dynamics from weighted belief networksJournal-ref: Science Advances.10,eadh4439(2024)Subjects: Social and Information Networks (cs.SI); Physics and Society (physics.soc-ph)
- [97] arXiv:2303.07977 (replaced) [pdf, ps, other]
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Title: Direct generation of time-energy-entangled W triphotons in atomic vaporAuthors: Kangkang Li, Jianming Wen, Yin Cai, Saeid Vashahri Ghamsari, Changbiao Li, Feng Li, Zhaoyang Zhang, Yanpeng Zhang, Min XiaoComments: updated versionSubjects: Quantum Physics (quant-ph); Optics (physics.optics)
- [98] arXiv:2303.08668 (replaced) [pdf, other]
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Title: The transition to synchronization of networked systemsAuthors: Atiyeh Bayani, Fahimeh Nazarimehr, Sajad Jafari, Kirill Kovalenko, Gonzalo Contreras-Aso, Karin Alfaro-Bittner, Ruben J. Sánchez-García, Stefano BoccalettiComments: 24 pages, 9 figuresSubjects: Physics and Society (physics.soc-ph); Chaotic Dynamics (nlin.CD)
- [99] arXiv:2304.02587 (replaced) [pdf, other]
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Title: A Two-Phase Model of Early Atherosclerotic Plaque Development with LDL Toxicity EffectsSubjects: Tissues and Organs (q-bio.TO); Fluid Dynamics (physics.flu-dyn)
- [100] arXiv:2304.04664 (replaced) [pdf, other]
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Title: Inductive biases in deep learning models for weather predictionAuthors: Jannik Thuemmel (1), Matthias Karlbauer (1), Sebastian Otte (1), Christiane Zarfl (1), Georg Martius (2), Nicole Ludwig (1), Thomas Scholten (1), Ulrich Friedrich (3), Volker Wulfmeyer (4), Bedartha Goswami (1), Martin V. Butz (1) ((1) University of Tübingen, (2) Max Planck Institute for Intelligent Systems, (3) Deutscher Wetterdienst, (4) University of Hohenheim)Subjects: Atmospheric and Oceanic Physics (physics.ao-ph); Machine Learning (cs.LG)
- [101] arXiv:2306.15335 (replaced) [pdf, ps, other]
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Title: Space-Time Entropy, Space of Singularities and Gravity Origin: A Case StudyAuthors: Faycal Ben AddaComments: 26 Pages, 9 FiguresJournal-ref: International Journal of Geometric Methods in Modern Physics, 2450189 (30 pages). (2024)Subjects: General Physics (physics.gen-ph)
- [102] arXiv:2309.07949 (replaced) [pdf, other]
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Title: Compositional metrics of fast and slow Alfvenic solar wind emerging from coronal holes and their boundariesAuthors: Tamar Ervin, Stuart D. Bale, Samuel T. Badman, Yeimy J. Rivera, Orlando Romeo, Jia Huang, Pete Riley, Trevor A. Bowen, Susan T. Lepri, Ryan M. DeweyComments: 23 pages, 10 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)
- [103] arXiv:2309.08711 (replaced) [pdf, other]
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Title: A fast-running physics-based wake model for a semi-infinite wind farmAuthors: Majid Bastankhah, Mohammad Mehdi Mohammadi, Charlie Lees, Gonzalo Pablo Navarro Diaz, Oliver Buxton, Stefan IvanellJournal-ref: J. Fluid Mech. 985 (2024) A43Subjects: Fluid Dynamics (physics.flu-dyn)
- [104] arXiv:2310.11543 (replaced) [pdf, other]
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Title: A variational data assimilation approach for sparse velocity reference data in coarse RANS simulations through a corrective forcing termSubjects: Fluid Dynamics (physics.flu-dyn)
- [105] arXiv:2311.08899 (replaced) [pdf, other]
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Title: Self-Organized Time Crystal in Driven-Dissipative Quantum SystemComments: 6 pages, 4 figuresSubjects: Quantum Physics (quant-ph); Adaptation and Self-Organizing Systems (nlin.AO); Atomic Physics (physics.atom-ph)
- [106] arXiv:2311.10292 (replaced) [pdf, other]
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Title: Realization of a programmable multi-purpose photonic quantum memory with over-thousand qubit manipulationsComments: 17 pages, 19 figuresJournal-ref: Phys. Rev. X 14, 021018 (2024)Subjects: Quantum Physics (quant-ph); Emerging Technologies (cs.ET); Optics (physics.optics)
- [107] arXiv:2311.15757 (replaced) [pdf, ps, other]
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Title: Self-diffusion in a strongly coupled non-neutral plasmaComments: 11 pages, 7 figuresJournal-ref: Phys. Rev. A 109, 043116 (2024)Subjects: Atomic Physics (physics.atom-ph)
- [108] arXiv:2312.03273 (replaced) [pdf, other]
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Title: Perfectly matched layers for the Boltzmann equation: stability and sensitivity analysisComments: 29 pages, 3 figures, 12 tablesSubjects: Numerical Analysis (math.NA); Computational Physics (physics.comp-ph)
- [109] arXiv:2312.07027 (replaced) [pdf, ps, other]
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Title: Effect of shear flow on the transverse thermal conductivity of polymer meltsComments: 29 pages, 13 figuresSubjects: Soft Condensed Matter (cond-mat.soft); Computational Physics (physics.comp-ph)
- [110] arXiv:2312.12996 (replaced) [pdf, other]
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Title: A mesh-free framework for high-order simulations of viscoelastic flows in complex geometriesComments: submitted to JNNFM KW special issue, Dec 2023 revision submitted April 2024Subjects: Fluid Dynamics (physics.flu-dyn)
- [111] arXiv:2401.00858 (replaced) [pdf, other]
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Title: RCS reduction method with anomalous reflection metasurfaces using Floquet analysis : design modelling and measurementAuthors: Matthieu Elineau, Renaud Loison, Stéphane Méric, Raphaël Gillard, Pascal Pagani, Geneviève Mazé-Merceur, Philippe PouliguenSubjects: Applied Physics (physics.app-ph); Signal Processing (eess.SP); Optics (physics.optics)
- [112] arXiv:2401.10374 (replaced) [pdf, ps, other]
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Title: Printed Circuit Board Based Rotating Coils for Measuring Sextupole MagnetsAuthors: J. DiMarco (1) ((1) Fermilab)Comments: 28th International Conference on Magnet Technology (MT-28)Journal-ref: IEEE Trans.Appl.Supercond. 34 (2024) 5, 9000604Subjects: Accelerator Physics (physics.acc-ph)
- [113] arXiv:2401.14041 (replaced) [pdf, other]
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Title: Quasi-single-stage optimization for permanent magnet stellaratorsComments: 21 pages, 17 figuresSubjects: Plasma Physics (physics.plasm-ph)
- [114] arXiv:2401.14075 (replaced) [pdf, other]
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Title: Generation of High-Brilliance Polarized $γ$-Rays via Vacuum Dichroism-assisted Vacuum BirefringenceAuthors: Chong Lv, Feng Wan, Yousef I. Salamin, Qian Zhao, Mamutjan Ababekri, Ruirui Xu, Jian-Xing LiSubjects: Plasma Physics (physics.plasm-ph)
- [115] arXiv:2401.15402 (replaced) [pdf, other]
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Title: Universality for Three Bosons with Large, Negative Effective Range: Aspects and AddendaAuthors: Harald W. Griesshammer (George Washington U.)Comments: 10 pages LaTeX2e (pdflatex) including 6 figures as 7 .pdf files using includegraphics and sn-jnl class. Contribution to the Proceedings of the 25th European Conference of Few-Body Physics, Mainz, 30 July - 4 August 2023. Typographical updates onlySubjects: Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Atomic and Molecular Clusters (physics.atm-clus); Atomic Physics (physics.atom-ph); Quantum Physics (quant-ph)
- [116] arXiv:2402.05067 (replaced) [pdf, other]
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Title: A Novel Paradigm in Solving Multiscale ProblemsSubjects: Fluid Dynamics (physics.flu-dyn); Machine Learning (cs.LG); Computational Physics (physics.comp-ph)
- [117] arXiv:2402.08366 (replaced) [pdf, other]
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Title: Small-scale dynamo with nonzero correlation timeComments: 20 pages, 3 figures, 1 table. Version incorporating referees' comments. Major changes: in section 3.3, pointed out an oversight in a previous work that explains some qualitative differences in the final evolution equation; discussed the validity of WKB; fixed a mistake in section 4.2.5 (that does not affect the final results); clarified the use of equation 13 based on a comment receivedSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)
- [118] arXiv:2402.09037 (replaced) [pdf, other]
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Title: Metasurface of strongly coupled excitons and nanoplasmonic arraysAuthors: Farsane Tabataba-Vakili, Lukas Krelle, Lukas Husel, Huy P. G. Nguyen, Zhijie Li, Ismail Bilgin, Kenji Watanabe, Takashi Taniguchi, Alexander HögeleComments: 8 pages, 3 figuresSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Materials Science (cond-mat.mtrl-sci)
- [119] arXiv:2402.10075 (replaced) [pdf, other]
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Title: Direct laser cooling of Rydberg atoms with an isolated-core transitionComments: 6 pages, 3 figuresSubjects: Atomic Physics (physics.atom-ph)
- [120] arXiv:2402.10692 (replaced) [pdf, other]
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Title: Understanding inner-shell excitations in molecules through spectroscopy of the 4f hole states of YbFComments: 14 pages, 10 figures. Improved introduction; improved discussion of repumping schemes for laser cooling and potential applications of the 4f hole statesSubjects: Atomic Physics (physics.atom-ph); Chemical Physics (physics.chem-ph)
- [121] arXiv:2402.10741 (replaced) [pdf, other]
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Title: Identifying heterogeneous micromechanical properties of biological tissues via physics-informed neural networksSubjects: Numerical Analysis (math.NA); Biological Physics (physics.bio-ph)
- [122] arXiv:2402.12365 (replaced) [pdf, other]
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Title: Universal Physics Transformers: A Framework For Efficiently Scaling Neural OperatorsAuthors: Benedikt Alkin, Andreas Fürst, Simon Schmid, Lukas Gruber, Markus Holzleitner, Johannes BrandstetterSubjects: Machine Learning (cs.LG); Artificial Intelligence (cs.AI); Fluid Dynamics (physics.flu-dyn)
- [123] arXiv:2402.13947 (replaced) [pdf, other]
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Title: Circular dichroism in perturbative harmonic generation in achiral nanostructures under vortex beam irradiationComments: 52 pages, 4 figuresSubjects: Optics (physics.optics)
- [124] arXiv:2402.14089 (replaced) [pdf, other]
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Title: The Origin of the Slow-to-Alfvén Wave Cascade Power Ratio and its Implications for Particle Heating in Accretion FlowsComments: Accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
- [125] arXiv:2402.14628 (replaced) [pdf, other]
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Title: Tunable transport in bi-disperse porous materials with vascular structureComments: 18 pages, 11 figures, revision for Phys. Rev. FluidsSubjects: Soft Condensed Matter (cond-mat.soft); Materials Science (cond-mat.mtrl-sci); Fluid Dynamics (physics.flu-dyn)
- [126] arXiv:2403.03239 (replaced) [pdf, ps, other]
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Title: Note: Harnessing Tellurium Nanoparticles in the Digital Realm Plasmon Resonance, in the Context of Brewster's Angle and the Drude Model for Fake News Adsorption in Incomplete Information GamesAuthors: Yasuko KawahataComments: Tellurium Nanoparticles, Snell's Law, Soliton Solution, Anamorphic Surfaces, Nonlinear Dynamics, Fake News Adsorption, User Behavior Modeling, Health Improvement Strategies, Plasmonic Sensors This paper is partially an attempt to utilize "Generative AI" and was written with educational intent. There are currently no plans for it to become a peer-reviewed paperSubjects: Physics and Society (physics.soc-ph); Artificial Intelligence (cs.AI)
- [127] arXiv:2403.05405 (replaced) [pdf, other]
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Title: Experimental set-up for thermal measurements at the nanoscale using an SThM probe with niobium nitride thermometerAuthors: R. Swami, G. Julie, S. Le-Denmat, G. Pernot, D. Singhal, J. Paterson, J. Maire, J.F. Motte, N. Paillet, H. Guillou, S. Gomes, O. BourgeoisComments: 17 pages, 13 figuresSubjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Applied Physics (physics.app-ph)
- [128] arXiv:2403.05585 (replaced) [pdf, ps, other]
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Title: Plasmon Resonance Model: Investigation of Analysis of Fake News Diffusion Model with Third Mover Intervention Using Soliton Solution in Non-Complete Information Game under Repeated Dilemma ConditionAuthors: Yasuko KawahataComments: Plasmon Resonance Model, Soliton Solution, Third Mover,Fake News, Non-Complete Information Game, Nonlinear Partial Differential Equations, First Mover, Second Mover, Third Mover, Diffusion Dynamics, Iteration DilemmaSubjects: Physics and Society (physics.soc-ph); Artificial Intelligence (cs.AI)
- [129] arXiv:2403.05593 (replaced) [pdf, ps, other]
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Title: Introducing First-Principles Calculations: New Approach to Group Dynamics and Bridging Social Phenomena in TeNP-Chain Based Social Dynamics SimulationsAuthors: Yasuko KawahataComments: TeNP Chains, First-principles calculations, Tellurium nanoparticles (TeNPs), Graphene, Fake news dissemination, Social cohesion, Information Flow Disruption, Quantum Mechanics, Interdisciplinary approach, Misinformation mitigationSubjects: Physics and Society (physics.soc-ph); Artificial Intelligence (cs.AI); Physics Education (physics.ed-ph)
- [130] arXiv:2403.06405 (replaced) [pdf, other]
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Title: Chemical Potentials and the One-Electron Hamiltonian of the Second-Order Perturbation Theory from the Functional Derivative ApproachSubjects: Chemical Physics (physics.chem-ph)
- [131] arXiv:2403.08127 (replaced) [pdf, ps, other]
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Title: Guidelines for the Creation of Analysis Ready DataAuthors: Harriette Phillips, Aiden Price, Owen Forbes, Claire Boulange, Kerrie Mengersen, Marketa Reeves, Rebecca GlauertComments: 49 pages, 3 figures, 3 tables, and 5 appendicesSubjects: Databases (cs.DB); Data Analysis, Statistics and Probability (physics.data-an); Other Statistics (stat.OT)
- [132] arXiv:2403.16389 (replaced) [pdf, other]
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Title: Illuminating Systematic Trends in Nuclear Data with Generative Machine Learning ModelsComments: New version uploaded after rewriting several sections for clarity and one new figure addedSubjects: Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
- [133] arXiv:2403.18473 (replaced) [pdf, ps, other]
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Title: DMRG-tailored coupled cluster method in the 4c-relativistic domain: General implementation and application to the NUHFI and NUF$_3$ moleculesAuthors: Jakub Višňák (1, 2, 3), Jan Brandejs (1, 2, 4), Mihály Máté (5, 6), Lucas Visscher (7), Örs Legeza (5, 8), Jiří Pittner (1) ((1) J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Prague, (2) Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic, (3) Middle East Technical University, Ankara, Türkiye, (4) Faculty of Science, Humanities and Education, Technical University of Liberec, Czech Republic, (5) Strongly Correlated Systems "Lendület'' Research Group, Wigner Research Centre for Physics, Budapest, Hungary, (6) Department of Mathematics, Technical University of Munich, Germany, (7) Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, Netherlands)Comments: 12 pages, 9 figuresSubjects: Chemical Physics (physics.chem-ph)
- [134] arXiv:2404.04263 (replaced) [pdf, ps, other]
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Title: An Exact Invariant for Relativistic Linear Harmonic Oscillator with Time-dependent FrequencySubjects: Classical Physics (physics.class-ph)
- [135] arXiv:2404.06522 (replaced) [pdf, other]
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Title: (Pseudo-)Synthetic BRST quantisation of the bosonic string and the higher quantum origin of dualitiesAuthors: Andrei T. PatrascuSubjects: General Physics (physics.gen-ph)
- [136] arXiv:2404.08423 (replaced) [pdf, other]
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Title: SIR-RL: Reinforcement Learning for Optimized Policy Control during Epidemiological Outbreaks in Emerging Market and Developing EconomiesComments: 27 pages, 12 figuresSubjects: Machine Learning (cs.LG); Physics and Society (physics.soc-ph); Populations and Evolution (q-bio.PE)
- [137] arXiv:2404.10007 (replaced) [pdf, other]
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Title: Is a direct numerical simulation (DNS) of Navier-Stokes equations with small enough grid spacing and time-step definitely reliable/correct?Comments: 27 pages, 18 figuresSubjects: Fluid Dynamics (physics.flu-dyn)
- [138] arXiv:2404.11403 (replaced) [pdf, other]
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Title: Six decades of the FitzHugh-Nagumo model: A guide through its spatio-temporal dynamics and influence across disciplinesComments: 38 pages, 18 figuresSubjects: Pattern Formation and Solitons (nlin.PS); Mathematical Physics (math-ph); Biological Physics (physics.bio-ph); Computational Physics (physics.comp-ph); Other Quantitative Biology (q-bio.OT)
- [139] arXiv:2404.11777 (replaced) [pdf, other]
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Title: Direct measurement of energy transfer in strongly driven rotating turbulenceSubjects: Fluid Dynamics (physics.flu-dyn)
- [140] arXiv:2404.15102 (replaced) [pdf, other]
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Title: Omnidirectional gradient force optical trapping in dielectric nanocavities by inverse designAuthors: Beñat Martinez de Aguirre Jokisch, Benjamin Falkenberg Gøtzsche, Philip Trøst Kristensen, Martijn Wubs, Ole Sigmund, Rasmus Ellebæk ChristiansenSubjects: Optics (physics.optics)
- [141] arXiv:2404.15926 (replaced) [pdf, other]
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Title: Microwave Technologies in Experiments for Detection of Dark Matter AxionsSubjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex)
- [142] arXiv:2404.16993 (replaced) [pdf, ps, other]
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Title: Optimizing Spectral Phase Transfer in Four-Wave Mixing with Gas-filled Capillaries: A Trade-off StudyAuthors: Hao Zhang, Linshan Sun, Jack Hirschman, Mirali Seyed Shariatdoust, Federico Belli, Sergio CarbajoComments: Submitted to Optics ExpressSubjects: Optics (physics.optics)
- [143] arXiv:2404.17879 (replaced) [pdf, other]
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Title: Trapping polar molecules by surface acoustic wavesSubjects: Quantum Physics (quant-ph); Atomic and Molecular Clusters (physics.atm-clus)
- [144] arXiv:2404.18913 (replaced) [pdf, ps, other]
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Title: Two-axis twisting using Floquet-engineered XYZ spin models with polar moleculesAuthors: Calder Miller, Annette N. Carroll, Junyu Lin, Henrik Hirzler, Haoyang Gao, Hengyun Zhou, Mikhail D. Lukin, Jun YeComments: 20 pages, 4 figures + 4 extended data figuresSubjects: Quantum Gases (cond-mat.quant-gas); Atomic Physics (physics.atom-ph)
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