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Statistical Mechanics

New submissions

[ total of 19 entries: 1-19 ]
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New submissions for Wed, 22 Mar 23

[1]  arXiv:2303.11870 [pdf, other]
Title: The impact of decoherence on the route to equilibrium
Comments: 13 pages, 6 figures
Subjects: Statistical Mechanics (cond-mat.stat-mech); Quantum Physics (quant-ph)

We study the time evolution of a single qubit when coupling to a bath, within the framework of projection operator method. Employing the so-called modified Redfield theory which also treats the energy conserving interaction non-perturbatively, we are able to study the regime beyond the scope of the usual approach. The reduced equations of motion for the qubit are derived in a idealistic system where both the bath and the interactions are modeled by Gaussian distributed random matrices. In strong decoherence regime, a simple relation between the bath correlation function and decoherence process induced by energy conserving interaction is found. It implies that energy conserving interaction slows down the relaxation process, which leads to a zeno freezing if it is sufficiently strong.Furthermore, our results are also confirmed in numerical simulations.

[2]  arXiv:2303.11988 [pdf, ps, other]
Title: One-component fermion plasma on a sphere at finite temperature. The anisotropy in the paths conformations
Authors: Riccardo Fantoni
Comments: 12 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:1806.02153
Subjects: Statistical Mechanics (cond-mat.stat-mech); Computational Physics (physics.comp-ph)

In our previous work [R. Fantoni, Int. J. Mod. Phys. C, {\bf 29}, 1850064 (2018)] we studied, through a computer experiment, a one-component fermion plasma on a sphere at finite, non-zero, temperature. We extracted thermodynamic properties like the kinetic and internal energy per particle and structural properties like the radial distribution function, and produced some snapshots of the paths to study their shapes. Here we revisit such a study giving some more theoretical details explaining the paths shape anisotropic conformation due to the inhomogeneity in the polar angle of the variance of the random walk diffusion from the kinetic action.

Cross-lists for Wed, 22 Mar 23

[3]  arXiv:2303.11565 (cross-list from physics.optics) [pdf, other]
Title: Wavelength-division multiplexing optical Ising simulator enabling fully programmable spin couplings and external magnetic fields
Comments: 6 pages, 4 figures
Subjects: Optics (physics.optics); Statistical Mechanics (cond-mat.stat-mech); Emerging Technologies (cs.ET); Applied Physics (physics.app-ph)

Recently, spatial photonic Ising machines (SPIMs) have demonstrated the abilities to compute the Ising Hamiltonian of large-scale spin systems, with the advantages of ultrafast speed and high power efficiency. However, such optical computations have been limited to specific Ising models with fully connected couplings. Here we develop a wavelength-division multiplexing SPIM to enable programmable spin couplings and external magnetic fields as well for general Ising models. We experimentally demonstrate such a wavelength-division multiplexing SPIM with a single spatial light modulator, where the gauge transformation is implemented to eliminate the impact of pixel alignment. To show the programmable capability of general spin coupling interactions, we explore three spin systems: $\pm J$ models, Sherrington-Kirkpatrick models, and only locally connected ${{J}_{1}}\texttt{-}{{J}_{2}}$ models and observe the phase transitions between the spin-glass, ferromagnetic and paramagnetic phases. These results show that the wavelength-division multiplexing approach has great programmable flexibility of spin couplings and external magnetic fields, which provides the opportunities to solve general combinatorial optimization problems with large-scale and on-demand SPIM.

[4]  arXiv:2303.11947 (cross-list from cond-mat.quant-gas) [pdf, ps, other]
Title: The condensation of ideal Bose gas in a gravitational field in the framework of Dunkl-statistic
Comments: 10 pages 4 figures
Subjects: Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech); Quantum Physics (quant-ph)

In the framework of the theory of Dunkl-deformed bosons, Bose-Einstein condensation of two and three-dimensional Dunkl-boson gases confined in the one-dimensional gravitational field is investigated. Using the semi-classical approximation method, we calculate the expressions of the Dunkl-critical temperature $T_{c}^{D}$, the ground state population $\frac{N_{0}^{D}}{N}$ and the Dunkl-mean energy and Dunkl-specific heat functions. Further numerical calculation shows that the condensation temperature ratio $\frac{T_{c}^{D}}{T_{c}^{B}}$ increases with the increasing Wigner parameter.

[5]  arXiv:2303.12008 (cross-list from math-ph) [pdf, other]
Title: Monotonicity of the Scalar Curvature of the Quantum Exponential Family for Transverse-Field Ising Chains
Authors: Takemi Nakamura
Comments: 8 pages, 4 figures
Subjects: Mathematical Physics (math-ph); Statistical Mechanics (cond-mat.stat-mech)

The monotonicity of the scalar curvature of the state space equipped with the Bogoliubov-Kubo-Mori metric under more mixing a state is an important conjecture called the Petz conjecture. From the standpoint of quantum statistical mechanics, the quantum exponential family, a special submanifold of the state space, is central rather than the full state space. In this contribution, we investigate the monotonicity of the scalar curvature of the submanifold with respect to temperature for transverse-field Ising chains in various sizes and find that the monotonicity breaks down for the chains in finite sizes, whereas the monotonicity seems to hold if the chain is non-interacting or infinite-size. Our results suggest that finite-size effects can appear in the curvature through monotonicity with respect to majorization.

[6]  arXiv:2303.12009 (cross-list from physics.ao-ph) [pdf, other]
Title: Hasselmann's Program and Beyond: New Theoretical Tools for Understanding the Climate Crisis
Comments: 16 pages, 5 figures
Subjects: Atmospheric and Oceanic Physics (physics.ao-ph); Statistical Mechanics (cond-mat.stat-mech); Chaotic Dynamics (nlin.CD); Geophysics (physics.geo-ph); Physics and Society (physics.soc-ph)

Klaus Hasselmann's revolutionary intuition was to take advantage of the stochasticity associated with fast weather processes to probe the slow dynamics of the climate system. This has led to fundamentally new ways to study the response of climate models to perturbations, and to perform detection and attribution for climate change signals. Hasselmann's program has been extremely influential in climate science and beyond. We first summarise the main aspects of such a program using modern concepts and tools of statistical physics and applied mathematics. We then provide an overview of some promising scientific perspectives that might better clarify the science behind the climate crisis and that stem from Hasselmann's ideas. We show how to perform rigorous model reduction by constructing parametrizations in systems that do not necessarily feature a time-scale separation between unresolved and resolved processes. We propose a general framework for explaining the relationship between climate variability and climate change, and for performing climate change projections. This leads us seamlessly to explain some key general aspects of climatic tipping points. Finally, we show that response theory provides a solid framework supporting optimal fingerprinting methods for detection and attribution.

[7]  arXiv:2303.12028 (cross-list from hep-th) [pdf, other]
Title: Scalar CFTs from structural phase transitions
Authors: Junchen Rong
Comments: 35 pages, 16 figures
Subjects: High Energy Physics - Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech)

We discuss scalar conformal field theories (CFTs) that can be realized in structural phase transitions. The Landau condition and Lifshitz condition are reviewed, which are necessary conditions for a structural phase transition to be second order. We also review the perturbative analysis in $4-\epsilon$ expansion of the corresponding Landau actions, which were already analyzed thoroughly in the 80s. By identifying the global symmetries of these fixed points, it turns out that in perturbation theory only 6 different CFTs can be realized by commensurate structural phase transitions. This is a lecture note based on a series of talks given by the author. The goal of the lecture note is to bridge the gap between condensed matter physicists and conformal field theorists. The note will be further updated in the future.

Replacements for Wed, 22 Mar 23

[8]  arXiv:2207.04142 (replaced) [pdf, other]
Title: Cluster Scaling and Critical Points: A Cautionary Tale
Subjects: Statistical Mechanics (cond-mat.stat-mech)
[9]  arXiv:2210.15268 (replaced) [pdf, other]
Title: Calculation of critical exponents on fractal lattice Ising model by higher-order tensor renormalization group method
Authors: Jozef Genzor
Comments: 12 pages, 12 figures
Journal-ref: Phys. Rev. E 107, 034131 (2023)
Subjects: Statistical Mechanics (cond-mat.stat-mech)
[10]  arXiv:2302.04029 (replaced) [pdf, other]
Title: Geometrical optics of first-passage functionals of random acceleration
Authors: Baruch Meerson
Comments: 6 pages, 3 figures
Subjects: Statistical Mechanics (cond-mat.stat-mech); Probability (math.PR)
[11]  arXiv:2302.12762 (replaced) [pdf, other]
Title: Random sparse generators of Markovian evolution and their spectral properties
Comments: 20 pages, 7 figures
Subjects: Statistical Mechanics (cond-mat.stat-mech); Mathematical Physics (math-ph)
[12]  arXiv:2302.13666 (replaced) [pdf, ps, other]
Title: Correlated Noise and Critical Dimensions
Authors: Harukuni Ikeda
Comments: 7 pages
Subjects: Statistical Mechanics (cond-mat.stat-mech); Disordered Systems and Neural Networks (cond-mat.dis-nn)
[13]  arXiv:2303.10168 (replaced) [pdf, other]
Title: Inequality of avalanche sizes in models of fracture
Subjects: Statistical Mechanics (cond-mat.stat-mech); Disordered Systems and Neural Networks (cond-mat.dis-nn)
[14]  arXiv:2205.00803 (replaced) [pdf, other]
Title: Metastable states in the J1-J2 Ising model
Comments: 10 pages, 5 figures; corresponds to the published version
Journal-ref: Phys. Rev. E 107 (2023) 034124
Subjects: Materials Science (cond-mat.mtrl-sci); Statistical Mechanics (cond-mat.stat-mech)
[15]  arXiv:2206.14277 (replaced) [pdf, other]
Title: Integrable Floquet systems related to logarithmic conformal field theory
Comments: 22 pages, 2 figures
Subjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph); Exactly Solvable and Integrable Systems (nlin.SI)
[16]  arXiv:2209.11732 (replaced) [pdf, other]
Title: Replica approach to the generalized Rosenzweig-Porter model
Comments: Submission to SciPost; 48 pages, 7 figures; accepted version
Subjects: Disordered Systems and Neural Networks (cond-mat.dis-nn); Statistical Mechanics (cond-mat.stat-mech)
[17]  arXiv:2212.08824 (replaced) [pdf, other]
Title: Multi-point correlation functions in the boundary XXZ chain at finite temperature
Comments: 32 pages, V2 references added
Subjects: Exactly Solvable and Integrable Systems (nlin.SI); Statistical Mechanics (cond-mat.stat-mech); Mathematical Physics (math-ph)
[18]  arXiv:2212.12253 (replaced) [pdf, other]
Title: Finite temperature ferromagnetic transition in coherently coupled Bose gases
Comments: 10 pages, 5 figures
Subjects: Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech)
[19]  arXiv:2303.08341 (replaced) [pdf, ps, other]
Title: The singularities of the rate function of quantum coherent work in one-dimensional transverse field Ising model
Comments: 8 pages, 4 figures, welcome the comments. arXiv admin note: text overlap with arXiv:1810.04614, arXiv:cond-mat/0701768 by other authors
Subjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech)
[ total of 19 entries: 1-19 ]
[ showing up to 2000 entries per page: fewer | more ]

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