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Condensed Matter > Strongly Correlated Electrons
Title: Variational Improvement of the Hartree-Fock Approach to the 2D Hubbard Model
(Submitted on 7 Apr 2024 (v1), last revised 10 Apr 2024 (this version, v2))
Abstract: We consider a refinement of the usual Hartree-Fock method applied the 2D Hubbard model, in Nambu spinor formulation. The new element is the addition of a ''condensate inducing'' term proportional to a variational parameter h to the Hartree-Fock Hamiltonian, which generates an s- or d-wave condensate. This modified Hartree-Fock Hamiltonian is used only to generate variational trial states; energy expectation values are computed in the full two-dimensional Hubbard Hamiltonian with no modification. It is found that there exist trial states with non-vanishing condensates that are significantly lower in energy than the standard Hartree-Fock ground states, in some range of the U/t-density plane.
Submission history
From: Kazue Matsuyama [view email][v1] Sun, 7 Apr 2024 01:38:48 GMT (59kb)
[v2] Wed, 10 Apr 2024 01:47:55 GMT (59kb)
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