Year: 2025
Type: preprint
Abstract: We study an attractive Hubbard model on bipartite lattices. In the grand canonical formalism,we prove the existence of superconducting long-range order in the ground state on Lieb lattices with the chemical potential corresponding to half filling. We also study the low-energy excitations above several ground states for the translationally invariant Hamiltonian. We prove the following: (i) The pairing excitations are gapless above the ground states when the number of fermions deviates from that of the half filling by the order of the volume. (ii) A certain class of single-fermion excitations shows a non-vanishing spectral gap above the ground state with an even number of fermions in a strong coupling and low-density regime.
Source: arXiv (Cornell University)
Authors: Goto, Yukimi, Koma, Tohru, Yoshida, Hironobu
Institutions: The University of Tokyo, RIKEN, Gakushuin University
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2493344581, 格子QCD模型の数学解析, G7045930133
OpenAlex ID: W7083511116
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