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Main Authors: Yabuuchi, Yoshihiro, Danshita, Ippei
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2511.14260
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author Yabuuchi, Yoshihiro
Danshita, Ippei
author_facet Yabuuchi, Yoshihiro
Danshita, Ippei
contents We investigate the stability of current-carrying states with quasi-momentum $K$ in the Bose-condensed phase of the hard-core Bose-Hubbard model on a square lattice, where particles transfer between two sites separated by distance $r$ with hopping amplitude decaying algebraically with $r$ as $\propto r^{-α}$. Using a mean-field theory, we analyze the excitation spectrum and determine the critical quasi-momenta associated with Landau and dynamical instabilities. We find that the long-range hopping suppresses the critical quasi-momenta and makes them vanish at $α=3$. Near $α=3$, we show that the critical quasi-momentum $K_{\mathrm{c}}$ for the dynamical instability exhibits the scaling behavior $K_\mathrm{c} \propto Δ^{1+Δ}$ with $Δ=α-3$, where the scaling exponent explicitly depends on $Δ$, as a consequence of the long-range nature of the hopping.
format Preprint
id arxiv_https___arxiv_org_abs_2511_14260
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Stability of current-carrying states in hard-core bosons with long-range hopping on a square lattice
Yabuuchi, Yoshihiro
Danshita, Ippei
Quantum Gases
We investigate the stability of current-carrying states with quasi-momentum $K$ in the Bose-condensed phase of the hard-core Bose-Hubbard model on a square lattice, where particles transfer between two sites separated by distance $r$ with hopping amplitude decaying algebraically with $r$ as $\propto r^{-α}$. Using a mean-field theory, we analyze the excitation spectrum and determine the critical quasi-momenta associated with Landau and dynamical instabilities. We find that the long-range hopping suppresses the critical quasi-momenta and makes them vanish at $α=3$. Near $α=3$, we show that the critical quasi-momentum $K_{\mathrm{c}}$ for the dynamical instability exhibits the scaling behavior $K_\mathrm{c} \propto Δ^{1+Δ}$ with $Δ=α-3$, where the scaling exponent explicitly depends on $Δ$, as a consequence of the long-range nature of the hopping.
title Stability of current-carrying states in hard-core bosons with long-range hopping on a square lattice
topic Quantum Gases
url https://arxiv.org/abs/2511.14260