Superfluid density, Josephson relation and pairing fluctuations in a multi-component fermion superfluid

Zhang, Yi-Cai

doi:10.48550/arxiv.2012.11217

Cited by 1 publication

(1 citation statement)

References 38 publications

(58 reference statements)

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“…When q is small (q → 0), the matrix elements of two-particle Green functions of zero frequency ω = 0 are proportional to product of two order parameters, namely 47 G II,i j (q, 0)…”

Section: Two-particle Spectral Functionsmentioning

confidence: 99%

Superfluid density and collective modes of fermion superfluid in dice lattice

Wu,

Zhang,

Liu

et al. 2022

Preprint

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The superfluid properties of attractive Hubbard model in dice lattice are investigated. It is found that three superfluid order parameters increase as the interaction increases. When the filling factor falls into the flat band, due to the infinite large density of states, the resultant superfluid order parameters are proportional to interaction strength, which is in striking contrast with the exponentially small counterparts in usual superfluid (or superconductor). When the interaction is weak, and the filling factor is near the bottom of the lowest band (or the top of highest band), the superfluid density is determined by the effective mass of the lowest (or highest) single-particle band. When the interaction is strong and filling factor is small, the superfluid density is inversely proportional to interaction strength, which is related to effective mass of tightly bound pairs. In the strong interaction limit and finite filling, the asymptotic behaviors of superfluid density can be captured by a parabolic function of filling factor. Furthermore, when the filling is in flat band, the superfluid density shows a logarithmic singularity as the interaction approaches zero. In addition, there exist three undamped collective modes for strong interactions. The lowest excitation is gapless phonon, which is characterized by the total density oscillations. The two others are gapped Leggett modes, which correspond relative density fluctuations between sublattices. The collective modes are also reflected in the two-particle spectral functions by sharp peaks. Furthermore, it is found that the two-particle spectral functions satisfy an exact sum-rule, which is directly related to the filling factor (or density of particle). The sum-rule of the spectral functions may be useful to distinguish between the hole-doped and particle-doped superfluid (superconductor) in experiments.

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“…When q is small (q → 0), the matrix elements of two-particle Green functions of zero frequency ω = 0 are proportional to product of two order parameters, namely 47 G II,i j (q, 0)…”

Section: Two-particle Spectral Functionsmentioning

confidence: 99%

Superfluid density and collective modes of fermion superfluid in dice lattice

Wu,

Zhang,

Liu

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Superfluid density, Josephson relation and pairing fluctuations in a multi-component fermion superfluid

Cited by 1 publication

References 38 publications

Superfluid density and collective modes of fermion superfluid in dice lattice

Superfluid density and collective modes of fermion superfluid in dice lattice

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