Role of the confinement-induced effective range in the thermodynamics of a strongly correlated Fermi gas in two dimensions

Abstract

We theoretically investigate the thermodynamic properties of a strongly correlated twodimensional Fermi gas with a confinement-induced negative effective range of interactions, which is described by a two-channel model Hamiltonian. By extending the many-body T -matrix approach by Nozières and Schmitt-Rink to the two-channel model, we calculate the equation of state in the normal phase and present several thermodynamic quantities as functions of temperature, interaction strength, and effective range. We find that there is a non-trivial dependence of thermodynamics on the effective range. In experiment, where the effective range is set by the tight axial confinement, the contribution of the effective range becomes non-negligible as the temperature decreases down to the degenerate temperature. We compare our finite-range results with recent measurements on the density equation of state, and show that the effective range has to be taken into account for the purpose of a quantitative understanding of the experimental data. arXiv:1909.03578v1 [cond-mat.quant-gas]

Pseudogap regime of a strongly interacting two-dimensional Fermi gas with and without confinement-induced effect range of interactions

“…We start our calculation of the many-body Green's function within a two-channel model of the 2D interacting Fermi gas in the normal state, described by the Hamiltonian [42][43][44][45]:…”

“…Through the thermodynamic potential we can calculate the thermodynamic properties of the system, starting with the pressure EoS P = Ω/V , the energy E = −T S + Ω + µN , and the entropy S = − (∂Ω/∂T ) µ [45]. The specific heat at constant volume is given by…”

Thermodynamic properties of two-dimensional charged spin-1/2 Fermi gases

“…[26] On the theoretical side, the evolution from a superfluid state with large Cooper pairs to a superfluid state with compact molecules has been studied in the 2D attracting fermion system. [27] Recently, the thermodynamic quantities as functions of temperature, interaction strength and effective range, [28] and the role of a negative confinement-induced effective range on many-body pairing above the superfluid transition [29] in the strongly correlated 2D Fermi gases are also in-vestigated. Experimentally, 2D Fermi gases have been solved their production, [30][31][32] pairing, [33,34] pseudogap, [35] pressure profiles, [36] the Berezinskii-Kosterlitz-Thouless transition, [37] etc.…”