Polaron in almost ideal molecular Bose-Einstein condensate

Abstract

We discuss properties of a single impurity atom immersed in the spin-1/2 dilute Fermi gas with equal populations of two species in the deep Bose-Einstein condensate (BEC) phase. In this limit, when an almost undepleted BEC of the tightly bound molecules of spin-up and spin-down fermions is formed, we calculate the parameters of an impurity spectrum. It is justified that the leading-order contribution to the impurity energy, while being determined by the two-and three-body scattering processes, is dominated by the former ones.

Weakly-interacting Bose-Bose mixtures from the functional renormalisation group

“…Finally, other related extensions include the study of coherently-coupled condensates [100,101], higher multi-component Bose gases, such as SU(N) Bose gases [102], bipolarons [103], and impurities in superfluid Fermi gases [104,105]. Such systems can be studied with similar techniques to those used in this work.…”

Second root of dilute Bose-Fermi mixtures

“…the UV cutoff is setted up only on fields' spatial dependence. The further consideration in this section, except a modifications associated with the presence of a fermion field, will be held in a spirit of the Hugenholtz and Pines paper [41] and [42]. The first step of their approach, which is well-suited for the calculation of thermodynamics of bosons at weak coupling g b → 0, is the separation of the condensate modes b(x) = b 0 + b(x) with the constraint ´Ld dr b = 0.…”

Mobile impurity in a one-dimensional gas at finite temperatures

“…By q we denote the set q h with the hole filled in. Notice that the determinant in (22) can be presented as…”

“…To theoretically explore the properties of a quantum particle propagating in a one-dimensional medium different schemes and approximations were developed. For instance, various mean-field approaches [20][21][22][23][24] can be used to describe properties of the ground state. Instead, perturbation theories for the weak impurity-gas coupling allows one to describe dynamics of the impurity [25][26][27][28][29].…”