Second-order virial expansion for an atomic gas in a harmonic waveguide

TL;DR

This paper extends the virial expansion to cold atomic gases in a harmonic waveguide near a Feshbach resonance, incorporating atom-molecule interactions and defining scattering phase-shifts in an inhomogeneous setting.

Contribution

It introduces a second-order virial expansion framework for atomic gases in a waveguide, including a generalized Beth-Uhlenbeck formula for inhomogeneous systems.

Findings

Extended virial expansion to waveguide geometries

Defined scattering phase-shift in an inhomogeneous environment

Generalized Beth-Uhlenbeck formula for these systems

Abstract

The virial expansion for cold two-component Fermi and Bose atomic gases is considered in the presence of a waveguide and in the vicinity of a Feshbach resonance. The interaction between atoms and the coupling with the Feshbach molecules is modeled using a quantitative separable two-channel model. The scattering phase-shift in an atomic waveguide is defined. This permits us to extend the Beth-Uhlenbeck formula for the second-order virial coefficient to this inhomogeneous case.