The Virial Expansion of a Dilute Bose Gas in Two Dimensions

TL;DR

This paper develops a systematic perturbative virial expansion for a dilute two-dimensional Bose gas using two-body scattering phase shifts, calculating thermodynamic functions and discussing experimental observability.

Contribution

It introduces a second-order virial expansion framework for 2D dilute Bose gases based on scattering phase shifts, extending previous models.

Findings

Thermodynamic functions calculated to second order.

Universal low energy phase shift limit discussed.

Applicability to quasi-2D atomic gases in traps.

Abstract

In terms of the s-wave phase shift of the two-body scattering at thermal wavelength, a systematic perturbative expansion of the virial coefficients is developed for a two-dimensional dilute system of bosons in its gaseous phase at low temperature. The thermodynamic functions are calculated to the second order of the expansion parameter. The observability of the universal low energy limit of the two-dimensional phase shift with a quasi-two dimensional atomic gas in an anisotropic trap is discussed.