Ground-state properties of a dilute two-dimensional Bose gas

TL;DR

This paper revisits the low-temperature properties of a dilute 2D Bose gas, using hydrodynamic and perturbative methods to derive known and new ground-state properties including condensate density and Tan's contact.

Contribution

It introduces calculations of condensate density and Tan's contact for the first time in this context using Popov's hydrodynamic approach.

Findings

Recovered the known ground-state energy expansion.

Calculated the condensate density.

Determined Tan's contact for the first time.

Abstract

We revisit the problem of the calculation of low-temperature properties for the dilute two-dimensional Bose gas. By using Popov's hydrodynamic approach and perturbation theory on the one-loop level we recover not only the known expansion for the ground-state energy but also calculate for the first time the condensate density and Tan's contact.