Superfluidity of an interacting trapped quasi-2D Bose gas

TL;DR

This paper studies a trapped quasi-2D Bose gas, revealing superfluidity through changes in scissors-mode oscillation frequencies and demonstrating quasi-long-range order below the BKT transition.

Contribution

It provides microscopic evidence of superfluidity in a trapped quasi-2D Bose gas by analyzing scissors-mode oscillations across the BKT transition.

Findings

Irrotational mode frequency varies across the BKT transition

System exhibits quasi-long-range order below the transition

Superfluidity evidenced by changes in collective oscillations

Abstract

We investigate the harmonically trapped interacting Bose gas in a quasi-2D geometry using the classical field method. The system exhibits quasi-long-range order and non-classical rotational inertia at temperatures below the Berezinskii-Kosterlitz-Thouless cross-over to the superfluid state. In particular, we compute the scissors-mode oscillation frequencies and find that the irrotational mode changes its frequency as the temperature is sweeped across the cross-over thus providing microscopic evidence for the emergence of superfluidity.