On Berezinskii-Kosterlitz-Thouless phase transition and universal breathing mode in two dimensional photon gas

TL;DR

This paper discusses the potential to observe the Berezinskii-Kosterlitz-Thouless phase transition and a universal breathing mode in a two-dimensional photon gas system, proposing experimental modifications for verification.

Contribution

It introduces a method to detect the BKT transition in photon gases via superfluid density jumps and highlights the observation of a universal breathing mode.

Findings

Universal breathing mode can be observed in 2D photon gas.

Modifications enable detection of BKT transition through superfluid density jump.

Experimental setup adjustments are proposed for observing phase transition.

Abstract

A system of two dimensional photon gas has recently been realized experimentally. It is pointed out that this setup can be used to observe a universal breathing mode of photon gas. It is shown that a modification in the experimental setup would open up a possibility of observing the Berezinskii-Kosterlitz-Thouless (BKT) phase transition in such a system. It is shown that the universal jump in the superfluid density of light in the output channel can be used as an unambiguous signature for the experimental verification of the BKT transition.