Single-Bubble Sonoluminescence as Dicke Superradiance at Finite Temperature

TL;DR

This paper models sonoluminescence as a superradiant phase transition in a spin-boson system at finite temperature, explaining how cooperative atomic interactions produce light in liquids under strong sound fields.

Contribution

It introduces a quantum spin-boson model to describe sonoluminescence as a Dicke superradiance phenomenon at finite temperature.

Findings

Superradiant phase transition can occur in sonoluminescence.

Ultrastrong coupling enables cooperative atomic interactions.

Thermal equilibrium conditions support superradiant emission.

Abstract

Sonoluminescence is a process in which a strong sound field is used to produce light in liquids. We explain sonoluminescence as a phase transition from ordinary fluorescence to a superradiant phase. We consider a spin-boson model composed of a single bosonic mode and an ensemble of $N$ identical two-level atoms. We assume that the whole system is in thermal equilibrium with a reservoir at temperature $\beta^{-1}$. We show that, in a ultrastrong-coupling regime, between the two-level atoms and the electromagnetic field it is possible to have a cooperative interaction of the molecules of the gas in the interior of the bubble with the field, generating sonoluminescence.