Bose glass and superfuid phases of cavity polaritons

TL;DR

This paper models cavity exciton-polariton phases considering realistic disorder, revealing a transition from localized Bose glass to superfluidity via a percolation process, with detailed wavefunction and excitation spectra.

Contribution

It introduces a phase diagram for cavity polaritons incorporating disorder effects, identifying a Bose glass phase and a transition to superfluidity.

Findings

Polaritons undergo a Bose glass phase at intermediate densities.

A percolation process leads to a superfluid phase at higher densities.

The wavefunction and excitation spectra are characterized across phases.

Abstract

We report the calculation of cavity exciton-polariton phase diagram which takes into account the presence of realistic structural disorder. Polaritons are modelled as weakly interacting two-dimensional bosons. We show that with increasing density polaritons first undergo a quasi-phase transition towards a Bose glass: the condensate is localized in at least one minimum of the disorder potential, depending on the value of the chemical potential of the polariton system. A further increase of the density leads to a percolation process of the polariton fluid which gives rise to a Kosterlitz-Thouless phase transition towards superfluidity. The spatial representation of the condensate wavefunction as well as the spectrum of elementary excitations are obtained from the solution of the Gross-Pitaevskii equation for all the phases.