Theory for Bose-Einstein condensation of light in nano-fabricated semiconductor microcavities

TL;DR

This paper develops a theoretical framework for Bose-Einstein condensation of light in nano-fabricated semiconductor microcavities, accounting for electron-hole interactions, damping effects, and potential superfluidity signatures.

Contribution

It introduces a comprehensive model for light condensation in semiconductor microcavities, including Coulomb interactions, damping mechanisms, and methods to probe superfluidity and the dynamical Casimir effect.

Findings

Damping of light dynamics can be characterized by a single parameter.

Superfluidity can be probed via scissors mode responses.

Density correlations reveal signatures of the dynamical Casimir effect.

Abstract

We construct a theory for Bose-Einstein condensation of light in nano-fabricated semiconductor microcavities. We model the semiconductor by one conduction and one valence band which consist of electrons and holes that interact via a Coulomb interaction. Moreover, we incorporate screening effects by using a contact interaction with the scattering length for a Yukawa potential and describe in this manner the crossover from exciton gas to electron-hole plasma as we increase the excitation level of the semiconductor. We then show that the dynamics of the light in the microcavities is damped due to the coupling to the semiconductor. Furthermore, we demonstrate that on the electron-hole plasma side of the crossover, which is relevant for the Bose-Einstein condensation of light, this damping can be described by a single dimensionless damping parameter that depends on the external pumping. Hereafter, we propose to probe the superfluidity of light in these nano-fabricated semiconductor microcavities by making use of the differences in the response in the normal or superfluid phase to a sudden rotation of the trap. In particular, we determine frequencies and damping of the scissors modes that are excited in this manner. Moreover, we show that a distinct signature of the dynamical Casimir effect can be observed in the density-density correlations of the excited light fluid.