Phase sensitive two mode squeezing and photon correlations from exciton superfluid

TL;DR

This paper proposes phase-sensitive measurements of photon correlations and squeezing spectra as definitive experiments to detect exciton superfluidity in semiconductor bilayer systems, providing clearer evidence than photoluminescence alone.

Contribution

It introduces phase-sensitive two-mode squeezing and photon correlation measurements as new methods to identify exciton superfluidity.

Findings

Photons emitted are always in a two-mode squeezed state between nd -irections.

Photon statistics are super-Poissonian with two-photon bunching.

Future experiments could conclusively confirm exciton superfluidity.

Abstract

There have been experimental and theoretical studies on Photoluminescence (PL) from possible exciton superfluid in semiconductor electron-hole bilayer systems. However, the PL contains no phase information and no photon correlations, so it can only lead to suggestive evidences. It is important to identify smoking gun experiments which can lead to convincing evidences. Here we study two mode phase sensitive squeezing spectrum and also two photon correlation functions. We find the emitted photons along all tilted directions are always in a two mode squeezed state between $ \vec{k} $ and $ - \vec{k} $. There are always two photon bunching, the photon statistics is super-Poissonian. Observing these unique features by possible future phase sensitive homodyne experiment and HanburyBrown-Twiss type of experiment could lead to conclusive evidences of exciton superfluid in these systems.