Finite momentum condensation in a pumped microcavity

TL;DR

This paper predicts the formation of inhomogeneous quantum condensates at finite momentum in a pumped semiconductor microcavity, revealing collective modes analogous to Cooper pairs and phase diagrams for condensation.

Contribution

It introduces the concept of finite momentum condensation in microcavities and analyzes the conditions for inhomogeneous condensate formation.

Findings

Strong peaks in absorption spectra indicate collective modes.

Instabilities can lead to off-equilibrium condensates at finite momentum.

Phase diagram maps regions of stable and unstable condensate formation.

Abstract

We calculate the absorption spectra of a semiconductor microcavity into which a non-equilibrium exciton population has been pumped. We predict strong peaks in the spectrum corresponding to collective modes analogous to the Cooper modes in superconductors and fermionic atomic gases. These modes can become unstable, leading to the formation of off-equilibrium quantum condensates. We calculate a phase diagram for condensation, and show that the dominant instabilities can be at a finite momentum. Thus we predict the formation of inhomogeneous condensates, similar to Fulde-Ferrel-Larkin-Ovchinnikov states.