Amplitude-mode dynamics of polariton condensates

TL;DR

This paper investigates the stability of amplitude excitations in non-equilibrium polariton condensates, revealing their instability to finite wavevector excitations and resulting in density-modulated phases, with analogies to optical and atomic systems.

Contribution

It provides a theoretical analysis of amplitude-mode stability in polariton condensates, highlighting mechanisms leading to phase modulation and drawing analogies to other physical systems.

Findings

Uniform amplitude excitations are unstable to finite wavevector excitations.

Instabilities lead to the formation of density-modulated phases.

Physical processes are analogous to optical parametric oscillators and atomic Bose supernova.

Abstract

We study the stability of collective amplitude excitations in non-equilibrium polariton condensates. These excitations correspond to renormalized upper polaritons and to the collective amplitude modes of atomic gases and superconductors. They would be present following a quantum quench or could be created directly by resonant excitation. We show that uniform amplitude excitations are unstable to the production of excitations at finite wavevectors, leading to the formation of density-modulated phases. The physical processes causing the instabilities can be understood by analogy to optical parametric oscillators and the atomic Bose supernova.