Dynamical instability of a non-equilibrium exciton-polariton condensate

TL;DR

This study experimentally observes the dynamical instability in non-equilibrium exciton-polariton condensates, confirming theoretical predictions and revealing the importance of reservoir dynamics and particle currents in the instability mechanism.

Contribution

First direct experimental observation of dynamical instability in non-equilibrium polariton condensates with quantitative agreement to open-dissipative Gross-Pitaevskii simulations.

Findings

Reservoir dynamics are in the strongly nonadiabatic regime.

The transition from stable to unstable fluid depends on reservoir-mediated instability.

Particle currents induced by finite pump spot size influence system stability.

Abstract

By imaging single-shot realizations of an organic polariton quantum fluid, we observe the long-sought dynamical instability of non-equilibrium condensates. Without any free parameters, we find an excellent agreement between the experimental data and a numerical simulation of the open-dissipative Gross-Pitaevskii equation, which allows us to draw several important conclusions about the physics of the system. We find that the reservoir dynamics are in the strongly nonadiabatic regime, which renders the complex Ginzburg-Landau description invalid. The observed transition from stable to unstable fluid can only be explained by taking into account the specific form of reservoir-mediated instability as well as particle currents induced by the finite extent of the pump spot.