# Observation of Non-equilibrium Motion and Equilibration in Polariton Rings

## TL;DR

This study investigates the dynamics and equilibration of polariton condensates in a ring-shaped microcavity, revealing interaction effects and providing a direct measurement of polariton interactions, supported by theoretical modeling.

## Contribution

It demonstrates macroscopic polariton motion and equilibration in a ring microcavity and measures polariton-polariton interaction strength directly for the first time.

## Key findings

- Polariton condensate forms in a ring trap due to cavity energy gradient.
- Interactions influence the condensate's motion and equilibration.
- Experimental results agree qualitatively with the open-dissipative Gross-Pitaevskii model.

## Abstract

We present a study of the macroscopic dynamics of a polariton condensate formed by non-resonant optical excitation in a quasi-one-dimensional ring-shaped microcavity. The presence of a gradient in the cavity photon energy creates a macroscopic trap for the polaritons in which a single mode condensate is formed. With time- and energy-resolved imaging we show the role of interactions in the motion of the condensate as it undergoes equilibration in the ring. These experiments also give a direct measurement of the polariton-polariton interaction strength above the condensation threshold. Our observations are compared to the open-dissipative one-dimensional Gross-Pitaevskii equation which shows excellent qualitative agreement.