Spatial Coherence of a polariton condensate in 1D acoustic lattice

TL;DR

This paper investigates the factors influencing the spatial coherence of a polariton condensate in a 1D acoustic lattice, concluding that non-equilibrium effects and multiple mode occupation best explain experimental observations.

Contribution

It provides a detailed analysis of how different mechanisms affect spatial coherence and identifies non-equilibrium effects as key to understanding experimental data.

Findings

Non-equilibrium effects explain the shape of g1(x)

Approximately 10 modes are occupied in the experimental system

Polariton-polariton interactions and disorder are less influential

Abstract

Several mechanisms are discussed which could determine the spatial coherence of a polariton condensate confined to a one dimensional wire. The mechanisms considered are polariton-polariton interactions, disorder scattering and non-equilibrium occupation of finite momentum modes. For each case, the shape of the resulting spatial coherence function g1(x) is analysed. The results are compared with the experimental data on a polariton condensate in an acoustic lattice from [E. A. Cerda-Mendez et al, Phys. Rev. Lett. 105, 116402 (2010)]. It is concluded that the shape of g1(x) can only be explained by non-equilibrium effects, and that ~10 modes are occupied in the experimental system.