Nonlinear dynamics of a dense two-dimensional dipolar exciton gas

TL;DR

This paper models the nonlinear dynamics of a dense 2D dipolar exciton gas, revealing rapid initial expansion due to dipole pressure and implications for Bose-Einstein condensation observation.

Contribution

It introduces a simple model that accurately predicts exciton gas behavior and highlights the importance of trapping for quantum effects.

Findings

Initial fast expansion due to dipole pressure

Slow diffusion phase observed

Implications for exciton trapping needed for BEC

Abstract

We use a simple model to describe the nonlinear dynamics of a dense two dimensional dipolar exciton gas. The model predicts an initial fast expansion due to dipole-dipole pressure, followed by a much slower diffusion. The model is in very good agreement with recent experimental results. We show that the dipole pressure induced expansion strongly constrains the time available for achieving and observing Bose-Einstein quantum statistical effects, indicating a need for spatial exciton traps. We also suggest that nonlinear ballistic exciton transport due to the strong internal dipole pressure is readily achievable.