From Nodeless Clouds and Vortices to Gray Rings and Symmetry-Broken States in Two-Dimensional Polariton Condensates

TL;DR

This paper investigates the existence, stability, and dynamics of various nonlinear excitations in two-dimensional polariton condensates, revealing stable vortex and gray ring states and their instabilities, contrasting with atomic BEC behavior.

Contribution

It demonstrates the existence of stable gray ring states and analyzes their stability and symmetry-breaking instabilities in polariton condensates, extending understanding beyond atomic BECs.

Findings

Stable vortex and gray ring states identified in polariton condensates.

Instabilities lead to pattern formations with triangular or quadrupolar symmetry.

Contrasts with energy-conserving atomic BECs in stability and excitation behavior.

Abstract

We consider the existence, stability and dynamics of the nodeless state and fundamental nonlinear excitations, such as vortices, for a quasi-two-dimensional polariton condensate in the presence of pumping and nonlinear damping. We find a series of interesting features that can be directly contrastedto the case of the typically energy-conserving ultracold alkali-atom Bose-Einstein condensates (BECs). For sizeable parameter ranges, in line with earlier findings, the nodeless state becomes unstable towards the formation of {\em stable} nonlinear single or multi-vortex excitations. The potential instability of the single vortex is also examined and is found to possess similar characteristics to those of the nodeless cloud. We also report that, contrary to what is known, e.g., for the atomic BEC case, {\it stable} stationary gray rings (that can be thought of as radial forms of a Nozaki-Bekki hole) can be found for polariton condensates in suitable parametric regimes. In other regimes, however, these may also suffer symmetry breaking instabilities. The dynamical, pattern-forming implications of the above instabilities are explored through direct numerical simulations and, in turn, give rise to waveforms with triangular or quadrupolar symmetry.