Stability and excitations of spontaneous vortices in polariton condensates

We study the dynamics of spontaneously formed vortices in incoherently pumped homogeneous microcavity polariton condensates (MPC). We find vortices are stable and appear spontaneously without stirring or rotating MPCs by the numerical modeling using complex Gross–Pitaevskii equation. The center of the vortex core contains some background of reservoir polaritons and the visibility increases with the pump strength. The vortex radius is inversely proportional to the square root of the condensate density or the pump strength. Finally, vortices formed by low pumping power exhibit short lifetime because of the existence of excitations without costing energy.