Quantum Vortex Formation in the "Rotating Bucket'' Experiment with Polariton Condensates

Abstract: The appearance of quantised vortices in the classical rotating bucket'' experiments of liquid helium and ultracold dilute gases provides the means for fundamental and comparative studies of different superfluids. Here, we realize therotating bucket'' experiment for optically trapped quantum fluid of light based on exciton-polariton Bose-Einstein condensate in semiconductor microcavity. We utilise the beating note of two frequency-stabilized single-mode lasers to generate an asymmetric time-periodic rotating, non-resonant excitation profile that both injects and stirs the condensate through its interaction with a background exciton reservoir. The pump-induced external rotation of the condensate results in the appearance of a co-rotating quantised vortex. We investigate the rotation-frequency dependence and reveal the range of stirring frequencies (from 1 to 4 GHz) which favors quantised vortex formation. We describe the phenomenology using the generalised Gross-Pitaevskii equation. Our results enable the study of polariton superfluidity on a par with other superfluids, as well as deterministic, all-optical control over structured nonlinear light.