Persistent, controllable circulation of a polariton ring condensate

TL;DR

This paper reports the first direct observation of persistent, controllable circulation in a polariton condensate ring without external driving, demonstrating superfluid-like behavior in a non-equilibrium quantum fluid.

Contribution

It demonstrates persistent, controllable circulation in a polariton condensate ring without ongoing stimulation, supported by a theoretical model explaining the phenomenon.

Findings

Persistent circulation observed without external drive

Circulation can be controlled on demand with a laser pulse

Theoretical model explains how pulses induce circulation

Abstract

Persistent circulation is a canonical effect of superfluidity. In previous experiments, quantized circulation has been observed in polariton condensates, usually far from equilibrium, but persistent current in the absence of any stirring has not been seen. We report here the direct observation of persistent circulation of a polariton condensate with no driving force and with no observable change in time. We can cause the condensate to circulate in either direction on demand using a short laser pulse, after which the condensate continues to circulate for dozens to hundreds of rotations around a ring trap without any further stimulation. Our theoretical model successfully shows how the pulse, despite not carrying any angular momentum, causes the circulation.