Persistent currents and quantised vortices in a polariton superfluid

TL;DR

This paper reports the first observation of persistent, quantised vortices in a polariton superfluid, demonstrating dissipationless flow and vortex splitting, supported by theoretical analysis using a Gross-Pitaevskii model.

Contribution

It provides the first experimental evidence of metastable persistent superflows and vortex dynamics in resonantly pumped polariton superfluids, with theoretical support.

Findings

Observation of long-lived quantised vortices lasting at least 80 ps

Demonstration of stable m=2 vortex splitting into two m=1 vortices

Persistence of superfluid flow without continuous driving

Abstract

Semiconductor microcavity polaritons in the optical parametric scattering regime have been recently demonstrated to display a new variety of dissipationless superfluid behaviour. We report the first observation in resonantly pumped exciton polaritons of a metastable persistent superflow carrying quantum of angular momentum, m. The quantised vortex, excited by a weak 2 ps pulsed probe, is shown to last for at least 80 ps, limited only by the leaking outside the cavity. The polariton circulating superfluid persists in the absence of the driving rotating probe with no apparent dissipation. In addition, for a moving superfluid, we show the coherent splitting of a quantised double vortex, with charge m=2, into two singly quantised vortices of m=1. Remarkably, we observe the m=2 vortex to be stable when they are at rest. The experimental results are compared with a theoretical analysis, obtained describing the triggered parametric scattering regime of polaritons via a two-component Gross-Pitaevskii equation, including pump and decay processes.