Propagating wave-packets and quantised currents in coherently driven polariton superfluids

TL;DR

This paper investigates how propagating polariton wave-packets influence the stability of doubly charged vortices in coherently driven polariton superfluids, revealing velocity-dependent stability linked to the non-quadratic dispersion.

Contribution

It demonstrates that doubly charged vortices are stable only at low velocities due to the polariton dispersion, providing new insights into vortex stability in polariton superfluids.

Findings

Doubly charged vortices are stable at small propagation velocities.

Vortices at higher velocities tend to split and are unstable.

The stability depends on the excitation regime and dispersion properties.

Abstract

We study the properties of propagating polariton wave-packets and their connection to the stability of doubly charged vortices. Wave-packet propagation and related photoluminescence spectra exhibit a rich behaviour dependent on the excitation regime. We show that, because of the non-quadratic polariton dispersion, doubly charged vortices are stable only when initiated in wave-packets propagating at small velocities. Vortices propagating at larger velocities, or those imprinted directly into the polariton optical parametric oscillator (OPO) signal and idler are always unstable to splitting.