Spontaneous rotating vortex rings in a parametrically driven polariton fluid

¹ Department of Physics, University of Warwick - Coventry, CV4 7AL, UK
² TCM Group, Cavendish Laboratory, University of Cambridge - Cambridge, CB3 0HE, UK
³ Rudolf Peierls Centre for Theoretical Physics, University of Oxford - Oxford, OX1 3NP, UK
⁴ Departamento de Física Teórica de la Materia Condensada & Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid - Madrid 28049, Spain
⁵ NNL, Istituto Nanoscienze-CNR - Via Arnesano, 73100 Lecce, Italy
⁶ Department of Physics and Astronomy, University College London - Gower Street, London, WC1E 6BT, UK

^(a) joh28@cam.ac.uk
^(b) andrew.balin@physics.ox.ac.uk
^(c) m.szymanska@ucl.ac.uk

Received: 6 February 2015
Accepted: 2 June 2015

Abstract

We present the theoretical prediction of spontaneous rotating vortex rings in a parametrically driven quantum fluid of polaritons – coherent superpositions of coupled quantum well excitons and microcavity photons. These rings arise not only in the absence of any rotating drive, but also in the absence of a trapping potential, in a model known to map quantitatively to experiments. We begin by proposing a novel parametric pumping scheme for polaritons, with circular symmetry and radial currents, and characterize the resulting nonequilibrium condensate. We show that the system is unstable to spontaneous breaking of circular symmetry via a modulational instability, following which a vortex ring with large net angular momentum emerges, rotating in one of two topologically distinct states. Such rings are robust and carry distinctive experimental signatures, and so they could find applications in the new generation of polaritonic devices.