Topological constraints on the dynamics of vortex formation in a two-dimensional quantum fluid

TL;DR

This paper investigates how topological constraints influence vortex formation and annihilation in a two-dimensional quantum fluid of light, revealing mechanisms unique to non-stationary, compressible systems.

Contribution

It introduces new dynamical mechanisms for vortex behavior driven by topological constraints in a non-stationary quantum fluid of light.

Findings

Identification of two vortex formation mechanisms

Both mechanisms described by fold-Hopf bifurcation

Discovery of a highly efficient vortex annihilation process

Abstract

We present experimental and theoretical results on formation of quantum vortices in a laser beam propagating in a nonlinear medium. Topological constrains richer than the mere conservation of vorticity impose an elaborate dynamical behavior to the formation and annihilation of vortex-antivortex pairs. We identify two such mechanisms, both described by the same fold-Hopf bifurcation. One of them is particularly efficient although it is not observed in the context of liquid helium films or stationary systems because it relies on the compressible nature of the fluid of light we consider and on the non-stationarity of its flow.