Universal dynamics in the expansion of vortex clusters in a dissipative two-dimensional superfluid

Abstract

A large ensemble of quantum vortices in a superfluid may itself be treated as a novel kind of fluid that exhibits anomalous hydrodynamics. In this talk, I’ll consider the dynamics of vortex clusters under thermal friction and present an analytic solution that uncovers a new universality class in the out-of-equilibrium dynamics of dissipative superfluids. The long-time dynamics of the vorticity distribution is universal in the form of an expanding Rankine vortex (i.e., top-hat distribution) independent of initial conditions. This highlights a fundamentally different decay process to classical fluids, where the Rankine vortex is forbidden by viscous diffusion. Experimental results of expanding vortex clusters in a quasi-two-dimensional Bose-Einstein condensate are in excellent agreement with the vortex fluid theory predictions. Our theoretical, numerical, and experimental results establish the validity of the vortex fluid theory for superfluid systems.

Date
Mar 18, 2021
Location
Online (due to COVID)
Oliver Stockdale
Oliver Stockdale
PhD student in Physics

My research interests include ultracold quantum gases, entanglement detection, entropic uncertainty relations, and superfluidity