Universal coarsening dynamics in a 2D superfluid

Speaker: Andrew Groszek
Affiliation: University of Queensland

Abstract

We study the phase ordering dynamics of a 2D Bose gas following a quench into the superfluid phase, using numerical simulations within the classical field methodology. We explore the effect of dissipation on the dynamics by tuning the model between its fully conservative and fully dissipative limits. We find clear evidence for universal behaviour, regardless of the dissipation strength. This universal behaviour manifests as a fractal-like growth of phase domains in time, accompanied by a power-law growth of the correlation length ~t(1/z), where z is the dynamical exponent. We find that the exponent z displays corrections to the generally expected value of z=2 for this system; in particular, we find that z<2 in the conservative limit. We also explore the dependence of z on the superfluid temperature, and find that the dynamical exponent returns to a value of z~2 in the limit of low temperatures. We show that the corrections to z=2 that we observe may be attributable to a power-law vortex mobility arising from interactions between vortices and sound waves in the system.