Symmetry Breaking with a Slant: Topological Defects after an Inhomogeneous Quench

TL;DR

This paper demonstrates that in inhomogeneous phase transitions, the density of topological defects decreases significantly when the quench front moves slower than the phase front speed, with implications for experimental control.

Contribution

It introduces a new understanding of defect suppression in inhomogeneous quenches based on the relative velocities of phase front and quench propagation.

Findings

Defect density is suppressed when quench velocity is below phase front speed.

Phase front speed is related to healing length and relaxation time.

Implications for controlling defect formation in experiments.

Abstract

We show that, in second-order phase transformations induced by an inhomogeneous quench, the density of topological defects is drastically suppressed as the velocity with which the quench propagates becomes smaller than the speed at which the front of the broken symmetry phase spreads. The velocity of the broken symmetry phase front is approximately given by the ratio of the healing length to relaxation time at freeze-out, that is at the instant when the critical slowing down results in a transition from the adiabatic to the impulse behavior in the order parameter. Experimental implications are briefly discussed.