Quench Induced Vortices in the Symmetry Broken Phase of Liquid $^4$He

TL;DR

This paper investigates vortex formation in superfluid helium-4 during rapid pressure quenches, connecting experimental observations with theories of topological defect formation in symmetry-breaking phase transitions.

Contribution

It provides a new interpretation of observed vortices in superfluid helium-4, supporting theories of defect formation during non-equilibrium phase transitions and suggesting experimental modifications.

Findings

Vortices are observed immediately after pressure quenches.

The vortices are consistent with topological defect formation theories.

Proposed modifications to experiments could clarify vortex formation mechanisms.

Abstract

Motivated by the study of cosmological phase transitions, our understanding of the formation of topological defects during spontaneous symmetry-breaking and the associated non-equilibrium field theory has recently changed. Experiments have been performed in superfluid $^4$He to test the new ideas involved. In particular, it has been observed that a vortex density is seen immediately after pressure quenches from just below the $\lambda$ transition. We discuss possible interpretations of these vortices, conclude they are consistent with our ideas of vortex formation and propose a modification of the original experiments.