Vortex nucleation as a case study of symmetry breaking in quantum systems

TL;DR

This paper investigates how symmetry breaking occurs during vortex nucleation in rotating Bose-Einstein condensates, highlighting the differences between mean-field and many-body descriptions and emphasizing the role of correlations at critical points.

Contribution

It provides a theoretical analysis of symmetry breaking in quantum many-body systems during vortex formation, emphasizing the importance of correlations at the critical frequency.

Findings

Mean-field theory predicts a symmetry jump via a turbulent phase.

Exact many-body ground state shows strong correlations at the critical point.

Vortex nucleation exemplifies symmetry change in quantum systems.

Abstract

Mean-field methods are a very powerful tool for investigating weakly interacting many-body systems in many branches of physics. In particular, they describe with excellent accuracy trapped Bose-Einstein condensates. A generic, but difficult question concerns the relation between the symmetry properties of the true many-body state and its mean-field approximation. Here, we address this question by considering, theoretically, vortex nucleation in a rotating Bose-Einstein condensate. A slow sweep of the rotation frequency changes the state of the system from being at rest to the one containing one vortex. Within the mean-field framework, the jump in symmetry occurs through a turbulent phase around a certain critical frequency. The exact many-body ground state at the critical frequency exhibits strong correlations and entanglement. We believe that this constitutes a paradigm example of symmetry breaking in - or change of the order parameter of - quantum many-body systems in the course of adiabatic evolution.