Symmetry breaking and fluctuations within stochastic mean-field dynamics: importance of initial quantum fluctuations

TL;DR

This paper investigates how stochastic mean-field dynamics, which include initial quantum fluctuations, can effectively model symmetry breaking and fluctuations in the Lipkin-Meshkov-Glick model, especially across different coupling regimes.

Contribution

It demonstrates that incorporating initial quantum fluctuations into stochastic mean-field dynamics accurately reproduces quantum behavior, surpassing standard mean-field methods.

Findings

Perfectly reproduces exact quantum dynamics in weak coupling

Describes gross properties of quantum evolution above symmetry breaking threshold

Highlights importance of initial fluctuations in modeling quantum symmetry breaking

Abstract

Dynamics of spontaneous symmetry breaking and fluctuations in the Lipkin-Meshkov-Glick model are investigated in a stochastic mean-field approach. Different from the standard mean-field, in the stochastic approach, initial state fluctuations, are incorporated. In weak coupling, the approach perfectly reproduces the exact quantal dynamics. On the other hand, for increasing coupling strength, above the symmetry breaking threshold, the approach provides description of gross properties (i.e. time averaged behavior) of the exact quantal evolution.