Spontaneous symmetry breaking in spinor Bose-Einstein condensates

TL;DR

This paper develops an analytical model to understand spin dynamics and spontaneous symmetry breaking in spinor Bose-Einstein condensates, aligning well with experimental observations and revealing the mechanisms behind symmetry breaking.

Contribution

It introduces a simplified analytical approach to analyze spinor BEC dynamics and symmetry breaking, providing insights into excitation modes and experimental preparation methods.

Findings

Good quantitative agreement with experimental results.

Identification of excitation modes responsible for symmetry breaking.

Explanation of resonances in atom pair creation efficiency.

Abstract

We present an analytical model for the theoretical analysis of spin dynamics and spontaneous symmetry breaking in a spinor Bose-Einstein condensate (BEC). This allows for an excellent intuitive understanding of the processes and provides good quantitative agreement with experimental results in Phys. Rev. Lett. 105, 135302 (2010). It is shown that the dynamics of a spinor BEC initially prepared in an unstable Zeeman state mF=0 (|0>) can be understood by approximating the effective trapping potential for the state |+-1> with a cylindrical box potential. The resonances in the creation efficiency of these atom pairs can be traced back to excitation modes of this confinement. The understanding of these excitation modes allows for a detailed characterization of the symmetry breaking mechanism, showing how a twofold spontaneous breaking of spatial and spin symmetry can occur. In addition a detailed account of the experimental methods for the preparation and analysis of spinor quantum gases is given.