Spontaneous rotation in one-dimensional systems of cold atoms

TL;DR

This paper predicts that in one-dimensional trapped Bose gases with multiple energy bands, interactions and quantum fluctuations can lead to a ground state with spontaneous rotation, breaking reflection symmetry.

Contribution

It introduces a theoretical framework combining Ginzburg-Landau and bosonization techniques to predict spontaneous rotation in multiband 1D Bose gases.

Findings

Spontaneous rotation state with finite angular momentum predicted

Reflection symmetry is spontaneously broken in the ground state

Higher-energy bands influence the ground state properties

Abstract

We theoretically study harmonically trapped one-dimensional Bose gases (e.g., Li, Na, K, Rb, etc.) with multibands occupied, focusing on effects of higher-energy bands. Combining the Ginzburg-Landau theory with the bosonization techniques, we predict that the repulsive interaction between higher-band bosons and the quantum fluctuation can induce the ground state with a finite angular momentum around the trapped axis. In this state, the Z_2 reflection symmetry (clockwise or anticlockwise rotations) is spontaneously broken.