Phase transitions and elementary excitations in spin-1 Bose gases with Raman-induced spin-orbit coupling

TL;DR

This paper explores the phase diagram and excitations of spin-1 Bose gases with Raman-induced spin-orbit coupling, revealing new stripe phases, phase transitions, and complex excitation spectra with potential experimental observations.

Contribution

It identifies novel stripe condensation phases and analyzes their phase transitions and excitation spectra, advancing understanding of spin-orbit coupled Bose gases.

Findings

Identification of three stripe phases breaking U(1) and translation symmetry

Prediction of tricritical points in phase transitions

Rich roton-maxon excitation structures indicating crystalline order tendencies

Abstract

We study the ground state phase diagram and the quantum phase transitions in spin-1 Bose gases with Raman induced spin-orbit coupling. In addition to the Bose-Einstein condensates with uniform density, three types of stripe condensation phases that simultaneously break the U(1) symmetry and the translation symmetry are identified. The transitions between these phases are investigated, and the occurrences of the various tricritical points are predicted. The excitation spectra in the plane-wave phase and the zero-momentum phase show rich roton-maxon structures, and their instabilities indicate the tendency to develop the crystalline order. We propose the atomic gas of $^{23}$Na could be a candidate for observing the stripe condensate with high contrast fringes.