Bright solitons in spin-orbit-coupled Bose-Einstein condensates

TL;DR

This paper investigates bright solitons in spin-orbit-coupled Bose-Einstein condensates, revealing their properties, symmetries, and how their shapes change with velocity due to broken Galilean invariance.

Contribution

It provides the first analysis of both stationary and moving bright solitons in spin-orbit-coupled BECs, highlighting their unique symmetries and velocity-dependent shape changes.

Findings

Stationary bright solitons are ground states with well-defined spin-parity.

Moving bright solitons change shape with velocity due to lack of Galilean invariance.

Number of nodes in solitons depends on spin-orbit coupling strength.

Abstract

We study bright solitons in a Bose-Einstein condensate with a spin-orbit coupling that has been realized experimentally. Both stationary bright solitons and moving bright solitons are found. The stationary bright solitons are the ground states and possess well-defined spin-parity, a symmetry involving both spatial and spin degrees of freedom; these solitons are real valued but not positive definite, and the number of their nodes depends on the strength of spin-orbit coupling. For the moving bright solitons, their shapes are found to change with velocity due to the lack of Galilean invariance in the system.