Spin-orbit Coupled Bose-Einstein Condensates in Spin-dependent Optical Lattices

TL;DR

This paper explores how spin-orbit coupling influences the phases and structures of spin-dependent optical lattice Bose-Einstein condensates, revealing complex phenomena like vortex chains and domain wall transformations.

Contribution

It provides a detailed analysis of the phase diagram and ground-state properties of spin-orbit coupled BECs in spin-dependent optical lattices, highlighting novel vortex and domain wall behaviors.

Findings

Transition from Ne9el to Bloch domain walls with increasing spin-orbit coupling

Formation of vortex and antivortex chains at strong spin-orbit coupling

Identification of meron-pair and antimeron-pair lattice structures

Abstract

We investigate the ground-state properties of spin-orbit coupled Bose-Einstein condensates in spin-dependent optical lattices. The competition between the spin-orbit coupling strength and the depth of the optical lattice leads to a rich phase diagram. Without spin-orbit coupling, the spin-dependent optical lattices separate the condensates into alternating spin domains with opposite magnetization directions. With relatively weak spin-orbit coupling, the spin domain wall is dramatically changed from N\'{e}el wall to Bloch wall. For sufficiently strong spin-orbit coupling, vortex chains and antivortex chains are excited in the spin-up and spin-down domains respectively, corresponding to the formation of a lattice composed of meron-pairs and antimeron-pairs in the pseudospin representation. We also discuss how to observe these phenomena in real experiments.