Interacting spin-orbit-coupled spin-1 Bose-Einstein condensates

TL;DR

This paper investigates how interactions influence the ground states and excitations of spin-orbit-coupled spin-1 Bose-Einstein condensates, revealing novel stripe phases and excitation spectra due to the interplay of spin interactions and SO coupling.

Contribution

It introduces the effects of atomic interactions on SO-coupled spin-1 BECs, including the emergence of stripe phases and complex excitation spectra, which were not previously explored.

Findings

Ferromagnetic interactions induce stripe phases with modulating patterns.

Double maxon-roton structure found in excitation spectrum.

Phase transitions characterized by spin-tensor density and collective motion.

Abstract

The recent experimental realization of spin-orbit (SO) coupling for spin-1 ultracold atoms opens an interesting avenue for exploring SO-coupling-related physics in large-spin systems, which is generally unattainable in electronic materials. In this paper, we study the effects of interactions between atoms on the ground states and collective excitations of SO-coupled spin-1 Bose-Einstein condensates (BECs) in the presence of a spin-tensor potential. We find that ferromagnetic interaction between atoms can induce a stripe phase exhibiting in-phase or out-of-phase modulating patterns between spin-tensor and zero-spin-component density waves. We characterize the phase transitions between different phases using the spin-tensor density as well as the collective dipole motion of the BEC. We show that there exists a double maxon-roton structure in the Bogoliubov-excitation spectrum, attributed to the three band minima of the SO-coupled spin-1 BEC.