Phase separation in a spin-orbit coupled Bose-Einstein condensate

TL;DR

This paper investigates how spin-orbit coupling influences phase separation and miscibility in spin-1 Bose-Einstein condensates under different trapping conditions, revealing critical parameters for phase behavior.

Contribution

It demonstrates the effects of spin-orbit coupling and Rabi terms on phase separation in ferromagnetic and polar BECs in various trap configurations.

Findings

SO coupling causes phase separation in ferromagnetic BECs in a box

SO coupling promotes miscibility in polar BECs

Rabi term induces miscibility regardless of spin interaction type

Abstract

We study a spin-orbit (SO) coupled hyperfine spin-1 Bose-Einstein condensate (BEC) in a quasi-one-dimensional trap. For a SO-coupled BEC in a one-dimensional box, we show that in the absence of the Rabi term, any non-zero value of SO coupling will result in a phase separation among the components for a ferromagnetic BEC, like $^{87}$Rb. On the other hand, SO coupling favors miscibility in a polar BEC, like $^{23}$Na. In the presence of a harmonic trap, which favors miscibility, a ferromagnetic BEC phase separates, provided the SO-coupling strength and number of atoms are greater than some critical value. The Rabi term favors miscibility irrespective of the nature of the spin interaction: ferromagnetic or polar.