Ground states of trapped spin-1 condensates in magnetic field

TL;DR

This paper analyzes the ground states of spin-1 Bose-Einstein condensates in a harmonic trap under magnetic fields, revealing phase separation and spatial magnetization patterns influenced by interactions and atom number.

Contribution

It provides a detailed mean-field analysis of spatial and spin structures of trapped spin-1 condensates, highlighting the effects of magnetic fields and atom number on phase separation.

Findings

Antiferromagnetic condensates can separate into three phases.

Ferromagnetic condensates can form two distinct phases.

Magnetization distribution depends on magnetic interactions and trap conditions.

Abstract

We consider a spin-1 Bose-Einstein condensate trapped in a harmonic potential under the influence of a homogeneous magnetic field. We investigate spatial and spin structure of the mean-field ground states under constraints on the number of atoms and the total magnetization. We show that the trapping potential can make the antiferromagnetic condensate separate into three, and ferromagnetic condensate into two distinct phases. In the ferromagnetic case, the magnetization is located in the center of the harmonic trap, while in the antiferromagnetic case magnetized phases appear in the outer regions. We describe how the transition from the Thomas-Fermi regime to the single-mode approximation regime with decreasing number of atoms results in the disappearance of the domains. We suggest that the ground states can be created in experiment by adiabatically changing the magnetic field strength.