Fragmented and Single Condensate Ground States of Spin-1 Bose Gas

TL;DR

This paper demonstrates that the ground state of a spin-1 Bose gas with antiferromagnetic interactions can be a fragmented condensate in uniform magnetic fields, with controllable transition to a single condensate via magnetic field gradients.

Contribution

It reveals the conditions for fragmented condensate states in spin-1 Bose gases and proposes methods for their detection and manipulation.

Findings

Number fluctuations vary from order N to 1 with magnetization

Fragmented condensate can be converted to a single condensate using magnetic field gradients

Conditions for existence of fragmented states are identified

Abstract

We show that the ground state of a spin-1 Bose gas with an antiferro- magnetic interaction is a fragmented condensate in uniform magnetic fields. The number fluctuations in each spin component change rapidly from being enormous (order $N$) to exceedingly small (order 1) as the magnetization of the system increases. A fragmented condensate can be turned into a single condensate state by magnetic field gradients. The conditions for existence and the method of detecting fragmented states are presented.