Fluctuations of spinor Bose-Einstein condensates

TL;DR

This paper develops a theoretical framework to analyze atom number and spin fluctuations in finite-sized cells of spinor Bose-Einstein condensates, applicable to current experimental imaging techniques.

Contribution

It introduces an analytic model for fluctuations in spinor BECs, covering quantum and thermodynamic limits, and validates these with numerical calculations for quasi-2D systems.

Findings

Analytic expressions for fluctuation limits in spinor BECs.

Validation of theoretical limits with numerical simulations.

Behavior of fluctuations across different phases and parameters.

Abstract

We develop theory for fluctuations in atom number and spin within finite-sized cells of a spinor Bose-Einstein condensate. This theory provides a model of measurements that can be performed in current experiments using finite resolution in situ imaging. We develop analytic results for quantum and thermodynamic limits of the fluctuations and apply our theory to the four equilibrium phases of a spin-1 condensate. We then validate these limits and examine the behaviour over a wide parameter regime using numerical calculations specialised to the case of a spinor condensate confined to be quasi-two-dimensional (quasi-2D).