Dynamical instability and domain formation in a spin-1 Bose condensate

TL;DR

This paper explains the spontaneous formation of spatial domains in spin-1 Bose condensates as a consequence of dynamical instability, supported by mean field theory and numerical simulations matching experimental observations.

Contribution

It provides a theoretical interpretation of domain formation as dynamical instability in spinor condensates, validated by numerical simulations and experimental data.

Findings

Homogeneous condensate is dynamically unstable for ferromagnetic interactions.

Numerical simulations match experimental results for trapped condensates.

Dynamical instability leads to spontaneous domain formation.

Abstract

We interpret the recently observed spatial domain formation in spin-1 atomic condensates as a result of dynamical instability. Within the mean field theory, a homogeneous condensate is dynamically unstable (stable) for ferromagnetic (antiferromagnetic) atomic interactions. We find this dynamical instability naturally leads to spontaneous domain formation as observed in several recent experiments for condensates with rather small numbers of atoms. For trapped condensates, our numerical simulations compare quantitatively to the experimental results, thus largely confirming the physical insight from our analysis of the homogeneous case.