Multiple domain formation induced by modulation instability in two-component Bose-Einstein condensates

TL;DR

This paper investigates how modulation instability causes multiple domain formations in two-component Bose-Einstein condensates, revealing a soliton train-like behavior that explains long-lived spin domains.

Contribution

It demonstrates through numerical simulations that intercomponent mean-field coupling induces modulation instability leading to domain formation, providing new insights into spin domain dynamics.

Findings

Modulation instability causes multiple domain formation.

Domains exhibit soliton train-like behavior.

Long lifetime of spin domains explained.

Abstract

The dynamics of multiple domain formation caused by the modulation instability of two-component Bose-Einstein condensates in an axially symmetric trap are studied by numerically integrating the coupled Gross-Pitaevskii equations. The modulation instability induced by the intercomponent mean-field coupling occurs in the out-of-phase fluctuation of the wave function and leads to the formation of multiple domains that alternate from one domain to another, where the phase of one component jumps across the density dips where the domains of the other exist. This behavior is analogous to a soliton train, which explains the origin of the long lifetime of the spin domains observed by Miesner {it et al.} [Phys. Rev. Lett. {bf 82}, 2228 (1999)].