Spontaneous formation of bright solitons in self-localized impurities in Bose-Einstein condensate

TL;DR

This paper investigates how bright solitons spontaneously form in impurity components of Bose-Einstein condensates due to effective attraction caused by strong correlations, with temperature and interaction strength affecting their stability.

Contribution

It demonstrates the spontaneous formation of bright solitons in BEC-impurity mixtures driven by anomalous correlations, using time-dependent Hartree-Fock-Bogoliubov theory.

Findings

Bright solitons form spontaneously under strong correlations.

Higher temperatures cause soliton decay due to dissipation.

Sudden impurity-boson interaction increases produce soliton trains via modulational instability.

Abstract

We study the formation of bright solitons in the impurity component of Bose-Einstein condensate (BEC)-impurity mixture by using the time-dependent Hartree-Fock-Bogoliubov theory. While we assume the boson-boson and impurity-boson interactions to be effectively repulsive, their character can be changed spontaneously from repulsive to attractive in the presence of strong anomalous correlations. In such a regime the impurity component becomes a system of effectively attractive atoms leading automatically to the generation of bright solitons. We find that this soliton decays at higher temperatures due to the dissipation induced by the impurity-host and host-host interactions. We show that after a sudden increase of the impurity-boson strength a train of bright solitons is produced and this can be interpreted in terms of the modulational instability (MI) of the time-dependent impurity wave function.