Split and overlapped binary solitons in optical lattices

TL;DR

This paper investigates the existence, stability, and transitions of split and overlapped bright-bright soliton pairs in binary Bose-Einstein condensates within optical lattices, revealing critical interspecies interactions and potential measurement applications.

Contribution

It introduces a combined variational and numerical analysis of split and overlapped solitons, highlighting transition points and stability criteria in binary BECs with optical lattices.

Findings

Existence of critical interspecies interaction values causing soliton transitions.

Identification of stable split and overlapped soliton configurations.

Potential for using split solitons in scattering length measurements.

Abstract

We analyze the energetic and dynamical properties of bright-bright (BB) soliton pairs in a binary mixture of Bose-Einstein condensates subjected to the action of a combined optical lattice, acting as an external potential for the first species, while modulating the intraspecies coupling constant of the second. In particular, we use a variational approach and direct numerical integrations to investigate the existence and stability of BB solitons in which the two species are either spatially separated (split soliton) or located at the same optical lattice site (overlapped soliton). The dependence of these solitons on the interspecies interaction parameter is explicitly investigated. For repulsive interspecies interaction we show the existence of a series of critical values at which transitions from an initially overlapped soliton to split solitons occur. For attractive interspecies interaction only single direct transitions from split to overlapped BB solitons are found. The possibility to use split solitons for indirect measurements of scattering lengths is also suggested.