Trapping of two-component matter-wave solitons by mismatched optical lattices

TL;DR

This paper investigates the existence, stability, and dynamics of two-component matter-wave solitons in a one-dimensional Bose-Einstein condensate with mismatched optical lattices, revealing conditions for stable trapping and symbiotic stabilization.

Contribution

It introduces a model for two-component BECs with opposite-sign periodic potentials and identifies stability domains for different soliton types, including the novel symbiotic stabilization mechanism.

Findings

Stable soliton complexes are identified for both BB and GB types.

Unstable solitons evolve into oscillatory states.

Increasing inter-species attraction stabilizes complexes even at potential maxima.

Abstract

We consider a one-dimensional model of a two-component Bose-Einstein condensate in the presence of periodic external potentials of opposite signs, acting on the two species. The interaction between the species is attractive, while intra-species interactions may be attractive too [the system of the right-bright (BB) type], or of opposite signs in the two components [the gap-bright (GB) model]. We identify the existence and stability domains for soliton complexes of the BB and GB types. The evolution of unstable solitons leads to the establishment of oscillatory states. The increase of the strength of the nonlinear attraction between the species results in symbiotic stabilization of the complexes, despite the fact that one component is centered around a local maximum of the respective periodic potential.