Localized modes of binary mixtures of Bose-Einstein condensates in nonlinear optical lattices

TL;DR

This paper explores the existence, types, and stability of localized modes in a two-component Bose-Einstein condensate within nonlinear optical lattices, revealing new soliton solutions and delocalization transitions.

Contribution

It introduces new types of solitons in nonlinear optical lattices and analyzes their stability and symmetry properties using analytical and numerical methods.

Findings

Discovery of new soliton types in nonlinear optical lattices

Identification of stability conditions for localized modes

Observation of delocalizing transition related to lattice strength

Abstract

The properties of the localized states of a two component Bose-Einstein condensate confined in a nonlinear periodic potential [nonlinear optical lattice] are investigated. We reveal the existence of new types of solitons and study their stability by means of analytical and numerical approaches. The symmetry properties of the localized states with respect to the NOL are also investigated. We show that nonlinear optical lattices allow the existence of bright soliton modes with equal symmetry in both components, bright localized modes of mixed symmetry type, as well as, dark-bright bound states and bright modes on periodic backgrounds. In spite of the quasi 1D nature of the problem, the fundamental symmetric localized modes undergo a delocalizing transition when the strength of the nonlinear optical lattice is varied. This transition is associated with the existence of an unstable solution, which exhibits a shrinking (decaying) behavior for slightly overcritical (undercritical) variations in the number of atoms.