Gap solitons in Bose-Einstein condensates in linear and nonlinear optical lattices

TL;DR

This paper investigates the properties, stability, and dynamics of gap solitons in Bose-Einstein condensates within combined linear and nonlinear optical lattices, including the discovery of new soliton types and a moving soliton solution.

Contribution

It introduces new types of gap solitons in BECs with combined optical lattices and presents the first analytical and numerical study of moving solitons in this setting.

Findings

Revealed new types of gap solitons.

Analyzed modulational instability of nonlinear plane waves.

Discovered and confirmed a moving soliton solution.

Abstract

Properties of localized states on array of BEC confined to a potential, representing superposition of linear and nonlinear optical lattices are investigated. For a shallow lattice case the coupled mode system has been derived. The modulational instability of nonlinear plane waves is analyzed. We revealed new types of gap solitons and studied their stability. For the first time a moving soliton solution has been found. Analytical predictions are confirmed by numerical simulations of the Gross-Pitaevskii equation with jointly acting linear and nonlinear periodic potentials.