Dispersion control for matter waves and gap solitons in optical superlattices

TL;DR

This paper explores how to control dispersion and generate matter-wave gap solitons in Bose-Einstein condensates using optical superlattices, introducing a new interference-based method and demonstrating tunable soliton properties.

Contribution

It introduces a novel interference pattern technique for controlled gap soliton generation and shows how superlattice parameters can tune soliton characteristics.

Findings

Interference pattern method effectively generates gap solitons.

Adjusting superlattice depths tunes soliton density and width.

The method compares favorably with previous moving lattice techniques.

Abstract

We present a numerical study of dispersion manipulation and formation of matter-wave gap solitons in a Bose-Einstein condensate trapped in an optical superlattice. We demonstrate a method for controlled generation of matter-wave gap solitons in a stationary lattice by using an interference pattern of two condensate wavepackets, which mimics the structure of the gap soliton near the edge of a spectral band. The efficiency of this method is compared with that of gap soliton generation in a moving lattice recently demonstrated experimentally by Eiermann et al. [Phys. Rev. Lett. 92, 230401 (2004)]. We show that, by changing the relative depths of the superlattice wells, one can fine-tune the effective dispersion of the matter waves at the edges of the mini-gaps of the superlattice Bloch-wave spectrum and therefore effectively control both the peak density and the spatial width of the emerging gap solitons.