Bright solitons and self-trapping with a BEC of cold atoms in driven tilted optical lattices

TL;DR

This paper proposes a method to generate bright matter solitons in a Bose-Einstein condensate within a driven tilted optical lattice by tuning the phase of the driving field, revealing regimes of self-focusing, soliton formation, and incoherent self-trapping.

Contribution

It introduces a novel approach to control soliton formation in BECs using phase-adjusted driven optical lattices, identifying critical interaction strengths for different dynamical regimes.

Findings

Bright solitons can be created by phase tuning the driving field.

Self-focusing occurs when interactions exceed a critical value.

High interactions lead to incoherent self-trapping instead of solitons.

Abstract

We suggest a method for creating bright matter solitons by loading a BEC of atoms in a driven tilted optical lattice. It is shown that one can realize the self-focussing regime for the wave-packet dynamics by properly adjusting the phase of the driving field with respect to the phase of Bloch oscillations. If atom-atom interactions are larger than some critical value $g_{min}$, this self-focussing regime is followed by the formation of bright solitons. Increasing the interactions above another critical value $g_{max}$ makes this process unstable. Instead of soliton formation one now meets the phenomenon of incoherent self-trapping. In this regime a fraction of atoms is trapped in incoherent localized wave-packets, while the remaining atoms spread ballistically.