Thouless pumping and trapping of two-component gap solitons

TL;DR

This paper investigates the control of two-component gap solitons in a Bose gas within an optical superlattice, demonstrating how their transport or trapping can be manipulated via interactions and soliton width, with potential experimental applications.

Contribution

It introduces an effective variational model linking soliton width to transport or trapping behavior, enabling controlled manipulation of two-component gap solitons.

Findings

Larger width solitons are transported by Thouless pumping.

Smaller width solitons are trapped in the lattice.

Interaction tuning allows experimental control of soliton behaviors.

Abstract

We study Thouless pumping and arresting of gap solitons in a two-component Bose gas loaded into an optical superlattice. We show that, depending on the atomic interactions and chemical potentials, the two solitons can be simultaneously pumped or trapped, but we also identify regimes where one soliton is pumped and the other arrested. These behaviors can be understood by considering an effective model of the system based on a variational approach, which reveals that the soliton width is a suitable qualifier for the observed behaviours: solitons with a larger width get transported, while solitons with a smaller width get trapped. Since these width can be controlled by tuning interactions, it should be possible to observe all behaviours experimentally.