Topology of Quantum Grey Soliton in Multi-Component Inhomogeneous Bose-Einstein Condensates

TL;DR

This paper investigates the dispersion and topology of Lieb mode excitations, including grey and bright solitons, in multi-component Bose-Einstein condensates under harmonic confinement, revealing conditions for negative mass regimes and bound states.

Contribution

It introduces a detailed analysis of Lieb mode excitations in inhomogeneous multi-component BECs, highlighting the effects of trap and inter-species interactions on soliton dispersion and bound state formation.

Findings

Trap influences grey soliton dispersion at low momenta.

Hole-like excitations can lead to negative mass regimes.

Inter-species interactions induce shifts and bound states in Lieb modes.

Abstract

We study the dispersion mechanism of Lieb mode excitations of both single and multi component ultra-cold atomic Bose gas, subject to a harmonic confinement through chirp management. It is shown that in some parameter domain, the hole-like excitations lead to the soliton's negative mass regime, arising due to the coupling between chirp momentum and Kohn mode. In low momenta region the trap considerably affects the dispersion of the grey soliton, which opens a new window to observe Lieb-mode excitations. Further, we extend our analysis to binary condensate, which yields usual shape compatible grey-bright soliton pairs. The inter-species interaction induces a shift in the Lieb-mode excitations, where the pair can form a bound state. We emphasize that the present model provides an opportunity to study such excitations in the low momenta regime, as well as the formation of bound state in binary condensate.