Sculpting quasi one-dimensional Bose-Einstein condensate to generate calibrated matter-waves

TL;DR

This paper theoretically investigates how a Hermite-Gaussian dimple trap can manipulate the dynamics of a quasi-one-dimensional Bose-Einstein condensate, leading to the formation of matter-wave solitons and complex density structures.

Contribution

It introduces a method to control BEC dynamics using Hermite-Gaussian traps, revealing new phenomena like soliton trains and density bumps in non-equilibrium states.

Findings

Red/blue HGdT induces density bumps/dips in BEC.

Switching off HGdT creates gray/dark soliton trains.

Shape of solitons depends on HGdT geometry.

Abstract

We explore theoretically how to tune the dynamics of a quasi one-dimensional harmonically trapped Bose-Einstein condensate (BEC) due to an additional red- and blue-detuned Hermite-Gaussian dimple trap (HGdT). To this end we study a BEC in a highly non-equilibrium state, which is not possible in a traditional harmonically confined trap. Our system is modeled by a time-dependent Gross-Pitaevskii equation, which is numerically solved by the Crank-Nicolson method in both imaginary and real time. For equilibrium, we obtain a condensate with two bumps/dips which are induced by the chosen TEM$_{01}$ mode for the red/blue-detuned HGdT, respectively. Afterwards, in time-of-flight dynamics, we examine the adherence/decay of the two bumps/dips in the condensate, which are induced by the still present red/blue-detuned HGdT, respectively. On the other hand, once the red/blue HGdT potential is switched off, shock-waves or bi-trains of gray/dark pair-solitons are created. During this process it is found that the generation of gray/dark pair-solitons bi-trains are generic phenomena of collisions of moderately/fully fragmented BEC. Additionally, it turns out that the special shape of generated solitons in the harmonically trapped BEC firmly depends upon the geometry of the HGdT.