On-demand generation of dark-bright soliton trains in Bose-Einstein condensates

TL;DR

This paper presents a method to generate dark-bright soliton trains in two-component Bose-Einstein condensates using initial configurations, with analytical solutions validated by numerical simulations.

Contribution

It generalizes previous single-component soliton creation methods to two-component BECs and derives analytical expressions for dark-bright soliton trains from specific initial conditions.

Findings

Initial box size and filling control soliton number and velocity.

Initial phase determines the parity of the soliton solutions.

Analytical results agree well with numerical simulations in various trapping conditions.

Abstract

The controlled creation of dark-bright (DB) soliton trains in multi-component Bose-Einstein condensates (BECs) is a topic of ongoing interest. In this work we generalize earlier findings on the creation of dark soliton trains in single-component BECs [A. Romero-Ros et al., Phys. Rev. A 103, 023329 (2021)] to two-component BECs. By choosing suitable filled box-type initial configurations (FBTCs) and solving the direct scattering problem for the defocusing vector nonlinear Schr\"odinger equation with nonzero boundary conditions we obtain analytical expressions for the DB soliton solutions produced by a general FBTC. It is found that the size of the initial box and the amount of filling directly affects the number, size, and velocity of the solitons, while the initial phase determines the parity (even or odd) of the solutions. Our analytical results are compared to direct numerical integration of the coupled Gross-Pitaevskii equations, both in the absence and in the presence of a harmonic trap, and an excellent agreement between the two is demonstrated.