Vortex-bright solitons in a spin-orbit coupled spin-$1$ condensate

TL;DR

This paper investigates vortex-bright solitons in a spin-orbit-coupled spin-1 Bose-Einstein condensate, revealing their ground states, stability, and collision behaviors through variational and numerical methods.

Contribution

It introduces a detailed analysis of vortex-bright solitons in a spin-1 SO-coupled BEC, including their ground states, asymmetric forms, and collision dynamics, which were not previously characterized.

Findings

Ground state is radially symmetric for weak interactions.

Strong ferromagnetic interactions lead to asymmetric vortex-bright solitons.

Collision outcomes depend on phase difference and velocity, showing classical-like behavior at low velocities.

Abstract

We study the vortex-bright solitons in a quasi-two-dimensional spin-orbit-coupled (SO-coupled) hyperfine spin-1 three-component Bose-Einstein condensate (BEC) using variational method and numerical solution of a mean-field model. The ground state of these vortex-bright solitons is radially symmetric for weak ferromagnetic and polar interactions. For a sufficiently strong ferromagnetic interaction, we observe the emergence of an asymmetric vortex-bright soliton as the ground state. We also numerically investigate stable moving solitons and binary collision between them. The present mean-field model is not Galilean invariant, and we use a Galilean-transformed model for generating the moving solitons. At low velocities, the head-on collision between two {\em in-phase} solitons results either in collapse or fusion of the soliton pair. On the other hand, in head-on collision, the two {\em out-of-phase} solitons strongly repel each other and trace back their trajectories before the actual collision. At low velocities, in a collision with an impact parameter, the {\em out-of-phase} solitons get deflected from their original trajectory like two rigid classical disks. These {\em out-of-phase solitons} behave like classical disks, and their collision dynamics is governed by classical laws of motion. However, at large velocities two SO-coupled spinor solitons, irrespective of phase difference, can pass through each other in a head-on collision like two quantum solitons.