Dynamical generation of dark solitons in spin-orbit-coupled Bose-Einstein condensates

TL;DR

This paper numerically explores how dark solitons can be generated and controlled in a spin-orbit-coupled Bose-Einstein condensate through dynamic phase transitions induced by varying Raman coupling.

Contribution

It demonstrates a method to generate and manipulate dark solitons in spin-orbit-coupled BECs via non-equilibrium dynamics during phase transitions.

Findings

Dark solitons are excited during phase sweeps from stripe to other phases.

The number and stability of dark solitons can be controlled by the driving parameters.

Different nonlinear excitations depend on the phase transition path.

Abstract

We numerically investigate the ground state, the Raman-driving dynamics and the nonlinear excitations of a realized spin-orbit-coupled Bose-Einstein condensate in a one-dimensional harmonic trap. Depending on the Raman coupling and the interatomic interactions, three ground-state phases are identified: stripe, plane wave and zero-momentum phases. A narrow parameter regime with coexistence of stripe and zero-momentum or plane wave phases in real space is found. Several sweep progresses across different phases by driving the Raman coupling linearly in time is simulated and the non-equilibrium dynamics of the system in these sweeps are studied. We find kinds of nonlinear excitations, with the particular dark solitons excited in the sweep from the stripe phase to the plane wave or zero-momentum phase within the trap. Moreover, the number and the stability of the dark solitons can be controlled in the driving, which provide a direct and easy way to generate dark solitons and study their dynamics and interaction properties.