Study of unconventional superfluid phases and the phase dynamics in spin-orbit coupled bose system

TL;DR

This paper investigates the phase behavior and dynamics of spin-orbit coupled two-component ultracold bosons, revealing transitions from homogeneous superfluid to twisted and stripe-ordered phases, and analyzing collective excitations.

Contribution

It provides a detailed analysis of phase evolution, ordering, and collective modes in spin-orbit coupled bosonic systems using inhomogeneous mean-field theory.

Findings

Homogeneous superfluid phase at high hopping

Twisted superfluid phase with increasing spin-orbit coupling

Stripe magnetic ordering at large spin-orbit coupling

Abstract

We study the phase distribution and its dynamics in spin-orbit coupled two component ultracold Bosons for finite size system. Using an inhomogeneous meanfield analysis we demonstrate how phase distribution evolves as we tune the spin-orbit coupling $\gamma$ and $t$, the spin-independent hopping. For $t>>\gamma$ we find the homogeneous superfluid phase. As we increase $\gamma$, differences in the phases of the order parameter grows leading to twisted superfluid phase. For $t \sim \gamma$ competing orderings in the phase distribution is observed. At large $\gamma$ limit a Ferro-Magnetic stripe ordering appears along the diagonal. We explain that this is due to the frustration bought in by the spin-orbit interaction. Isolated vortex formation is also shown to appear. We also investigate the possible collective modes. In deep superfluid regime we derive the equation of motion for the phases following a semi-classical approximation. Imaginary frequencies indicating the damped modes are seen to appear and the dynamics of lowest normal modes are discussed.