Optical-lattice-assisted magnetic phase transition in a spin-orbit-coupled Bose-Einstein condensate

TL;DR

This study explores how a one-dimensional optical lattice influences magnetic phase transitions in a spin-orbit-coupled Bose-Einstein condensate, revealing conditions for observable transitions and density modulations.

Contribution

It demonstrates that a periodic optical lattice can induce magnetic phase transitions in a spin-orbit-coupled Bose gas, especially near the roton momentum, with potential for experimental observation.

Findings

Magnetic phase transition can be triggered by increasing lattice strength.

Transition is enhanced when the lattice wave vector is close to the roton momentum.

The system shows significant density fringe contrast at the transition.

Abstract

We investigate the effect of a periodic potential generated by a one-dimensional optical lattice on the magnetic properties of an $S=1/2$ spin-orbit-coupled Bose gas. By increasing the lattice strength one can achieve a magnetic phase transition between a polarized and an unpolarized Bloch wave phase, characterized by a significant enhancement of the contrast of the density fringes. If the wave vector of the periodic potential is chosen close to the roton momentum, the transition could take place at very small lattice intensities, revealing the strong enhancement of the response of the system to a weak density perturbation. By solving the Gross-Pitaevskii equation in the presence of a three-dimensional trapping potential, we shed light on the possibility of observing the magnetic phase transition in currently available experimental conditions.