Approach for making visible and stable stripes in a spin-orbit-coupled Bose-Einstein superfluid

TL;DR

This paper proposes a method to produce high-contrast, stable striped phases in spin-orbit-coupled Bose-Einstein condensates, enhancing experimental detection and understanding of supersolid-like states.

Contribution

It introduces a space-separated bilayer approach to stabilize and enhance stripe visibility, confirmed by 3D Gross-Pitaevskii simulations, and explores pulse effects on stripe properties.

Findings

High-contrast striped configurations achieved

Bilayer separation reduces interspecies interaction

Pulse techniques modulate stripe wavelength and coherence

Abstract

The striped phase exhibited by a spin-$1/2$ Bose-Einstein condensate with spin-orbit coupling is characterized by the spontaneous breaking of two continuous symmetries: gauge and translational symmetry. This is a peculiar feature of supersolids and is the consequence of interaction effects. We propose an approach to produce striped configurations with high-contrast fringes, making their experimental detection in atomic gases a realistic perspective. Our approach, whose efficiency is directly confirmed by three-dimensional Gross-Pitaevskii simulations, is based on the space separation of the two spin components into a two-dimensional bilayer configuration, causing the reduction of the effective interspecies interaction and the increase of the stability of the striped phase. We also explore the effect of a $\pi/2$ Bragg pulse, causing the increase of the fringe wavelength, and of a $\pi/2$ rf pulse, revealing the coherent nature of the order parameter in the spin channel.