Ground-state phases of ultracold bosons with Rashba-Dresselhaus spin-orbit coupling

TL;DR

This paper investigates the ground-state phases of three-dimensional ultracold bosons with Rashba-Dresselhaus spin-orbit coupling, revealing complex phase diagrams with three distinct phases through an exact two-boson t-matrix approach.

Contribution

It introduces an exact summation of ladder diagrams for the two-boson t-matrix and uses it to analyze ground-state phases, improving upon mean-field predictions especially at large scattering lengths and strong spin-orbit coupling.

Findings

Identified three phases: plane-wave, striped, and unstable.

Found significant differences from mean-field results at large scattering lengths.

Revealed richer phase structures with the t-matrix approach.

Abstract

We study ultracold bosons in three dimensions with an anisotropic Rashba-Dresselhaus spin-orbit coupling. We first carry out the exact summation of ladder diagrams for the two-boson t-matrix at zero energy. Then, with the t-matrix as the effective interaction, we find the ground-state phase diagrams of bosons in mean field as a function of the spin-orbit coupling, the anisotropy, and the scattering lengths between particles in the same and in different pseudospin states. The resulting phase diagrams have much richer structures than those obtained using mean-field couplings, exhibiting three different phases: a plane-wave condensate, a striped condensate, and an unstable phase. The differences between the present approach using the t-matrix compared to using mean-field couplings is significant for large scattering lengths, large spin-orbit-coupling strength, or small anisotropy.