Emergence of topological and strongly correlated ground states in trapped Rashba spin-orbit-coupled Bose gases

Abstract

We theoretically study an interacting few-body system of Rashba spin-orbit-coupled two-component Bose gases confined in a harmonic trapping potential. We solve the interacting Hamiltonian at large Rashba coupling strengths using an exact-diagonalization scheme, and obtain the ground-state phase diagram for a range of interatomic interactions and particle numbers. At small particle numbers, we observe that the bosons condense to an array of topological states with n + 1/2 quantum angular momentum vortex configurations, where n = 0,1,2,3, . . .. At large particle numbers, we observe two distinct regimes: at weaker-interaction strengths, we obtain ground states with topological and symmetry properties that are consistent with mean-field theory computations; at stronger-interaction strengths, we report the emergence of strongly correlated ground states.

Scattering and effective interactions of ultracold atoms with spin-orbit coupling

“…Therefore, it is apparent that we have /eff(i' ^ 0 = - (43) with By requiring that the zero-energy effective scattering amplitude /eff(i' -^ i) be equal to the realistic scattering amplitude, i.e.. fefíit' ^ 0 = fit' (45) with E, =0 and fit' <-i) given by Eq. (19), we obtain the following renormalization relation for systems with SO coupling in the limit kc -^ oo:…”

Spin–orbit-coupled Bose–Einstein-condensed atoms confined in annular potentials

“…In this case, the width of the annulus (the oscillator length a 0 ) provides an extra length scale, which is a fraction of R. For a narrow annulus (R a 0  ) one goes back to the problem of quasi-one-dimensional motion discussed above. When a R 0 » then the problem reduces to that of a harmonic trapping potential [28,33,36,39,40,44,[59][60][61] with a small 'hole' in the center of the trap. The most interesting case is thus the intermediate one when a R 0  .…”

“…Motivated by the above experiments, we investigate the lowest-energy states that appear in a spin-orbitcoupled Bose-Einstein-condensed cloud of atoms that is trapped in an annular potential, using the mean-field approximation. A lot of work has been done in homogeneous [26,27,[55][56][57][58] and in harmonically-trapped systems [28,33,36,39,40,44,[59][60][61]. In the presence of an annular potential, however, this problem becomes surprisingly challenging.…”

Evidence for correlated states in a cluster of bosons with Rashba spin-orbit coupling

“…To understand how strong spin-orbit coupling can help the bosons to suppress interaction energy, we study a cluster of bosons with the Rashba spin-orbit coupling in a two-dimensional disk of radius R with a hard wall boundary condition, while earlier works has focused on two-dimensional harmonic trap confinement [40,[52][53][54][55]. In this case, the single particle eigen-wave-functions with eigenenergies E nm have the generic form…”