The non-uniform distributions of the magnetic moment along the z direction with different radial trapping frequencies ω (ω = ω_x = ω_y, ω_z = 10ω) in ⁸⁷Rb condensate with a total atom number N = 1 × 10⁴ and dimensionless SO coupling strength κ = 2.0

Figure 9. The non-uniform distributions of the magnetic moment along the z direction with different radial trapping frequencies ω (ω = ω_x = ω_y, ω_z = 10ω) in ⁸⁷Rb condensate with a total atom number N = 1 × 10⁴ and dimensionless SO coupling strength κ = 2.0. The unit of the space coordinates is a_{\perp }=\sqrt{\hbar /M\omega }.

Abstract

We analytically and numerically investigate the ground state of spin–orbit coupled spin-1 Bose–Einstein condensates in an external parabolic potential. When the spin–orbit coupling is introduced, spatial displacement exists between the atom densities of components with different magnetic quantum numbers. The analytical calculations show this displacement reaches a maximum when the spin–orbit coupling strength is comparable with that of the trapping potential. As the spin–orbit coupling strength gets larger and larger, the spatial displacement decreases at a rate inversely proportional to the spin–orbit coupling strength. Correspondingly, periphery half-skyrmion textures arise; this displacement can be reflected by the non-uniform magnetic moment in the z direction. With the manipulation of the external trap, the local magnitude of the non-uniform magnetic moment can be increased evidently. This kind of increase of the local magnetic moment is also observed in the square vortex lattice phase of the condensate.