Gauge-potential-induced rotation of spin-orbit-coupled Bose-Einstein condensates

Abstract

We demonstrate that a spin-orbit-coupled Bose-Einstein condensate can be effectively rotated by adding a real magnetic field to inputting gauge angular momentum, which is distinctly different from the traditional ways of rotation by stirring or Raman laser dressing to inputting canonical angular momentum. The gauge angular momentum is accompanied by the spontaneous generation of equal and opposite canonical angular momentum in the ground states, and it leads to the nucleation of quantized vortices. We explain this by indicating that the effective rotation with the vortex nucleation results from the effective magnetic flux induced by the gauge potential, which is essentially different from the previous scheme of creating vortices by synthetic magnetic fields. In the weakly interacting regime, symmetrically placed domains separated by vortex lines as well as half-integer giant vortices are discovered. With relatively strong interatomic interaction, we predict a structure of coaxially arranged annular vortex arrays, which is in stark contrast to the familiar Abrikosov vortex lattice. The developed way of rotation may be extended to a more general gauge system.

Bose–Einstein condensates in rotating ring-shaped lattices: a multimode model

“…In particular, the first experimental realization of an optical lattice that allowed for the generation of large tunable homogeneous artificial magnetic fields was demonstrated in [50] with the realization of the Hofstadter Hamiltonian with ultracold atoms. The studies of synthetic gauge potentials have also boosted theoretical investigations on condensates with coupled degrees of freedom providing a renewed fertile ground for research [51,52].…”

Vortex chains induced by anisotropic spin–orbit coupling and magnetic field in spin-2 Bose-Einstein condensates

“…[25] In physics, rotation can be characterized by nonzero canonical angular momentum ⟨L c z ⟩ = 𝛹 † (𝑟 × p)𝛹 d𝑟. [26][27][28][29] And vortices are generated in response to the canonical angular momentum. [28,29] The common ways to rotate the condensates, including stirring the condensate [30] or rotating the anisotropic trap, [31] could introduce canonical angular momentum.…”

“…[26][27][28][29] And vortices are generated in response to the canonical angular momentum. [28,29] The common ways to rotate the condensates, including stirring the condensate [30] or rotating the anisotropic trap, [31] could introduce canonical angular momentum. However, with the help of gauge field and magnetic field, nonzero canonical angular momentum can also be generated.…”

“…However, with the help of gauge field and magnetic field, nonzero canonical angular momentum can also be generated. [28] Recent investigations on artificial gauge field, i.e., spinorbit coupling (SOC) techniques [32][33][34] in spinor BECs have attracted tremendous interest in systematically studying the novel vortex structures hosted by spinor BECs. For example, Xu et al have found that Rashba-type SOC could trigger a one-dimensional (1D) vortex chain in spin-1/2 BECs.…”

“…[39] Accompanied by the Ioffe-Pritchard (IP) magnetic field, Dresselhaus-type SOC could trigger vortex lattices in spin-1/2 BECs without external rotation. [28] Various nontrivial excitations, i.e., strip phase and vortex-ring phase, have been investigated with the combined effects of rotation, magnetic field or isotropic SOC in the low-spin systems. [40,41] However, the exotic vortex configurations in the ferromagnetic phase, anti-ferromagnetic phase or the cyclic phase of the spin-2 BECs system remain unclear.…”