The synthetic gauge field and exotic vortex phase with spin-orbital-angular-momentum coupling

TL;DR

This paper proposes generating synthetic gauge fields in spinor Bose-Einstein condensates with spin-orbital-angular-momentum coupling, revealing exotic vortex states and phase transitions driven by light-induced synthetic magnetic fields.

Contribution

It introduces a method to create and analyze exotic vortex phases with controllable orbital angular momenta in ultracold atoms using combined laser fields.

Findings

Emergence of exotic vortex states with controllable orbital angular momentum.

Observation of phase transitions breaking rotational symmetry.

Density distributions characterized by synthetic magnetic fields.

Abstract

Ultracold atoms endowed with tunable spin-orbital-angular-momentum coupling (SOAMC) represent a promising avenue for delving into exotic quantum phenomena. Building on recent experimental advancements, we propose the generation of synthetic gauge fields ,and by including exotic vortex phases within spinor Bose-Einstein condensates, employing a combination of a running wave and Laguerre-Gaussian laser fields. We investigate the ground-state characteristics of the SOAMC condensate, revealing the emergence of exotic vortex states with controllable orbital angular momenta. It is shown that the interplay of the SOAMC and conventional spin-linear-momentum coupling induced by the running wave beam leads to the formation of a vortex state exhibiting a phase stripe hosting single multiply quantized singularity. The phase of the ground state will undergo the phase transition corresponding to the breaking of rotational symmetry while preserving the mirror symmetry. Importantly, the observed density distribution of the ground-state wavefunction, exhibiting broken rotational symmetry, can be well characterized by the synthetic magnetic field generated through light interaction with the dressed spin state. Our findings pave the way for further exploration into the rotational properties of stable exotic vortices with higher orbital angular momenta against splitting in the presence of synthetic gauge fields in ultracold quantum gases.