Quantum Entanglement in a Spin-Orbit Coupled Bose–Einstein Condensate

Yixiao Huang, Ning-Ju Hui, Wanfang Liu +2 more

Abstract We study the spin-field and the spin-spin entanglement in the ground state of a spin-orbit coupled Bose–Einstein condensate. It is found that the spin-field and the spin-spin entanglement can be induced by the spin-orbit coupling. By mapping the system to the Dicke-like model, the system exhibits a quantum phase transition from a normal (spin balanced) phase to superradiant (spin polarized) phase. The Dicke-like phase transition can be captured by the spin-field and the spin-spin entanglement arising from the spin-orbit coupling. The spin-field and the spin-spin entanglement increase as the Raman coupling increases in the superradiant phase, while they decrease with the Raman coupling increasing in the normal phase. We also consider the effect of a finite detuning on these entanglement show that the presence of the detuning suppresses the spin-field and the spin-spin entanglement.

Ying-Ling Mao

Shizhong Zhang, Tin-Lun Ho

Chao Kong, Xiaobing Luo, Hao Chen +2 more

It has been demonstrated that the presence of chaos may lead to greater entanglement generation for some physical systems. Here, we find different effects of chaos on the spin-motion entanglement for a two-frequency driven Bose-Einstein condensate with spin-orbit coupling. We analytically and numerically demonstrate that classical chaos can assist or suppress entanglement generation, depending on the initial phase differences between two motional states, which can be manipulated by using the known phase-engineering method. The results could be significant in engineering nonlinear dynamics for quantum information processing with many-body entanglement.

Li-Xin Xia, Yiming Xie

Sh. Mardonov, M. Palmero, Michele Modugno +2 more

Interference of atomic Bose-Einstein condensates, observed in free expansion experiments, is a basic characteristic of their quantum nature. The ability to produce synthetic spin-orbit coupling in Bose-Einstein condensates has recently opened a new research field. Here we theoretically describe interference of two noninteracting spin-orbit coupled Bose-Einstein condensates in an external synthetic magnetic field. We demonstrate that the spin-orbit and the Zeeman couplings strongly influence the interference pattern determined by the angle between the spins of the condensates, as can be seen in time-of-flight experiments. We show that a quantum backflow, being a subtle feature of the interference, is, nevertheless, robust against the spin-orbit coupling and applied synthetic magnetic field.