Spin Josephson effects of spin-orbit-coupled Bose-Einstein condensates in a non-Hermitian double well

• URL: http://arxiv.org/abs/2208.13198v1
• Date: Sun, 28 Aug 2022 10:50:46 GMT
• Title: Spin Josephson effects of spin-orbit-coupled Bose-Einstein condensates in a non-Hermitian double well
• Authors: Jia Tang, Zhou Hu, Zhao-Yun Zeng, Jinpeng Xiao, Lei Li, Yajiang Chen, Ai-Xi Chen, and Xiaobing Luo
• Abstract summary: We investigate the spin and tunneling dynamics of a Bose-Einstein condensate in a periodically driven non-Hermitian double-well potential. The results deepen the understanding of non-Hermitian physics and could be useful for engineering a variety of devices for spintronics.
• Score: 7.386723982670554
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In this paper, we investigate the spin and tunneling dynamics of a spin-orbit-coupled noninteracting Bose-Einstein condensate in a periodically driven non-Hermitian double-well potential. Under high-frequency driving, we obtain the effective time-averaged Hamiltonian by using the standard time-averaging method, and analytically calculate the Floquet quasienergies, revealing that the parity-time (PT)-breaking phase transition appears even for arbitrarily small non-Hermitian parameters when the spin-orbit coupling strength takes half-integer value, irrespective of the values of other parameters used. When the system is PT-symmetric with balanced gain and loss, we find numerically and analytically that in the broken PT-symmetric regions, there will exist the net spin current together with a vanishing atomic current, if we drop the contribution of the exponential growth of the norm to the current behaviors. When the system is non-PT-symmetric, though the quasienergies are partial complex, a stable net spin current can be generated by controlling the periodic driving field, which is accompanied by a spatial localization of the condensate in the well with gain. The results deepen the understanding of non-Hermitian physics and could be useful for engineering a variety of devices for spintronics.

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