2015/05/25 by Ting Fung Jeffrey Poon, Jeffrey Ting Fung Poon, Xiong-Jun Liu
Physics and Astronomy · #Bose–Einstein condensate #Boson #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Degenerate energy levels #Ground state #Non-equilibrium thermodynamics #Perturbation (astronomy) #Phase transition #Physics #Quantum #Quantum electrodynamics #Quantum many-body systems #Quantum mechanics #Quantum phase transition #Strong Light-Matter Interactions #cond-mat.mes-hall #cond-mat.quant-gas #quant-ph
paper · pdf · doi:10.1103/physreva.93.063420
published as Phys. Rev. A 93, 063420 (2016) · 9 pages, 4 figures, plus supplementary material
arxiv created 2015/05/25 · openalex publication_date 2016/06/21 · arxiv updated 2016/06/22 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Spin-orbit-coupled bosons can exhibit rich equilibrium phases at low temperature and in the presence of particle-particle interactions. In the case with a 1D synthetic spin-orbit interaction, it has been observed that the ground state of a Bose gas can be a normal phase, stripe phase, or magnetized phase in different parameter regimes. The magnetized states are doubly degenerate and consist of a many-particle two-state system. In this work, we investigate the nonequilibrium quantum dynamics by switching on a simple one-dimensional optical lattice potential as external perturbation to induce resonant couplings between the magnetized phases, and predict a quantum spin dynamics which cannot be obtained in the single-particle systems. In particular, due to particle-particle interactions, the transition of the Bose condensate from one magnetized phase to the other is forbidden when the external perturbation strength is less than a critical value, and a full transition can occur only when the perturbation exceeds such critical strength. This phenomenon manifests itself a dynamical phase transition, with the order parameter defined by the time-averaged magnetization over an oscillation period, and the critical point behavior being exactly solvable. The thermal fluctuations are also considered in detail. From numerical simulations and exact analytic studies we show that the predicted many-body effects can be well observed with the current experiments.