论文标题
激子 - 波利顿冷凝物中的非平衡Landau-Zener隧道
Nonequilibrium Landau-Zener Tunneling in Exciton-Polariton Condensates
论文作者
论文摘要
对于通过线性依赖时间依赖性的驱动的连贯的量子机械两级系统，Landau-Zener模型已作为量子动力学的教科书模型多数十年。一个特别有趣的问题是，是否可以扩展该框架以捕获具有相等和耗散动态的量子系统的固有非平衡性质。在这项工作中，考虑到驱动的驱动性的pitaevskii方程与储层的速率方程式，我们有动力研究极性凝结物的Landau-Zenner问题。使用两模式方法，我们发现储层的波动可以被视为常数，并且相对阶段起着非常重要的作用。我们获得的耗散Landau-Zener模型的演变表明其绝热过程与封闭系统截然不同，因为储层的波动具有峰值，并导致冷凝水的阻尼。我们将水库的波动代替哈密顿式的波动，并获得有效的两级模型。还讨论了哈密顿量在相空间中的运动，并直接对应于抽水速率。在相空间中的曲线也可以研究带结构的不稳定性，当泵送速率远远超出阈值时，布里渊区中间可能有两个环。
For a coherent quantum mechanical two-level system driven with a linearly time-dependent detuning, the Landau-Zener model has served over decades as a textbook model of quantum dynamics. A particularly intriguing question is whether that framework can be extended to capture an intrinsical nonequilibrium nature for a quantum system with coherent and dissipative dynamics occurring on an equal footing. In this work, we are motivated to investigate the Landau-Zenner problem of polariton condensates in a periodic potential under nonresonant pumping, considering driven-dissipative Gross-Pitaevskii equations coupled to the rate equation of a reservoir. Using a two-mode approach, we find fluctuation of the reservoir can be considered as a constant and the relative phase plays a very important role. The evolution of the dissipative Landau-Zener model we obtain presents its adiabatic process very different from the closed system because the fluctuation of the reservoir has a peak and leads to the damping of the condensates. We substitute the fluctuation of the reservoir to Hamiltonian and get an effective two-level model. The motion of Hamiltonian in phase space is also discussed and is directly corresponding to the pumping rate. The instability of the band structure can also be studied by the curvatures in phase space and there may be two loops in the middle of the Brillouin zone when the pumping rate is far beyond the threshold.
