论文标题
测量引起的连续时间晶体
Measurement Induced Continuous Time Crystals
论文作者
论文摘要
强尺寸的测量通常将测得的有限维系统的动力学限制为ZENO子空间，在该子空间中，由于抑制了耗散项，随后的进化是单一的。在这里，由于强测量和热力学极限之间的竞争，我们在质量上显示了不同的行为，从而诱导了时间翻译对称断裂相变，从而导致连续的时间晶体。我们考虑一个自旋星模型，其中中央旋转经过强烈的连续测量，并在各种参数状态下符合系统的动态行为。我们表明，高于测量强度的临界值高于热力学大型辅助旋转的磁化会发展限制周期振荡。我们的结果还表明，为了诱导连续的时间翻译对称性破裂，不需要连贯的驱动。
Strong measurements usually restrict the dynamics of measured finite dimensional systems to the Zeno subspace, where subsequent evolution is unitary due to the suppression of dissipative terms. Here we show qualitatively different behaviour due to the competition between strong measurements and the thermodynamic limit, inducing a time-translation symmetry breaking phase transition resulting in a continuous time crystal. We consider a spin star model, where the central spin is subject to a strong continuous measurement, and qualify the dynamic behaviour of the system in various parameter regimes. We show that above a critical value of measurement strength, the magnetization of the thermodynamically large ancilla spins develops limit cycle oscillations. Our result also demonstrates that a coherent drive is not necessary in order to induce continuous time-translation symmetry breaking.
