Observing a topological transition in weak-measurement-induced geometric phases
Observing a topological transition in weak-measurement-induced geometric phases
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DOI：
10.1103/physrevresearch.4.023179
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发表时间：
2022-06-03
影响因子：
4.2
通讯作者：
Murch, Kater
中科院分区：
文献类型：
--
作者：
Wang, Yunzhao;Snizhko, Kyrylo;Murch, Kater
测量在量子系统的控制中起着至关重要的作用。除了与投影测量有关的初始化和读出之外，弱测量（特别是通过它们对系统的反向作用）可以实现各种级别的相干控制。后者的范围从观察量子轨迹到状态拖动和转向。此外，就像量子态的绝热演化会导致Berry相位一样，连续弱测量也会导致路径相关的几何相位。在这里，我们测量的几何相位引起的序列的弱测量，并证明了拓扑结构的几何相位的测量强度控制的转变。弱测量诱导量子动力学和拓扑跃迁之间的这种联系揭示了量子系统基于测量的操纵中微妙的拓扑特征。我们的协议可以针对操作类别（例如，编织），其本质上是拓扑的。此外，我们的结果为多体拓扑状态的测量支持的量子控制开辟了新的视野。
Measurement plays a quintessential role in the control of quantum systems. Beyond initialization and readout which pertain to projective measurements, weak measurements, in particular through their back action on the system, may enable various levels of coherent control. The latter ranges from observing quantum trajectories to state dragging and steering. Furthermore, just like the adiabatic evolution of quantum states that is known to induce the Berry phase, sequential weak measurements may lead to path-dependent geometric phases. Here we measure the geometric phases induced by sequences of weak measurements and demonstrate a topological transition in the geometric phase controlled by measurement strength. This connection between weak measurement-induced quantum dynamics and topological transitions reveals subtle topological features in measurement-based manipulation of quantum systems. Our protocol could be implemented for classes of operations (e.g., braiding) that are topological in nature. Furthermore, our results open new horizons for measurement-enabled quantum control of many-body topological states.