论文标题
多体量子ZENO效应和测量诱导的亚缩度转变
Many-Body Quantum Zeno Effect and Measurement-Induced Subradiance Transition
论文作者
论文摘要
众所周知，通过反复测量量子系统，可以将其动力学完全冻结到定义明确的状态，这是量子Zeno效应的标志。在这里，我们表明，对于在竞争的统一进化和可变强度测量下进化的多体系统，ZENO效应的开始采用了尖锐的相变的形式。使用将横向磁化的量子链连续监测为范式示例，我们表明，对于弱测量值，统一动力学产生的纠缠仍然受到保护，并且实际上通过监测来增强，而仅在一定的阈值中，系统才能急剧地将系统带入一个未经正确的Zeno状态。我们表明，这种过渡是平均动力学的看不见的，但是在随机测量过程的罕见波动中编码，我们证明，这是由非热汉密尔顿人完全捕获的，该非热汉密尔顿人以想象中的横向横向场中的量子ising模型的形式。我们基于非亚米特汉密尔顿人的费物化提供了分析结果，以支持我们的精确数值计算。
It is well known that by repeatedly measuring a quantum system it is possible to completely freeze its dynamics into a well defined state, a signature of the quantum Zeno effect. Here we show that for a many-body system evolving under competing unitary evolution and variable-strength measurements the onset of the Zeno effect takes the form of a sharp phase transition. Using the Quantum Ising chain with continuous monitoring of the transverse magnetization as paradigmatic example we show that for weak measurements the entanglement produced by the unitary dynamics remains protected, and actually enhanced by the monitoring, while only above a certain threshold the system is sharply brought into an uncorrelated Zeno state. We show that this transition is invisible to the average dynamics, but encoded in the rare fluctuations of the stochastic measurement process, which we show to be perfectly captured by a non-Hermitian Hamiltonian which takes the form of a Quantum Ising model in an imaginary valued transverse field. We provide analytical results based on the fermionization of the non-Hermitian Hamiltonian in supports of our exact numerical calculations.
