Van Regemortel Mathias, Cian Ze-Pei, Seif Alireza, Dehghani Hossein, Hafezi Mohammad
Joint Quantum Institute, College Park, 20742 Maryland, USA and The Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, 20742 Maryland, USA.
Phys Rev Lett. 2021 Mar 26;126(12):123604. doi: 10.1103/PhysRevLett.126.123604.
Dissipation generally leads to the decoherence of a quantum state. In contrast, numerous recent proposals have illustrated that dissipation can also be tailored to stabilize many-body entangled quantum states. While the focus of these works has been primarily on engineering the nonequilibrium steady state, we investigate the buildup of entanglement in the quantum trajectories. Specifically, we analyze the competition between two different dissipation channels arising from two incompatible continuous monitoring protocols. The first protocol locks the phase of neighboring sites upon registering a quantum jump, thereby generating a long-range entanglement through the system, while the second destroys the coherence via a dephasing mechanism. By studying the unraveling of stochastic quantum trajectories associated with the continuous monitoring protocols, we present a transition for the scaling of the averaged trajectory entanglement entropies, from critical scaling to area-law behavior. Our work provides an alternative perspective on the measurement-induced phase transition: the measurement can be viewed as monitoring and registering quantum jumps, offering an intriguing extension of these phase transitions through the long-established realm of quantum optics.
耗散通常会导致量子态的退相干。相比之下，最近众多的提议表明，耗散也可以被调控以稳定多体纠缠量子态。虽然这些工作主要关注非平衡稳态的工程设计，但我们研究了量子轨迹中纠缠的积累。具体而言，我们分析了由两种不兼容的连续监测协议产生的两种不同耗散通道之间的竞争。第一种协议在记录到量子跃迁时锁定相邻位点的相位，从而在整个系统中产生长程纠缠，而第二种协议则通过退相机制破坏相干性。通过研究与连续监测协议相关的随机量子轨迹的展开，我们展示了平均轨迹纠缠熵标度的转变，从临界标度转变为面积律行为。我们的工作为测量诱导的相变提供了一个新的视角：测量可以被视为对量子跃迁的监测和记录，通过久已确立的量子光学领域为这些相变提供了一个有趣的扩展。
