AI 中文总结
该研究建立了测量诱导衰减的通用谱判据，通过分析Liouvillian谱隙与测量频率的关系区分量子芝诺和反芝诺响应，并在两类量子比特模型中验证了该判据，为操控量子系统的相关效应提供了实用方法。
AI 中文摘要
我们开发了一个通用框架，用于表征演化量子系统对重复量子测量的响应。将每个演化-测量循环建模为有效Liouvillian生成元诱导的量子信道，我们发现Liouvillian谱隙决定了测量诱导的衰减率。我们分析了谱隙如何响应测量频率，定义量子芝诺响应为谱隙随测量频率增加而减小，反芝诺响应则相反。我们针对离散时间和连续时间量子测量示例说明了该判据。在一个可精确求解的离散时间量子比特模型中，例外点的谱合并或谱交叉标志着芝诺与反芝诺响应之间的转变，可通过存活概率的长时间衰变包络在实验上区分。在连续时间超导量子比特缺陷模型中，同样的转变表现为谱隙的平滑极值。我们的结果建立了测量诱导衰减的通用谱判据，为在一般量子系统中识别和操控这些效应提供了实用途径。
英文摘要
We develop a general framework for characterizing the response of an evolving quantum system to repetitive quantum measurements. Modeling each evolution-measurement cycle as a quantum channel induced by an effective Liouvillian generator, we find that the Liouvillian spectral gap determines the measurement-induced decay rate. We analyze how the spectral gap responds to the measurement frequency, and define a quantum Zeno response as a decrease in the gap with increasing measurement frequency, and an anti-Zeno response as the opposite. We illustrate this criterion for both discrete-time and continuous-time quantum measurements. In an exactly solvable discrete-time qubit model, the exceptional-point spectral coalescence or spectral crossings mark the transition between Zeno and anti-Zeno responses, which can be experimentally distinguished from the long-time decay envelope of the survival probability. In a continuous-time superconducting-qubit defect model, the same transition manifests as smooth extrema of the spectral gap. Our results establish a universal spectral criterion for measurement-induced decay, offering a practical route to identify and manipulate these effects in generic quantum systems.
Comments5 pages, 3 figures
