量子芝诺效应远距离间接测量的不可能性

The quantum Zeno and anti-Zeno effects with strong system-environment coupling

The fact that repeated projective measurements can slow down (the Zeno effect) or speed up (the anti-Zeno effect) quantum evolution is well-known. However, to date, studies of these effects focus on quantum systems that are weakly interacting with their environment. In this paper, we investigate what happens to a quantum system under the action of repeated measurements if the quantum system is strongly interacting with its environment. We consider as the quantum system a single two-level system coupled strongly to a collection of harmonic oscillators. A so-called polaron transformation is then…

Interaction-free measurements by quantum Zeno stabilisation of ultracold atoms

Quantum mechanics predicts that our physical reality is influenced by events that can potentially happen but factually do not occur. Interaction-free measurements (IFMs) exploit this counterintuitive influence to detect the presence of an object without requiring any interaction with it. Here we propose and realize an IFM concept based on an unstable many-particle system. In our experiments, we employ an ultracold gas in an unstable spin configuration which can undergo a rapid decay. The object - realized by a laser beam - prevents this decay due to the indirect quantum Zeno effect and thus, i…

Coalescence of non-Markovian dissipation, quantum Zeno effect and non-Hermitian physics, in a simple realistic quantum system

Diagonalization of the effective Hamiltonian describing an open quantum system is the usual method of tracking its exceptional points. Although, such a method is successful for tracking EPs in Markovian systems, it may be problematic in non-Markovian systems where a closed expression of the effective Hamiltonian describing the open system may not exist. In this work we provide an alternative method of tracking EPs in open quantum systems, using an experimentally measurable quantity, namely the effective decay rate of a qubit. The quantum system under consideration consists of two non-identical…

调制器辅助的量子电池能量传输的泽诺控制

Modulator-Assisted Zeno Control of Energy Transfer in Quantum Batteries

本文提出一种调制器辅助的量子电池协议，通过局部单位元操作动态重塑有效哈密顿量，实现能量传输的开关控制，并在多体系统中展示其扩展性。

多种形式的芝诺效应带来的Grover加速

Grover Speedup from Many Forms of the Zeno Effect

本文证明测量、退相干及激发态衰变等多种芝诺效应形式均可实现最优Grover型量子加速，并将相关算法归纳为相位踢击、退相测量和振幅破坏三个族，为模拟量子计算新范式提供可能。

Continuous quantum error detection and suppression with pairwise local interactions

Performing measurements for high-weight operators has been a practical problem in quantum computation, especially for quantum codes in the stabilizer formalism. The conventional procedure of measuring a high-weight operator requires multiple pairwise unitary operations, which can be slow and prone to errors. We provide an alternative method to passively detect the value of a high-weight operator using only two-local interactions and single-qubit continuous measurements. This approach involves joint interactions between the system and continuously-monitored ancillary qubits. The measurement out…

量子芝诺效应的一般测量

Quantum Zeno effect by general measurements

据预测，对不稳定的量子态的频繁重复测量可能会改变该态的衰变速率。这被称为量子芝诺效应（QZE）或反芝诺效应（AZE），这取决于衰变是被抑制还是被增强。在传统的QZE和AZE理论中，测量的影响被简单地描述为投影公设，假设每个测量都是瞬时的和理想的。然而，实际测量不是瞬时的和理想的。对于QZE和AZE通过这样的一般测量，有趣的和令人惊讶的功能，最近被发现，我们在这篇文章中审查。这些结果是基于量子测量理论，并简要地作了评述。作为一个典型的模型，我们考虑了一个连续的测量激发原子的衰变的光电探测器，检测从原子衰变时发出的光子。这种测量是一种间接的负结果测量，因此强调了QZE和AZE的好奇心。它示出的形状因子重整化作为测量的反作用，通过它的衰减动力学被修改。在平坦响应的特殊情况下，探测器以相同的响应时间响应每个光子模式，传统理论的结果被定性地再现。然而，在探测器仅对有限光子模式作出响应的一般情况下，出现了巨大的差异。例如，与传统理论的预测相反，QZE或AZE甚至可能发生在完全遵循指数衰减定律的状态。我们还讨论了与腔量子电动力学的关系。

由POVM生成的量子轨迹无需随机微分方程

POVM generated quantum trajectories without stochastic differential equations

本文提出了一种无需随机微分方程的方法，通过量子力学直接推导出由POVM生成的量子轨迹的渐进行为，揭示了轨迹趋于系统本征态或由退化本征态张成的密度矩阵。

开放量子系统中的稳定双极化子

Stable bipolarons in open quantum systems

该研究结合非马尔可夫纯态层级法、马尔可夫量子跳跃法与投影纯化密度矩阵重整化群，研究耗散环境下Hubbard-Holstein模型的输运与双极化子稳定性，发现耗散使双极化子局域化但结合能不受影响，为设计高$T_\mathrm{C}$超导材料提供启示。