Quantum Trajectories and Their Statistics for Remotely Entangled Quantum Bits
Quantum Trajectories and Their Statistics for Remotely Entangled Quantum Bits
复制标题
DOI：
10.1103/physrevx.6.041052
复制
发表时间：
2016-12-14
影响因子：
12.5
通讯作者：
Jordan, Andrew N.
中科院分区：
文献类型：
--
作者：
Chantasri, Areeya;Kimchi-Schwartz, Mollie E.;Jordan, Andrew N.
我们从实验和理论上研究了嵌入在空间分离微波腔中的联合监测传输子量子比特的量子轨道。使用近量子噪声限制的超导放大器和优化的设置，以减少腔之间的信号损耗，我们可以有效地跟踪测量引起的纠缠产生作为一个连续的过程，为单一实现的实验。transmon量子比特的量子轨迹自然地分裂成低纠缠和高纠缠类。发现了任何给定时间的并发分布，并且我们探索了状态空间中纠缠创建的动态。该分布在高并发极限处表现出一个尖锐的截止，定义了一个最大并发边界。量子比特的轨迹的最可能的路径也被调查，导致三个可能的路径，逐渐投影系统到两个偶数子空间和一个奇数子空间，符合“半奇偶”测量。我们还研究了各个轨迹到达最纠缠态的最可能时间，我们发现局部最大值有两个解，分别对应于低纠缠和高纠缠路径。理论预测与实验纠缠量子比特轨道数据显示出良好的一致性。
We experimentally and theoretically investigate the quantum trajectories of jointly monitored transmon qubits embedded in spatially separated microwave cavities. Using nearly quantum-noise-limited superconducting amplifiers and an optimized setup to reduce signal loss between cavities, we can efficiently track measurement-induced entanglement generation as a continuous process for single realizations of the experiment. The quantum trajectories of transmon qubits naturally split into low and high entanglement classes. The distribution of concurrence is found at any given time, and we explore the dynamics of entanglement creation in the state space. The distribution exhibits a sharp cutoff in the high concurrence limit, defining a maximal concurrence boundary. The most-likely paths of the qubits' trajectories are also investigated, resulting in three probable paths, gradually projecting the system to two even subspaces and an odd subspace, conforming to a "half-parity" measurement. We also investigate the most-likely time for the individual trajectories to reach their most entangled state, and we find that there are two solutions for the local maximum, corresponding to the low and high entanglement routes. The theoretical predictions show excellent agreement with the experimental entangled-qubit trajectory data.