论文标题
单Qubit收获量子层造影
Single-Qubit Reaped Quantum State Tomography
论文作者
论文摘要
量子状态断层扫描是确定未知状态的实验程序。它不仅对于验证量子信息的资源和处理器至关重要，而且在量子力学的基础上本身也很重要。对于大型系统而言，标准方法是难以捉摸的，因为要测量的可观察到数量众多以及数据后处理的指数复杂性。在这里，我们提出了一个新的量子状态层析成像方案，该方案只需要测量三个可观察力（共同作用于系统和指针），而不管系统的大小如何。该系统与单个值的“指针”耦合，并且系统的波函数被“收获”到系统测量时的指针上。随后，用于指针和经典后处理的标准两态层析成像用于重建系统的量子状态。我们还开发了一种有效且可扩展的最大似然算法，以从统计上不完整的数据中估算状态。
Quantum state tomography is the experimental procedure of determining an unknown state. It is not only essential for the verification of resources and processors of quantum information but is also important in its own right with regard to the foundation of quantum mechanics. Standard methods have been elusive for large systems because of the enormous number of observables to be measured and the exponential complexity of data post-processing. Here, we propose a new scheme of quantum state tomography that requires the measurement of only three observables (acting jointly on the system and pointer) regardless of the size of the system. The system is coupled to a "pointer" of single qubit, and the wavefunction of the system is "reaped" onto the pointer upon the measurement of the system. Subsequently, standard two-state tomography on the pointer and classical post-processing are used to reconstruct the quantum state of the system. We also developed an efficient and scalable iterative maximum likelihood algorithm to estimate states from statistically incomplete data.
