论文标题
量子测量下进攻值的动力学的相图
Phase Diagram of the Dynamics of a Precessing Qubit under Quantum Measurement
论文作者
论文摘要
我们研究了通过在外部横向磁场下依次测量单个值进攻引起的相变。在投射量子测量下，可以将测量结果的概率分布精确地映射到一维ISING模型的热力学概率分布，该模型的耦合可以通过磁场从铁磁到反铁磁剂的变化。对于顺序量子测量的一般情况，我们开发了一种快速，精确的算法，以计算铁磁顺序和抗铁磁性的概率分布函数，并在测量强度和磁场强度跨越的参数空间中获得相图。映射到远程相互作用的ISING模型是在小测量强度的极限下获得的。全面计数统计方法用于了解相图，并与编织组特征的拓扑相变与拓扑相变。这项工作加深了对量子测量引起的相变的理解，并可能提供了一种表征和引导量子进化的新方法。
We study the phase transitions induced by sequentially measuring a single qubit precessing under an external transverse magnetic field. Under projective quantum measurement, the probability distribution of the measurement outcomes can be mapped exactly to the thermodynamic probability distribution of a one-dimensional Ising model, whose coupling can be varied by the magnetic field from ferromagnetic to anti-ferromagnetic. For the general case of sequential quantum measurement,we develop a fast and exact algorithm to calculate the probability distribution function of the ferromagnetic order and anti-ferromagnetic order, and a phase diagram is obtained in the parameter space spanned by the measurement strength and magnetic field strength. The mapping to a long-range interacting Ising model is obtained in the limit of small measurement strength. Full counting statistical approach is applied to understand the phase diagram, and to make connections with the topological phase transition that is characterized by the braid group. This work deepens the understanding of phase transitions induced by quantum measurement, and may provide a new method to characterize and steer the quantum evolution.
