标题： 过程重构：通过最大似然从非物理图映射到物理图 显示英文标题

标题： Process reconstruction: From unphysical to physical maps via maximum likelihood

摘要： 我们证明，最大似然方法（MML）为我们提供了一种从不完整的测量数据中重建量子通道的高效方案。 根据构造，此方案总是得到完全正的通道估计。 利用这一特性，我们使用MML推导出非物理操作的物理近似。 特别是，我们分析了通用NOT门的最佳近似以及量子非线性偏振旋转的物理近似。 显示英文摘要

摘要： We show that the method of maximum likelihood (MML) provides us with an efficient scheme for reconstruction of quantum channels from incomplete measurement data. By construction this scheme always results in estimations of channels that are completely positive. Using this property we use the MML for a derivation of physical approximations of un-physical operations. In particular, we analyze the optimal approximation of the universal NOT gate as well as a physical approximation of a quantum nonlinear polarization rotation.