Maximum-likelihood estimation of the density matrix
Maximum-likelihood estimation of the density matrix
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DOI：
10.1103/physreva.61.010304
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发表时间：
2000-01-01
影响因子：
2.9
通讯作者：
Sacchi, MF
中科院分区：
文献类型：
--
作者：
Banaszek, K;D'Ariano, GM;Sacchi, MF
我们提出了一种基于最大似然法的量子态估计的通用技术。这种方法根据对相同制备的系统副本执行的一系列测量来提供密度矩阵的正定估计。该方法用途广泛，可应用于多模辐射场以及自旋系统。物理约束的结合在最大似然策略中是自然的，导致统计误差的大幅减少。该方法的数值实现基于正定埃尔米特矩阵的高斯分解的特定形式。
We present a universal technique for quantum-state estimation based on the maximum-likelihood method. This approach provides a positive-definite estimate for the density matrix from a sequence of measurements performed on identically prepared copies of the system. The method is versatile and can be applied to multimode radiation fields as well as to spin systems. The incorporation of physical constraints, which is natural in the maximum-likelihood strategy, leads to a substantial reduction of statistical errors. Numerical implementation of the method is based on a particular form of the Gauss decomposition for positive-definite Hermitian matrices.