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arXiv 1104.4252math.STstat.TH
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基于斜信息的近似量子Cramér-Rao界

An approximate quantum Cramér--Rao bound based on skew information

Alessandra Luati

摘要:

导出了混合态量子系统中Wigner-Yanase偏斜信息的封闭表达式。结果表明,存在混合系数的极限值,使得Wigner-Yanase信息等于Helstrom信息。后者构成了经典的预期Fisher信息的上界,因此逆Wigner-Yanase信息提供了感兴趣的参数的无偏估计的方差的近似下界。近似Helstrom的锐界的优点在于Wigner-Yanase信息计算简单,而Helstrom信息的可行表达式通常非常困难。实际上,后者需要求解一个隐式二阶矩阵微分方程,而前者只需要标量微分。

英文摘要:

A closed-form expression for Wigner-Yanase skew information in mixed-state quantum systems is derived. It is shown that limit values of the mixing coefficients exist such that Wigner-Yanase information is equal to Helstrom information. The latter constitutes an upper bound for the classical expected Fisher information, hence the inverse Wigner-Yanase information provides an approximate lower bound to the variance of an unbiased estimator of the parameter of interest. The advantage of approximating Helstrom's sharp bound lies in the fact that Wigner-Yanase information is straightforward to compute, while it is often very difficult to obtain a feasible expression for Helstrom information. In fact, the latter requires the solution of an implicit second order matrix differential equation, while the former requires just scalar differentiation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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