TY - JOUR
T1 - N-body-extended channel estimation for low-noise parameters
AU - Hotta, M.
AU - Karasawa, T.
AU - Ozawa, M.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 2006/11/17
Y1 - 2006/11/17
N2 - The notion of low-noise channels was recently proposed and analysed in detail in order to describe noise-processes driven by the environment (Hotta M, Karasawa T and Ozawa M 2005 Phys. Rev. A 72 052334). An estimation theory of low-noise parameters of channels has also been developed. In this paper, we address the low-noise parameter estimation problem for the N-body extension of the dissipative low-noise channels. We perturbatively calculate the Fisher information of the output states in order to evaluate the lower bound of the mean-square error of the parameter estimation. We show that the maximum of the Fisher information over all input states can be attained by a factorized input state in the leading order of the low-noise parameter. Thus, to achieve optimal estimation, it is not necessary for there to be entanglement of the N subsystems, as long as the true low-noise parameter is sufficiently small and the channel is properly dissipative.
AB - The notion of low-noise channels was recently proposed and analysed in detail in order to describe noise-processes driven by the environment (Hotta M, Karasawa T and Ozawa M 2005 Phys. Rev. A 72 052334). An estimation theory of low-noise parameters of channels has also been developed. In this paper, we address the low-noise parameter estimation problem for the N-body extension of the dissipative low-noise channels. We perturbatively calculate the Fisher information of the output states in order to evaluate the lower bound of the mean-square error of the parameter estimation. We show that the maximum of the Fisher information over all input states can be attained by a factorized input state in the leading order of the low-noise parameter. Thus, to achieve optimal estimation, it is not necessary for there to be entanglement of the N subsystems, as long as the true low-noise parameter is sufficiently small and the channel is properly dissipative.
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U2 - 10.1088/0305-4470/39/46/015
DO - 10.1088/0305-4470/39/46/015
M3 - Article
AN - SCOPUS:33947218428
VL - 39
SP - 14465
EP - 14470
JO - Journal of Physics A: Mathematical and Theoretical
JF - Journal of Physics A: Mathematical and Theoretical
SN - 1751-8113
IS - 46
M1 - 015
ER -