Upper bound of the accessible information and lower bound of the Bayes cost in quantum signal-detection processes
Masashi Ban, Masao Osaki, Osamu Hirota · Physical Review A · 1996
Upper bound of the accessible information and lower bound of the Bayes cost in quantum detection processes for Gaussian state signals under the influence of thermal noise are derived by means of the superoperator representation of quantum states. It is shown that the upper and lower bounds are obtained by replacing the parameters of the signal quantum state with the renormalized parameters including the thermal noise effects in the accessible information and the minimum value of the Bayes cost in quantum detection processes in the absence of thermal noise. Analytic expressions of the upper and lower bounds are given for several quantum state signals. \textcopyright{} 1996 The American Physical Society.