Optimally Displaced Threshold Detection for Discriminating Binary Coherent States Using Imperfect Devices

Because of the potential applications in quantum information processing tasks, discrimination binary coherent states using generalized Kennedy receiver with maximum a posteriori probability (MAP) detection has attracted increasing attentions recent years. In this paper, we analytically study performance having optimally displaced threshold (ODTD) realistic situation noises and imperfect devices. We first prove that MAP for is equivalent to situation. Then analyze properties optimum displacement ODTD, propose heuristic greedy search algorithm design these parameters. ODTD asymptotically approaches when signal power large, also clarify connection between one-port homodyne detection. Numerical results show proposed can obtain lower smoother error than existing methods.