Error performance and robustness of optimum quantum detection for MPSK signals in the presence of phase noise

In quantum communications, the performance of a quantum measurement with phase noise has not widely been discussed. In this paper, we focus on error performance, as well as robustness, in a comparison with a classical measurement using multiple phase-shift keying when phase noise is generated. With increasing signal dimension, we analyze numerically the trend in robustness in terms of the error performance and the gain in robustness.