Title: Performance advantage of quantum hypothesis testing for partially coherent optical sources

Abstract: Determining the presence of a potential optical source in the interest region is important for an imaging system and can be achieved by using hypothesis testing. The previous studies assume that the potential source is completely incoherent. In this paper, this problem is generalized to the scenario with partially coherent sources and any prior probabilities. We compare the error probability limit given by the quantum Helstrom bound with the error probability given by direct decision based on the prior probability. On this basis, the quantum-optimal detection advantage and detection-useless region are analyzed. For practical purposes, we propose a specific detection strategy using binary spatial-mode demultiplexing, which can be used in the scenarios without any prior information. This strategy shows superior detection performance and the results hold prospects for achieving super-resolved microscopic and astronomical imaging.