The use of superconducting systems such as qubits, Josephson parametric amplifiers, circuit QED etc., allows the detection of single photons in the microwave range , a very difficult task because of the low energy of the photons involved. This make potentially accessible a series of important applications such as quantum computing, quantum metrology, ultrasensitive spectrum analysis of cryogenic environment, cosmic background radiation detection, search for exotic particles and so on . In particular, single microwave-photon superconducting detectors can be a very important tool for the search of axion dark matter . We present a proposal and discuss perspectives and issues in this direction.
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