The ambition of the project is to develop and realize conceptually novel and practical quantum limited SQN detector capable to reveal single MW photons for a photon frequency of ~10 GHz with the Heisenberg limit of sensitivity and the quantum limit noise with a view to apply it to the QUAX (QUaerere AXion) experiment, an INFN funded search for galactic axions by means of both ferromagnetic and normal “haloscopes” [1][2].

The specific objectives of our project are as follows:

  1. Development of a single microwave photon detector based on moderate size networks of interacting superconducting qubits utilizing both transmons and flux qubits.
  2. Development of the Parametric Down Conversion (PDC) microwave photon source based on the Traveling Wave Josephson Parametric Amplifier (TW-JPA) with a clock frequency of few kHz
  3. Integration of the PDC MW photon source with two single photon SQN detectors in a common setup to develop an heralded single photon source and to carry out the test of the detectors at single MW photons.
  4. Installation of the single photon SQN detector integrated with the single photon source as a calibration element in a He free refrigerator of the QUAX Collaboration.
  5. Experimental study of feasibility of the single microwave photon SQN detector for the “haloscope” type of axion searching using the axion conversion in a magnetic field.

[1] Barbieri et al., Phys. Dark Univ. 15, 135 (2017).

[2] N. Crescini et al., Eur. Phys. J. C 78, 703 (2018).