(Highly sensitive detection of single microwave photons with coherent quantum network of SUPERconducting qubits for searching GALactic AXions)


SUPERGALAX is a project supported by the European Commission in the framework of the FET-open (Future and Emerging Technologies) call of the Horizon 2020 program.

This project is a proposal for a novel approach to acquisition of extremely low energy microwave signals (~1 GHz), based on the general concept of a passive quantum detection. For such highly sensitive detector (quantum antenna) the key novel concept we intend to use is the coherent quantum network composed of a large amount of strongly interacting superconducting qubits embedded in a low dissipative superconducting resonator.

Aim of the project is the fabrication and exploration of the dynamics of coherent quantum networks based on two types of superconducting qubits: transmons and flux qubits. A spatially distributed network of superconducting qubits interacting off-resonance with the incoming radiation, shows the collective ac Stark effect that can be measured even in the limit of single photon counting. The interaction of the signal with the collective quantum states occurring in the network of superconducting qubits has the fundamental character of a quantum non-demolition measurement, whereby the quantum states of the signal and the collective states of qubits become gradually entangled.

Assessment of the progress will be done by testing arrays with increasing number of superconducting qubits by using complementary experiments with different single photon sources. The feasibility of the superconducting network detector for galactic dark matter axions search will be finaly tested by an axion conversion experiment in a magnetic field.