Quantum efficiency of a single microwave photon detector based on a current-biased Josephson junction

Amrit Poudel, Canran Xu, Maxim Vavilov

Zechariah Thrailkill, Joseph Lambert, Steven A. Carabello +2 more

Amrit Poudel, Robert McDermott, Maxim Vavilov

We analyze the quantum efficiency of a microwave photon detector based on a current-biased Josephson junction. We consider the Jaynes-Cummings Hamiltonian to describe coupling between the photon field and the junction. We then take into account the coupling of the junction and the resonator to the environment. We solve the equation of motion of the density matrix of the resonator-junction system to compute the quantum efficiency of the detector as a function of detection time, bias current, and energy relaxation time. Our results indicate that junctions with modest coherence properties can provide efficient detection of single microwave photons, with quantum efficiency in excess of $80%$.

A. Rettaroli, D. Alesini, D. Babusci +17 more

Detection of light dark matter, such as axion-like particles, puts stringent requirements on the efficiency and dark-count rates of microwave-photon detectors. The possibility of operating a current-biased Josephson junction as a single-microwave photon-detector was investigated through numerical simulations, and through an initial characterization of two Al junctions fabricated by shadow mask evaporation, done in a dilution refrigerator by measuring escape currents at different temperatures, from 40 mK up to the Al transition temperature. The escape dynamics of the junctions were reproduced in the simulation, including the dissipative effects. Inhibition of thermal activation was observed, leaving the macroscopic quantum tunneling as the dominant effect well beyond the crossover temperature.

Ivan Iakoupov, Yuichiro Matsuzaki, William J. Munro +1 more

K. Inomata, Lin Zhirong, Kazuki Koshino +4 more