Microwave Photon Detection at Parametric Criticality

Abstract

The detection of microwave fields at single-photon power levels is a much-sought-after technology, with practical applications in nanoelectronics and quantum information science. Here we demonstrate a simple yet powerful criticality-enhanced method of microwave photon detection by operating a magnetic-field-tunable Kerr Josephson parametric amplifier at the border of a first-order phase transition and close to the critical point. We obtain an efficiency of 73% and a dark-count rate of 167 kHz, corresponding to a responsivity of 1.3×1017W−1 and noise-equivalent power of 3.28 zW/Hz. We verify the single-photon operation by extracting the Poissonian statistics of a coherent probe signal. Published by the American Physical Society 2024