A Superconducting Single Microwave Photon Detector Enabled by Dissipation Engineering - Experiment

Superconducting circuits carry microwave photons five orders of magnitude lower in energy than photons of visible light. For their detection, one must bridge the gap between these low energy excitations and signals measurable by standard microwave electronics. In this work, we develop a new class of detectors, based on dissipation engineering, that perform quantum non demolition measurements of travelling microwave wavepackets. We fabricated and measured a single microwave photon detector that imprints on a transmon qubit the passage of a single photon without destroying it. The key advantage of this scheme is its intrinsic robustness against the main decoherence mechanisms found in these circuits, leading to both low dark counts, high detection efficiency and continuous operation, paving the way towards applications in quantum sensing and computing.