Quantum-enhanced sensing of axion dark matter with a transmon-based single microwave photon counter

TL;DR

This paper demonstrates a quantum-enhanced axion dark matter search using a superconducting transmon qubit as a microwave photon counter, significantly improving detection speed over traditional methods.

Contribution

It introduces a novel quantum sensing approach with a transmon-based photon counter, boosting axion search efficiency by a factor of 20 compared to quantum-limited linear amplifiers.

Findings

Enhanced search speed by a factor of 20.

Set a new standard for axion detection with resonant detectors.

Successfully monitored microwave photons and dark counts in real-time.

Abstract

We report an axion dark matter search with a haloscope equipped with a microwave photon counter. The haloscope is a tunable high quality factor 3-dimensional microwave cavity placed in a magnetic field. The photon counter, operated cyclically, maps an incoming microwave photon onto the state of a superconducting transmon qubit. The measurement protocol continuously monitors the power emitted by the haloscope cavity as well as the dark count background, and enables tuning of the cavity frequency to probe different axion masses. With this apparatus we enhance by a factor 20 the search speed that can be reached with quantum-limited linear amplifiers, and set a new standard for probing the existence of axions with resonant detectors.