The Superconducting Quasiparticle-Amplifying Transmon: A Qubit-Based Sensor for meV Scale Phonons and Single THz Photons

TL;DR

This paper introduces SQUATs, a novel superconducting qubit-based sensor that amplifies quasiparticles, enabling detection of single THz photons and meV phonons with potential applications in quantum sensing and particle detection.

Contribution

The paper proposes a new sensor design combining transmon qubits with quasiparticle amplification, enhancing detection capabilities for low-energy particles and photons.

Findings

Predicted sensitivity to single THz photons.

Achieves detection of 1 meV phonons in microsecond timescale.

Design leverages existing superconducting qubit technology.

Abstract

With great interest from the quantum computing community, an immense amount of R&D effort has been invested into improving superconducting qubits. The technologies developed for the design and fabrication of these qubits can be directly applied to applications for ultra-low threshold particle detectors, e.g. low-mass dark matter and far-IR photon sensing. We propose a novel sensor based on the transmon qubit architecture combined with a signal-enhancing superconducting quasiparticle amplification stage. We refer to these sensors as SQUATs: Superconducting Quasiparticle-Amplifying Transmons. We detail the operating principle and design of this new sensor and predict that with minimal R&D effort, solid-state based detectors patterned with these sensors can achieve sensitivity to single THz photons, and sensitivity to $1\,\mathrm{meV}$ phonons in the detector absorber substrate on the $\mu\mathrm{s}$ timescale.