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arXiv:2404.04423 · Physical review. D/Physical review. D.

Estimating the energy threshold of phonon-mediated superconducting qubit detectors operated in an energy-relaxation sensing scheme

R. Linehan, Israel Hernandez, Dylan J. Temples, S. Q. Dang, D. Baxter, Lauren Hsu, Enectali Figueroa-Feliciano, Rakshya Khatiwada, K. Anyang, D. Bowring, G. Bratrud, Gustavo I. Cancelo, Aaron S. Chou, R. Gualtieri, Kelly Stifter, Sara Sussman

Published Mar 18, 2025• 10 citations
arXivHTMLPDF

Abstract

In recent years, the lack of a conclusive detection of weakly interacting massive particle dark matter at the $10\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$ mass scale and above has encouraged development of low-threshold detector technology aimed at probing lighter dark matter candidates. Detectors based on Cooper-pair-breaking sensors have emerged as a promising avenue for this detection due to the low (meV-scale) energy required for breaking a Cooper pair in most superconductors. Among them, devices based on superconducting qubits are interesting candidates for sensing due to their observed sensitivity to broken Cooper pairs. We have developed an end-to-end g4cmp-based simulation framework and have used it to evaluate performance metrics of qubit-based devices operating in a gate-based ``energy relaxation'' readout scheme, akin to those used in recent studies of qubit sensitivity to ionizing radiation. We find that for this readout scheme, the qubit acts as a phonon sensor with an energy threshold ranging down to $\ensuremath{\simeq}0.4\text{ }\text{ }\mathrm{eV}$ for near-term performance parameters.

DOI
10.1103/physrevd.111.063047

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In recent years, the lack of a conclusive detection of weakly interacting massive particle dark matter at the 10  GeV/c210\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}10  GeV/c2 mass scale and above has encouraged development of low-threshold detector technology aimed at probing lighter dark matter candidates. Detectors based on Cooper-pair-breaking sensors have emerged as a promising avenue for this detection due to the low (meV-scale) energy required for breaking a Cooper pair in most superconductors. Among them, devices based on superconducting qubits are interesting candidates for sensing due to their observed sensitivity to broken Cooper pairs. We have developed an end-to-end g4cmp-based simulation framework and have used it to evaluate performance metrics of qubit-based devices operating in a gate-based ``energy relaxation'' readout scheme, akin to those used in recent studies of qubit sensitivity to ionizing radiation. We find that for this readout scheme, the qubit acts as a phonon sensor with an energy threshold ranging down to \ensuremath≃0.4  eV\ensuremath{\simeq}0.4\text{ }\text{ }\mathrm{eV}\ensuremath≃0.4  eV for near-term performance parameters.
The next generation of rare-event searches, such as those aimed at determining the nature of particle dark matter or measuring fundamental neutrino properties, will benefit from particle detectors with thresholds at the meV scale, 100 – 1000 × lower than currently available. Quantum parity detectors (QPDs) are a class of proposed quantum devices, extending recent work on superconducting qubit sensors, that exploit the fingerprints of single quasiparticle tunneling across a coherent weak link as their detection concept. As envisioned, phonons generated by particle interactions within a crystalline substrate cause an eventual quasiparticle cascade within a surface-patterned superconducting qubit element. This process alters the fundamental charge parity of the device in a binary manner, which can be used to deduce the initial properties of the energy deposition. This work lays out multiple resonator-coupled readout schemes depending on qubit architecture, provides an analytic formulation for reconstructing sensor energies, and details strategies for multiplexing large arrays of sensors. We further compute the sensitivity of QPDs and detail an R&D pathway to demonstrating sub-eV energy deposit thresholds.
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