Probing Sub-eV Dark Photon, Scalar and Axion-like Particle Dark Matters with Transmon Qubits

TL;DR

The paper addresses detecting sub-eV bosonic dark matter with transmon qubits by linking DM-induced phonons in superconductors to quasiparticle production, quantified via the steady-state balance $0=-\Gamma_R-\Gamma_T+\Gamma_G$ and the energy-loss function ${\rm Im}\left[-\frac{1}{\varepsilon(\omega)}\right]$. It derives constraints on three DM candidates—dark photons with kinetic mixing $\kappa$, scalar DM with coupling $d_{\phi ee}$, and axion-like particles with coupling $g_{aee}$—from existing transmon measurements, with projected sensitivities shown in the figures and conservative treatment of superconductivity within DarkELF. The results constitute the first direct laboratory constraints on these light bosonic DM models in the sub-eV mass range and highlight the potential of quantum-qubit devices for underground DM detection, especially as single-quasiparticle sensitivity becomes achievable. The study underlines the significance of quantum technologies as complementary probes for ultralight DM and outlines practical paths toward enhanced sensitivity, including noise mitigation and scalable multi-qubit architectures.

Abstract

In this paper, we investigate constraints of the transmon qubit, an improved version of the charge qubit, on bosonic light dark matters. Phonon excitations induced by the scattering or absorption of dark matter on a superconductor may destroy the Cooper pair, leading to the production of quasiparticles made by the electron. By measuring the production rate of the quasiparticle density, one may read out the coupling between dark matter and ordinary matter, assuming that these quasiparticles are solely induced by dark matter interactions. For the first time, we show constraints on the parameter space of the dark photon, light scalar dark matter, and axion-like particles from the measurement of quasiparticles in transmon qubit experiments. This study offers insights for the development of quantum qubit experiments aimed at the direct detection of dark matter in underground laboratories.

Figures (2)

• Figure 1: Left-panel: Projected sensitivity on the dark photon mixing $\kappa$ from the transmon qubit, based on a sensitivity $n_{\rm qp}\le 0.04 ~{\rm \mu m}^{-3}$. Existing DP-photon conversion limits (blue-shaded) and direct laboratory search results from haloscope and electron recoil experiments (light-brown) Caputo:2021eaa are shown for comparison. Right-panel: projected sensitivity on the scalar dark matter coupling $d_{\phi ee }$.
• Figure 2: Left-panel: Transmon qubit constraint on the light scalar DM, where the light-blue regime is excluded by the fifth force measurement Adelberger:2003zx and horizontal line is the limit of the White Dwarfs observations Bottaro:2023gep. Right-panel: Transmon qubit constraint on the axion-like particle in the $m_a-g_{aee}$ plane (solid), based on a sensitivity estimate with $n_{\rm qp}\le 0.04 ~{\rm \mu m}^{-3}$. The limit from measurements on the electron dipole moment $g_e-2$ is shown for comparison (red shaded). Other constraints are not included considering that $g_e-2$ results encompass all constraints of transmon qubit.