Speaker
Description
Ultralight bosonic dark matter candidates, such as axions, axion-like particles, and dark photons, can behave as classical coherent fields oscillating at frequencies set by the particle mass. In the microwave regime, this motivates detection strategies based on superconducting quantum devices, where near-quantum-limited amplification and single-excitation sensitivity can probe extremely weak interactions.
We present two complementary superconducting approaches. First, we describe a kinetic inductance traveling wave parametric amplifier (KTWPA) based on 10 nm-thick NbTiN films targeting the 10–14 GHz band, intended as the readout amplifier for broadband dish antenna experiments such as GigaBREAD, which simultaneously scan a wide frequency range in search of bosonic dark matter. Building on prior generations with >20 dB gain and near-quantum-limited noise over 4–8 GHz [1], KTWPAs are particularly well suited for axion searches as they are resilient to the Tesla-scale magnetic fields required for detection. We report on gain, bandwidth, and noise performance of these next-generation devices.
Second, we present a transmon-based direct detection scheme in which a flux-tunable qubit acts as an absorptive sensor for dark matter-induced electromagnetic excitations. Broadband exploration is achieved by sweeping the qubit frequency through repeated interaction and readout cycles. We further introduce a quantum-enhanced protocol coupling two sensing qubits to a common ancilla with post-selection, amplifying the sensor response to small excitation probabilities [2]. A noise-aware analysis quantifies the sensitivity gain over direct single-qubit sensing.
Together, these approaches represent a scalable strategy for probing new dark sector parameter space with superconducting quantum hardware.
References:
[1] L. Howe, A. Giachero et al. arXiv:2507.07706 [quant-ph]
[2] R. Moretti at al. arXiv:2603.03157 [quant-ph]
Authors:
A. Giachero(1,2,3,4), J. Austermann(4), D. A. Bennett(4), S. P. Benz(4), M. Borghesi(1,2), P. Campana(1,2), R. Carobene(1,2), A. Cattaneo(1,2), M. A. Castellanos-Beltran(4), M. Erickson(5,4), M. Faverzani(1,2), E. Ferri(2), M. Gobbo(1,2), L. Howe(3,4), P. F. Hopkins(4), J. Hubmayr(4), D. I. Olaya(3,4), D. Labranca(1,2), R. Moretti(1,2), A. Nucciotti(1,2), A. J. Sirois(4), C. Shiu(4), P. Szypryt(4), J.N. Ullom(3,4), M.R. Vissers(4), J.D. Wheeler(4)
1 Department of Physics, University of Milano-Bicocca, Milan, 20126, Italy
2 INFN - Milano-Bicocca, Milan, 20126, Italy
3 Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
4 National Institute of Standards and Technology, Boulder, Colorado 80305, USA
5 Department of Electrical, Energy, and Computer Engineering, University of Colorado, Boulder, 80309, Colorado