Transmon qubit modeling and characterization for Dark Matter search
Abstract
This study presents the design, simulation, and experimental characterization of a superconducting transmon qubit circuit prototype for potential applications in dark matter detection experiments. We describe a planar circuit design featuring two non-interacting transmon qubits, one with fixed frequency and the other flux tunable. Finite-element simulations were employed to extract key Hamiltonian parameters and optimize component geometries. The qubit was fabricated and then characterized at mK, allowing for a comparison between simulated and measured qubit parameters. Good agreement was found for transition frequencies and anharmonicities (within 1\% and 10\% respectively) while coupling strengths exhibited larger discrepancies (30\%). We discuss potential causes for measured coherence times falling below expectations (1-2 \textmu s) and propose strategies for future design improvements. Notably, we demonstrate the application of a hybrid 3D-2D simulation approach for energy participation ratio evaluation, yielding a more accurate estimation of dielectric losses. This work represents an important first step in developing planar Quantum Non-Demolition (QND) single-photon counters for dark matter searches, particularly for axion and dark photon detection schemes.
Keywords
Cite
@article{arxiv.2409.05988,
title = {Transmon qubit modeling and characterization for Dark Matter search},
author = {R. Moretti and D. Labranca and P. Campana and R. Carobene and M. Gobbo and M. A. Castellanos-Beltran and D. Olaya and P. F. Hopkins and L. Banchi and M. Borghesi and A. Candido and S. Carrazza and H. A. Corti and A. D'Elia and M. Faverzani and E. Ferri and A. Nucciotti and L. Origo and A. Pasquale and A. S. Piedjou Komnang and A. Rettaroli and S. Tocci and C. Gatti and A. Giachero},
journal= {arXiv preprint arXiv:2409.05988},
year = {2025}
}