We propose to exploit currently available tunnel ferromagnetic Josephson junctions to realize a hybrid superconducting qubit. We show that the characteristic hysteretic behavior of the ferromagnetic barrier provides an alternative and intrinsically digital tuning of the qubit frequency by means of magnetic field pulses. To illustrate functionalities and limitation of the device, we discuss the coupling to a read-out resonator and the effect of magnetic fluctuations. The possibility to use the qubit as a noise detector and its relevance to investigate the subtle interplay of magnetism and superconductivity is envisaged.
@article{arxiv.2206.00715,
title = {A hybrid ferromagnetic transmon qubit: circuit design, feasibility and detection protocols for magnetic fluctuations},
author = {Halima Giovanna Ahmad and Valentina Brosco and Alessandro Miano and Luigi Di Palma and Marco Arzeo and Domenico Montemurro and Procolo Lucignano and Giovanni Piero Pepe and Francesco Tafuri and Rosario Fazio and Davide Massarotti},
journal= {arXiv preprint arXiv:2206.00715},
year = {2022}
}