article published yes Maxim Tjøtta author Devashish C Shah author de191434-4e7e-11ef-bf4b-9a056fc19fc30009-0007-5829-7707 Kanishk Modi author f05345fd-900f-11f1-bfd8-8c0b6eadcc7f Marco Valentini author C0BB2FAC-D767-11E9-B658-BC13E6697425 Rubén Seoane Souto author Georgios Katsaros author 38DB5788-F248-11E8-B48F-1D18A9856A870000-0001-8342-202X Jeroen Danon author GeKa department GradSch department Superconducting spin qubits in planar Ge project Extracting the current-phase relationship (CPR) of a single superconducting junction is challenging in practice and traditionally involves embedding the junction in a larger superconducting circuit containing SQUIDs and/or resonators. Applying ac driving to the junction has proven to be a viable and less invasive way to extract information about the few lowest harmonics of the CPR, by locating the integer and fractional Shapiro steps in the 𝐼⁢𝑉-curve of the driven junction. Here, we present an alternative driving-based method that allows to extract the full harmonic content of a CPR in a relatively noninvasive way, by fitting the measured critical currents of the driven junction as a function of driving power. We test our method, both using numerical simulations and in experiments, and we show that it works accurately. American Physical Society2026 eng 2331-7019 2511.1431310.1103/d3gl-qntm 264 Tjøtta, Maxim, Devashish C Shah, Kanishk Modi, Marco Valentini, Rubén Seoane Souto, Georgios Katsaros, and Jeroen Danon. “Fast-Driving Spectroscopy of Current-Phase Relationships of Individual Josephson Elements.” <i>Physical Review Applied</i>. American Physical Society, 2026. <a href="https://doi.org/10.1103/d3gl-qntm">https://doi.org/10.1103/d3gl-qntm</a>. Tjøtta M, Shah DC, Modi K, Valentini M, Seoane Souto R, Katsaros G, Danon J. 2026. Fast-driving spectroscopy of current-phase relationships of individual Josephson elements. Physical Review Applied. 26(4), 044017. Tjøtta, M., Shah, D. C., Modi, K., Valentini, M., Seoane Souto, R., Katsaros, G., &#38; Danon, J. (2026). Fast-driving spectroscopy of current-phase relationships of individual Josephson elements. <i>Physical Review Applied</i>. American Physical Society. <a href="https://doi.org/10.1103/d3gl-qntm">https://doi.org/10.1103/d3gl-qntm</a> M. Tjøtta, D.C. Shah, K. Modi, M. Valentini, R. Seoane Souto, G. Katsaros, J. Danon, Physical Review Applied 26 (2026). Tjøtta M, Shah DC, Modi K, et al. Fast-driving spectroscopy of current-phase relationships of individual Josephson elements. <i>Physical Review Applied</i>. 2026;26(4). doi:<a href="https://doi.org/10.1103/d3gl-qntm">10.1103/d3gl-qntm</a> M. Tjøtta <i>et al.</i>, “Fast-driving spectroscopy of current-phase relationships of individual Josephson elements,” <i>Physical Review Applied</i>, vol. 26, no. 4. American Physical Society, 2026. Tjøtta, Maxim, et al. “Fast-Driving Spectroscopy of Current-Phase Relationships of Individual Josephson Elements.” <i>Physical Review Applied</i>, vol. 26, no. 4, 044017, American Physical Society, 2026, doi:<a href="https://doi.org/10.1103/d3gl-qntm">10.1103/d3gl-qntm</a>. 231562026-10-18T22:01:52Z2026-10-19T07:25:01Z