Fast-driving spectroscopy of current-phase relationships of individual Josephson elements Tjøtta, Maxim Shah, Devashish C ; https://orcid.org/0009-0007-5829-7707 Modi, Kanishk Valentini, Marco Seoane Souto, Rubén Katsaros, Georgios ; https://orcid.org/0000-0001-8342-202X Danon, Jeroen 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 Society 2026 info:eu-repo/semantics/article doc-type:Article Article http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/23156 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> eng info:eu-repo/semantics/altIdentifier/doi/10.1103/d3gl-qntm info:eu-repo/semantics/altIdentifier/e-issn/2331-7019 info:eu-repo/semantics/altIdentifier/arxiv/2511.14313 info:eu-repo/semantics/openAccess