Seminars 2025

This series of informative seminars on quantum technologies has the goal of providing an introduction on the hottest topics in the field. The targeted audience includes students and non expert researchers.

Those who are interested to attend to the seminars are invited to subscribe the mailing
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BiQuTE Seminar committee: A. Giachero, A. Zaffaroni (Dip. Fisica), F. Pezzoli (Dip. Scienze dei Materiali),  A. Leporati (Dip. di Informatica, Sistemistica e Comunicazione)

Improved modelling of superconducting circuits

Gianluigi Catelani
(Forschungszentrum Jülich, Germany
& Technology Innovation Institute, UAE)

Jan 13th 2025, 11.30 CEST
Physics Department U2, Room U1-13 (+zoom)
Università di Milano-Bicocca
Piazza della Scienza 3, 20126 Milan

Abstract and material

More accurate control and reduced losses are needed for superconducting circuits to move beyond the current NISQ era in quantum computing applications and to devise better detectors. In this talk I will discuss some recent advances and their impacts on designing superconducting devices. After briefly reviewing the standard tunnel model of a Josephson junction, I will introduce a more realistic model which is needed to accurately describe qubit spectroscopic data [1]. Next, I will show how a form of so-called “gap engineering’’, in which the values of the superconducting gap on the two sides of a junction are properly chosen, can mitigate errors related to quasiparticles [2,3]. Finally, I will consider the role of pair-breaking photons in limiting a resonator quality factor [4].

[1] D. Willsch et al., Nat. Phys. 20, 815–821 (2024)
[2] G. Marchegiani et al., PRX Quantum 3, 040338 (2022)
[3] J. Krause et al., Phys. Rev. Applied 22, 044063 (2024)
[4] P. B. Fischer and G. Catelani, SciPost Phys. 17, 070 (2024)

Indico (with zoom link) - slides - video recording