%0 Conference Paper
%A Willsch, Dennis
%T Observation of Josephson Harmonics in Tunnel Junctions
%I Chalmers University
%M FZJ-2023-01953
%D 2023
%X The Josephson effect is the keystone of quantum computing with superconductinghardware. In this talk, I will show that the celebrated sin(phi) Josephsonrelation fails to fully describe the measured energy spectra of many transmonsamples.  While the microscopic theory of Josephson junctions contains higherharmonics sin(2*phi), sin(3*phi), ..., these have generally been considerednegligible in tunnel junctions. However, this assumption is unjustified due tothe non-uniformity of the commonly used AlOx tunnel barriers, which can causehigh-transparency conduction channels. Indeed, by including the Josephsonharmonics in the transmon Hamiltonian, we can greatly improve the agreementbetween computed and measured energy spectra.  The observation of Josephsonharmonics in tunnel junctions prompts a reevaluation of our theoretical modelsfor superconducting hardware.
%B WACQT Virtual Workshop on Quantum Technology
%C 26 Apr 2023 - 27 Apr 2023, Online (Sweden)
Y2 26 Apr 2023 - 27 Apr 2023
M2 Online, Sweden
%F PUB:(DE-HGF)6
%9 Conference Presentation
%U https://juser.fz-juelich.de/record/1007055