Conference Presentation (Invited)

FZJ-2023-01953

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Observation of Josephson Harmonics in Tunnel Junctions

Willsch, D. (Corresponding author)FZJ*

2023

Please use a persistent id in citations: http://hdl.handle.net/2128/34357

Abstract: 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.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)

Appears in the scientific report 2023

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Database coverage:

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