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TT: Fachverband Tiefe Temperaturen

TT 76: Superconductivity: Tunnelling and Josephson Junctions II

TT 76.3: Talk

Thursday, March 21, 2024, 15:30–15:45, H 3010

Quartet Tomography in Multiterminal Josephson Junctions — •David Christian Ohnmacht¹, Marco Coraiola², Juan Jose García-Esteban^1,3, Deividas Sabonis², Fabrizio Nichele², Wolfgang Belzig¹, and Juan Carlos Cuevas^1,3 — ¹Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany — ²IBM Research Europe—Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland — ³Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain

We investigate the detection of quartets in hybrid multiterminal Josephson junctions [1]. Using simple models of quantum dots coupled to superconducting leads, we find that quartets are ubiquitous and show how to rigorously extract their contribution to the current-phase relation (CPR). We also demonstrate that quartets are closely related to the hybridization of Andreev bound states (ABSs) in these systems and propose a method to identify quartets directly in ABS spectra. We illustrate our method by analyzing the spectroscopic measurements of the ABS spectrum in a threeterminal Josephson junction realized in an InAs/Al heterostructure [2]. Our analysis strongly suggests the existence of quartets in the studied hybrid system.

[1] D. C. Ohnmacht et. al., arXiv:2311.18544 (2023)

[2] M. Coraiola et. al., Nat. Commun. 14 (2023) 6784

Keywords: Superconductivity; Josephson effect; Andreev reflection; Superconducting devices; Quartets