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TT: Fachverband Tiefe Temperaturen
TT 6: Superconductivity: Tunnelling and Josephson Junctions I
TT 6.11: Talk
Monday, March 18, 2024, 12:30–12:45, H 3010
Non-Hermitian phase-biased Josephson junctions — •Jorge Cayao1 and Masatoshi Sato2 — 1Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden — 2Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
We study non-Hermitian Josephson junctions formed by conventional superconductors with a finite phase difference under non-Hermiticity naturally appearing due to coupling to normal reservoirs. Depending on the structure of non-Hermiticity, the low-energy spectrum hosts topologically stable exceptional points either at zero or finite real energies as a function of the superconducting phase difference. Interestingly, we find that the corresponding phase-biased supercurrents acquire divergent profiles at such exceptional points, an instance that turns out to be a natural and unique non-Hermitian effect signalling a possible way to enhance the sensitivity of Josephson junctions.
Keywords: Non-Hermitian Josephson junctions; Andreev bound states; Current-phase curves; Andreev exceptional points