Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 9: Quantum Dots, Quantum Wires, Point Contacts
TT 9.7: Vortrag
Montag, 12. März 2018, 11:15–11:30, HFT-FT 101
Simple transformation between symmetrically and asymmetrically coupled superconducting quantum dots — •Martin Žonda1,2, Alžběta Kadlecová2, and Tomáš Novotný2 — 1Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany — 2Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
We will present simple, yet very powerful correspondence between the characteristics of a single-level quantum dot coupled symmetrically to two phase-biased superconducting leads with its asymmetrically coupled equivalents. Counter-intuitively, it is the symmetric setup which is the most general one and its characterization enables full description of any equivalent asymmetrically coupled system. This discovery makes it possible to utilize known results for symmetric setups in general asymmetric cases via trivial analytical relations. We will present ready-to-use conversion formulas for the 0−π phase transition boundary, on-dot quantities, and the Josephson current and illustrate them on the numerical renormalization group results. The formulas also provide an efficient tool for estimating the coupling asymmetry directly from the experimental data, which is otherwise a demanding task. We will demonstrate this by analysing recent 0−π transition measurements [1].
Delagrange et al., Phys. Rev. B 93, 195437 (2016).