Yu-Shiba-Rusinov clouds in quantum dot-superconductor devices via fast NRG algorithms
Peter Zalom, Institute of Physics of the Czech Academy of Sciences, Prague, The Czech Republic

Date, Time
25.11, 15:00 - 16:00

Location
Hybrif form: Link to MSTeams meeting + Prof. Kielich Auditorium

Quantum dot-superconductor (QD-SC) devices represent promising building blocks for various applications, e. g. quantum and fast classical computing. Their unbiased theoretical description is potentially possible via Numerical renormalization group (NRG), but is now limited only to relatively simple architectures with several questions regariding screening processes being presently unsolved.

In this talk, we therefore present a method for exact mappings of QD-SC devices into simpler systems. We first demonstrate the approach on a three-terminal device comprised of two phase-biased superconducting and one metallic lead [1,2]. Resulting spectral and transport properties are presented to be in accord with existing experimental and theoretical data. Theoretical conclusion about screening Yu-Shiba-Rusinov clouds are then given to support the conclusions of [3].

Next, we disconnect metallic lead(s) and show that modifications to discretization procedure of standard NRG are required when combined with the previously discussed mapping approach. The resulting theory is then applied to the QD-SC device comprised of just two phase-biased leads. The results are demonstrated to agree with the well-established NRG results, but are obtained faster by several orders which allows scalability for the more complex QD-SC devices, e. g. double nanowires or milti-terminal QD-SC devicess.

1. P. Zalom, V. Pokorný, and T. Novotný, Phys. Rev. B 103, 035419 (2021).
2. P. Zalom and T. Novotný, Phys. Rev. B 104, 035437 (2021).
3. C.P. Moca, I. Weymann, M. A. Werner, and G. Zaránd, PRL 127, 186804 (2021)