Jens Paaske, Niels Bohr Institute

Microwave response of superconducting sub-gap states

When: 11:00-12:00 CET, November 10th (Thursday), 2022

Where: Seminar Room, ICMM-CSIC, Campus de Cantoblanco, Madrid

Josephson junctions spanning a Coulomb-blockaded quantum dot host subgap states with a characteristic dispersion with phase difference and gate voltage, which to a large extent determine the microwave response of the junction. In this lecture, I will present our calculations of this linear microwave response, with special emphasis on spinful (odd occupied) quantum dots giving rise to Yu-Shiba-Rusinov bound states and the accompanying interaction driven quantum phase transition from π- to 0-junction behavior. I shall also discuss the intricate dc current response of a Josephson junction based on a double quantum dot with two phase shifted microwave tones on the individual gate voltages. This is shown to lead to a tunable phi_0 junction and to allow for supercurrent rectification.

YouTube link: https://www.youtube.com/watch?v=gFviD0Ktypc

[1] Cecilie Hermansen, Alfredo Levy Yeyati, JP, Phys. Rev. B 105, 054503 (2022)
[2] Carlos Ortega-Taberner, Antti-Pekka Jauho, JP; arXiv:2207.06152