Regensburg 2019 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 55: Superconductivity: Tunneling and Josephson Junctions

TT 55.12: Talk

Thursday, April 4, 2019, 12:30–12:45, H23

Microwave spectroscopy reveals the quantum geometric tensor of topological Josephson matter — •Raffael L. Klees¹, Gianluca Rastelli¹, Juan Carlos Cuevas², and Wolfgang Belzig¹ — ¹Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany — ²Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain

Concepts like Chern numbers and their relation to physical phenomena have become very familiar, but actually, key quantities like the quantum geometric tensor [1], which provides a much deeper information about quantum states, remain experimentally difficult to access. Recently it has been shown that multiterminal superconducting junctions constitute an ideal playground to mimic topological systems in a controlled manner [2]. We study the spectrum of Andreev bound states in topological Josephson matter and demonstrate that the quantum geometric tensor of the ground state manifold can be extracted with the help of microwave spectroscopy [3]. We develop the concept of artificially polarized microwaves, which can be used to obtain both the quantum metric tensor and the Berry curvature. The quantized integrated absorption provides a direct evidence of topological quantum properties of the Andreev states.
M. Kolodrubetz et al., Phys. Rep. 697, 1 (2017)
R.-P. Riwar et al., Nat. Commun. 7, 11167 (2016);
J. S. Meyer and M. Houzet, Phys. Rev. Lett. 119, 136807 (2017);
H.-Y. Xie et al., Phys. Rev. B 96, 161406 (2017);
Phys. Rev. B 97, 035443 (2018). [3] R. L. Klees et al., arXiv:1810.11277