Freiburg 2019 – scientific programme
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FM: Fall Meeting
FM 59: Enabling Technologies: Quantum Dots and Superconductivity-based Systems
FM 59.8: Talk
Wednesday, September 25, 2019, 15:45–16:00, 3043
Microwave spectroscopy reveals the quantum geometric tensor of topological Josephson matter — Raffael Klees1, Gianluca Rastelli1, Juan Carlos Cuevas2, and •Wolfgang Belzig1 — 1Department of Physics, University of Konstanz, Germany — 2Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de 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. [1] M. Kolodrubetz et al., Phys. Rep. 697, 1 (2017) [2] R.-P. Riwar et al., Nat. Commun. 7, 11167 (2016); [3] R. L. Klees et al., arXiv:1810.11277