The exciting life of quasiparticles trapped between superconductors

DIPC Seminars

Speaker

Cristian Urbina
Quantronics Group, SPEC (CNRS), CEA-Saclay, Université Paris-Saclay, France

When

2024/01/10
12:00

Place

Donostia International Physics Center (Hybrid Seminar)

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In a non-superconducting material linking two superconductors, discrete quasiparticles states are formed as electrons and holes are “transmuted” into each other through successive Andreev reflection processes at both interfaces. The energy of these Andreev bound states depends on the phase difference between the complex order parameters of the superconductors. As a result, such a “weak link” carries a supercurrent and behaves as an inductance that depends on the occupation of the Andreev states.
I will review a series of experiments performed on semiconducting nanowire weak links [1,2,3] relying on the techniques of “circuit Quantum Electrodynamics”, which consist in probing a quantum circuit through a coupled resonator [4]. They reveal the rich physics of Andreev Bound States, from the basics to the effects of spin-orbit coupling and of Coulomb interactions.

[1] Spin-Orbit Splitting of Andreev States Revealed by Microwave Spectroscopy, L. Tosi, C. Metzger, M. F. Goffman, C. Urbina, H. Pothier, Sunghun Park, A. Levy Yeyati, J. Nygård, and P. Krogstrup, Phys. Rev. X 9, 011010 (2019).
[2] Circuit-QED with phase-biased Josephson weak links, C. Metzger, Sunghun Park, L. Tosi, C. Janvier, A. A. Reynoso, M. F. Goffman, C. Urbina, A. Levy Yeyati, and H. Pothier, Phys. Rev. Research 3, 013036 (2021).
[3] Signatures of interactions in the Andreev spectrum of nanowire Josephson junctions, F. J. Matute Cañadas, C. Metzger, Sunghun Park, L. Tosi, P. Krogstrup, J. Nygård, M. F. Goffman, C. Urbina, H. Pothier, A. Levy Yeyati, https://arxiv.org/abs/2112.05625.
[4] From Adiabatic to Dispersive Readout of Quantum Circuits, Sunghun Park, C. Metzger, L. Tosi, M. F. Goffman, C. Urbina, H. Pothier, and A. Levy Yeyati, Phys. Rev. Lett. 125, 077701 (2020).

Zoom: https://dipc-org.zoom.us/j/99842361858
Youtube: https://youtube.com/live/V3EGPCUfSHw