Hugues Pothier, L. Tosi, C. Metzger, M. Goffman and C. Urbina

Quantronics group

SPEC, CEA Saclay, CNRS, Université Paris-Saclay, France

Andreev states are localized quasiparticle states that arise at phase-biased Josephson junctions. With microwaves, a Cooper pair from the superconducting condensate can be excited and create a pair of quasiparticles in an Andreev state¹. In transparent junctions, like the ones obtained in atomic contacts or nanowires, the two-level system spanned by the states with 0 and 2 quasiparticles is well decoupled from other excitations. I will report experiments in which the dynamics and the coherence of this system is probed by coupling it to a microwave resonator².

1. L. Bretheau et al., Exciting Andreev pairs in a superconducting atomic contact, Nature 499, 312-315 (2013).

2. C. Janvier et al., Coherent manipulation of Andreev states in superconducting atomic contacts, Science 349, 1199 (2015).

This seminar is organized in the framework of the PSI2 program "Topological phases of matter: from the quantum Hall effect to spin liquids" (Topmat)
https://topmat.sciencesconf.org/