Институт теоретической физики им. Л.Д. Ландау РАН
L.D. Landau Institute for Theoretical Physics RAS
Research in superconductivity and beyond Gerasim Eliashberg memorial conference
August, 23-26, 2021
Coherent dynamics of Andreev levels in Josephson weak links
Date/Time: 13:00 25-Aug-2021
In this talk, I will present measurements of the spectrum and the coherent dynamics of Andreev levels in two types of superconducting phase-biased weak links: single-atom contacts and semiconducting nanowire junctions. In the former, the weak link is typically characterized by a single well transmitted channel hosting a pair of Andreev bound states which can be populated with zero, one or two quasiparticles, leading to three many body states |g⟩, |o⟩ and |e⟩, where the odd state |o⟩ is two-fold degenerate due to spin. In the latter, spin-orbit interaction lifts this degeneracy opening a path towards Andreev spin qubits. Using circuit QED-techniques, we perform relaxation, Ramsey, and echo experiments and analyze the time evolution of the populations of the different many-body states for different weak link configurations. I will discuss the evolution of the extracted rates as a function of the superconducting phase and gate bias and the possible mechanisms at play.
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