Andreev Quantum Dots

CRISTIAN URBINA; LEANDRO TOSI; MARCELO GOFFMAN; HUGUES POTHIER

Miyagi-Zao

Simposio; International Symposium ?Hybrid Quantum Systems 2017?; 2017

A single-channel phase-biased superconducting weak link hosts an Andreev bound state, i.e. a discrete subgap state which can be occupied by either zero, one or two quasiparticles. Such an ?Andreev quantum dot?, in which quasiparticles are trapped not by electrostatic barriers but by the superconducting phase gradient, constitutes a very simple playground to explore the foundations of mesoscopic superconductivity.We have implemented Andreev quantum dots using the simplest possible weak link: a one-atom contact between aluminum electrodes. Using circuit-QED like techniques we coherently manipulate the even states of the dot, and probe the dynamics of the trapping and un-trapping of individual quasiparticles [1].References[1] C. Janvier et al., Science 349, 1199 (2015)