The experiments that we propose deal with single atom contacts between superconducting electrodes. In this model system of mesoscopic superconductivity, which can be fabricated in a controlled way and fully characterized, it is predicted that the supercurrent in carried by Cooper pairs localized in the vicinity of the atom: the Andreev states. Each of these Cooper pairs can be in two states, which carry opposite supercurrents. In order to do the spectroscopy of these states, we want to couple an atomic contact to a voltage-biased Josephson junction, which implements both a local microwave source and a detector. Spectroscopy allows to access the lifetime of the states, which will then be optimized towards their coherent manipulation.



The thesis will include sample fabrication (electron-beam lithogaphy, thin films deposition), measurement in a dilution refrigerator (at 20 mK), and of course data analysis and modelisation.



This project is lead by the two memebers of the group, by a PhD student (finishing in Fébruary 2013) and a post-doc.