Localized Excitations in Superconducting Atomic Contacts: PROBING THE ANDREEV DOUBLET

Landry Bretheau 1
1 QUANTRONICS - Quantronics Group
SPEC - UMR3680 - Service de physique de l'état condensé, IRAMIS - Institut Rayonnement Matière de Saclay
Abstract : This thesis discusses two experiments highlighting the existence of a fermionic degree of freedom in the Josephson effect: the Andreev doublet. They are both performed on the most basic Josephson element, a one-atom contact between two superconducting electrodes. In the first one, we observed the disappearance of the supercurrent, which reflects the spontaneous trapping of a quasiparticle in one of two Andreev bound states. In the second experiment we achieved the photon-absorption spectroscopy of this two-level system, using a Josephson junction as an integrated on-chip microwave emitter and detector. The observed spectra are well accounted for by a spin-boson model including the Andreev doublet and an electromagnetic mode of the environment.
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Submitted on : Sunday, September 15, 2013 - 6:05:18 PM
Last modification on : Thursday, January 24, 2019 - 1:14:02 AM


  • HAL Id : pastel-00862029, version 1


Landry Bretheau. Localized Excitations in Superconducting Atomic Contacts: PROBING THE ANDREEV DOUBLET. Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]. Ecole Polytechnique X, 2013. English. ⟨pastel-00862029⟩



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