Characterization of qubit dephasing by Landau-Zener-Stückelberg-Majorana interferometry.

We are grateful for financial support from the DFG via SFB-631 and the Cluster of Excellence “Nanosystems Initiative Munich (NIM)” and by the Spanish Ministry of Economy and Competitiveness through Grant No. MAT2011-24331. S. L. acknowledges support via a Heisenberg fellowship of the DFG. F. F. and G. P. contributed equally to this work.