Navigation and service

PGI Colloquium
Prof. Dr. Alexey Ustinov
(Karlsruher Institut für Technologie)

PGI Lecture Hall, Building 04.8, 2nd floor, Room 365

04 Jul 2014 11:00
04 Jul 2014

Coherent manipulation of single atomic-scale defects in amorphous oxides

In structurally disordered solids, some atoms or small groups of atoms are able to quantum mechanically tunnel between two nearly equivalent sites. These atomic tunneling systems have been identified as the cause of various low-temperature anomalies of bulk glasses and as a source of decoherence of superconducting quantum circuits where they are sparsely present in the disordered oxide barriers of Josephson junctions. A tiny deformation of the oxide barrier changes the energies of the atomic tunneling systems. We have measured these changes by microwave spectroscopy of the superconducting qubit through coherent interactions between these two quantum systems. By tracing the dependence of the energy splitting of atomic tunneling states on external strain, we have verified a central hypothesis of the two-level tunneling model for disordered solids.


Prof. Dr. Thomas Schäpers
Phone: +49 2461 61-2668
Fax: +49 2461 61-2940
email: th.schaepers@fz-juelich.de