Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 55: Poster Session: Superconductivity 2

TT 55.8: Poster

Mittwoch, 22. März 2017, 15:00–19:00, P2-OG3

Superconducting qubit as a detector of atomic tunneling systems toggling on time scales spanning six orders of magnitude — •Saskia Meißner, Arnold Seiler, Jürgen Lisenfeld, Alexey V. Ustinov, and Georg Weiss — Physikalisches Institut, Karlsruher Institut für Technologie

AlO_x is a common material used for the production of Josephson junctions in superconducting qubits. It is known that the mostly disordered thin-film AlO_x contains atomic tunneling systems. Coherent tunneling systems couple strongly with their electric dipole moment to the qubit, giving rise to level repulsion in its spectrum. Slowly fluctuating tunneling systems are also observable if they are located close to the coherent ones and cause a local distortion of their potentials. Thus they are visible by telegraphic noise of the energy splitting of the coherent tunneling systems which can be measured on time scales from hours to minutes. The high-resolution single-photon spectroscopy measurement protocoll for the detection of coherent tunneling systems also allows us to determine fluctuation rates on a time scale of milliseconds by a special statistical analysis of the measured qubit states.