Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 23: TR: Quantum Coherence and Quantum Information Systems 2
TT 23.1: Talk
Wednesday, March 24, 2010, 14:00–14:15, H18
Dynamics of strongly coupled Qubit-TLF systems — •Clemens Müller1,2, Jared H. Cole3,2, Jürgen Lisenfeld4, Pavel Bushev4, Alexander Shnirman1,2, and Alexey V. Ustinov4,2 — 1Institut für Theorie der Kondensierten Materie, KIT, Karlsruhe, Germany — 2DFG-Center for Functional Nanostructures (CFN), Karlsruhe, Germany — 3Institut für Theoretische Festkörperphysik, KIT, Karlsruhe, Germany — 4Physikalisches Institut, KIT, Karlsruhe, Germany
Spectroscopy of superconducting qubits often shows clear signatures of avoided crossings, indicating the presence of intrinsic two-level fluctuators (TLFs). Experiments are usually performed when the qubit is well detuned from resonance with these TLF since they are considered a source of decoherence. Alternatively one can tune the qubit in resonance with a TLF and observe the dynamics of the coupled multi-level system. We show results on rabi-spectroscopy in and near resonance with an individual TLF in the regime where both the coupling between qubit and TLF as well as the Rabi-frequency is strong. In addition we report on driving the system with high power, when the effect of higher levels in the qubit become important. This may pave the way towards understanding the microscopic nature of the TLFs.