Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 44: Transport: Quantum Coherence and Quantum Information

TT 44.9: Talk

Thursday, March 26, 2009, 16:15–16:30, HSZ 304

Relaxation of Josephson qubits due to strong coupling to two-level systems — •Clemens Müller and Alexander Shnirman — Institut für Theorie der Kondensierten Materie, Universität Karlsruhe, 76128 Karlsruhe, Germany

Naturally formed two-level systems (TLS) present in the oxide layer of nm-sized Josephson junctions pose a strong complication in the design of superconducting qubits. Recently an experiment used the coherent dynamics of a strongly coupled TLS to demonstrate its uses as a naturally formed quantum memory [1]. We calculate the effect of strongly coupled TLS on the relaxation rate Γ₁ of the qubit. In addition to providing results for single TLS we analyse the effects of an ensemble of TLS.

[1] M. Neeley at al, Nature Physics 4, 523 (2008)