Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 22: Transport: Poster Session
TT 22.17: Poster
Wednesday, February 27, 2008, 14:00–18:00, Poster B
Relaxation of Josephson qubits due to bistable fluctuators — •Clemens Müller1, Alexander Shnirman1, and Gerd Schön2 — 1Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria — 2Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany
Decoherence is a major problem for the use of superconducting Josephson qubits in quantum information processing.
Recent measurements of the relaxation time T1 of Josephson charge qubits reveal strongly nonmonotomic behavior as a function of the energy splitting (e.g. [1], [2]), the origin of which is not understood.
As a possible model we study the relaxation time T1 of a Josephson qubit coupled to an environment of bistable fluctuators (TLF) in the case that the TLFs are coupled between each other.
We show new features of T1 due to the interaction between TLFs. Two methods were used for calculation, succesive use of Golden Rule and Bloch-Redfield equations for the density matrix. The validity of the widely used Golden Rule method was studied.
[1] G. Ithier et al., Phys. Rev. B 72, 134519 (2005)
[2] O. Astafiev et al., Phys. Rev. Lett. 93, 267007 (2004)