Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 13: Transport: Poster Session
TT 13.40: Poster
Montag, 26. März 2012, 15:00–19:00, Poster B
Decoherence of Josephson junction qubits due to surface spins — •Pablo Schad1, Boris Narozhny1, Alexander Shnirman1,2, and Gerd Schön3 — 1Institut für Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — 2DFG Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — 3Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany
Spins on surfaces of superconductors are considered to be responsible for the 1/f flux noise in SQUIDs and Josephson qubits [1,2,3,4,5].
In recent experiments the spin contribution to the inductance of superconducting wires was measured [6]. This inductance describes the response to a current, which polarizes spins by creating magnetic fields on the surface.
In particular, low frequency fluctuations of the complex inductance were observed with roughly a 1/f noise spectrum.
We provide an analysis of inductance noise in analogy to the theory of "noise of noise" and analyze some microscopic models that could explain these experiments. Special attention is paid to RKKY interaction.
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