Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 29: Poster Session: Quantum Information Systems, Quantum Coherence (jointly with SAMOP)

TT 29.3: Poster

Dienstag, 15. März 2011, 18:00–21:00, P1

Decoherence of Josephson junction qubits due to surface spins — •Pablo Schad¹, Boris Narozhny¹, Alexander Shnirman^1,2, 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 currently believed 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 well known theory of "noise of noise" and analyze some microscopic models that could explain these experiments.
F. C. Wellstood et al., Appl. Phys. Lett. 50, 772 (1987).
S. Sendelbach et al., Phys. Rev. Lett. 100, 227006 (2008).
H. Bluhm et al., Phys. Rev. Lett. 103, 026805 (2009).
R. H. Koch et al., Phys. Rev. Lett. 98, 267003 (2007).
L. Faoro and L. B. Ioffe, Phys. Rev. Lett. 100, 227005 (2008).
S. Sendelbach et al., Phys. Rev. Lett. 100, 227006 (2008).