Dresden 2006 – scientific programme
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TT: Tiefe Temperaturen
TT 32: Transport: Quantum Coherence and Quantum Information Systems - Part 2
TT 32.2: Talk
Thursday, March 30, 2006, 14:15–14:30, HSZ 304
Inductive effects in tunable capacitive coupling of charge qubits — •Carsten Hutter and Alexander Shnirman — Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D–76128 Karlsruhe, Germany
Recently, tunable capacitive [1] and inductive [2] coupling of Josephson charge
and flux qubits have been proposed. Here, we concentrate on coupling of charge
qubits via a Josephson junction, which provides a tunable effective capacitance.
For this situation, it was suggested [3], that the capacitive coupling could be
accompanied by an inductive one.
We clarify the situation by considering the limits where the Josephson energy of the
coupling junction is much greater (much smaller) than its charging energy,
EJ≫ Ec (EJ≪ Ec).
In the limit EJ≪ Ec, the inductive coupling appears as a small correction
to the capacitive one. It will however play a role at the point, where the
capacitive coupling vanishes.
In the limit EJ≫ Ec, we find that the inductive coupling dominates
over the capacitive one.
[1] D. V. Averin and C. Bruder, Phys. Rev. Lett. 91, 057003 (2003).
[2] B. L. T. Plourde et al., Phys. Rev. B 70, 140501(R) (2004).
[3] A. Zorin, cond-mat/0510435 (2005)