Regensburg 2004 – scientific programme

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TT: Tiefe Temperaturen

TT 29: Quantenkoh
ärenz und Quanteninformationssysteme II

TT 29.9: Talk

Thursday, March 11, 2004, 16:45–17:00, H19

Influence of Pulse Shape for Josephson Junction Quantum Computation — •Carsten Hutter, Yuriy Makhlin, and Gerd Schön — Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D–76128 Karlsruhe, Germany

Recently, a controlled NOT quantum gate employing coupled charge qubits was demonstrated for the first time [1]. A pulse technique with ideally steplike pulses was used to switch the field parameters. In reality, the pulses have finite rise- and falltimes, which influence the time evolution of the qubits. While most studies on this problem consider a single qubit, we focus on the effects of the pulse shape on two coupled qubits. Analytical and numerical results are presented, and based on them a qualitative understanding of the suppression of oscillations in an earlier experiment [2] is given.

[1] T. Yamamoto et al, Nature 425, 941 (2003)

[2] Yu.A. Pashkin et al, Nature 421, 823 (2003)