Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 6: Transport: Quantum Coherence and Quantum Information Systems - Theory I

TT 6.7: Talk

Monday, March 31, 2014, 12:30–12:45, HSZ 204

Resonant versus dispersive gates in circuit quantum electrodynamics — •Per Liebermann and Frank Wilhelm — Universität des Saarlandes, Saarbrücken, Germany

Implementation of accurate two-qubit gates in the presence of decoherence is one of the main tasks of building a quantum computer. In this work we describe two superconducting qubits coupled via a resonator and perform a controlled-Z operation on them. Being able to control the qubits’ transition frequencies, we compare the resonant and dispersive gate implementation of CZ [1,2], where in the latter case qubit-qubit interaction is mediated by virtual photons. We make use of the Lindblad master equation to study different regimes of resonator relaxation and qubit decoherence and their impact on gate fidelity. Finally, we discuss the tradeoff between the higher speed of the resonant gate versus the protection from the Purcell effect in the dispersive gate, which we show to usually be in favor of resonant gates.
A. Blais et al., Phys. Rev. A 75, 032329 (2007)
D.J. Egger and F.K. Wilhelm, Supercond. Sci. Technol. 27 (2014)