Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 22: Transport: Poster Session

TT 22.16: Poster

Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B

Landau-Zener tunneling in circuit QED at finite temperatures — •David Zueco, Sigmund Kohler, and Peter Hänggi — Institut für Physik, Universität Augsburg, Augsburg, Germany

A possibility to generate single photons in a transmission line coupled to a superconducting charge qubit relies on Landau-Zener transitions between different dressed states [1,2]. Photon losses in the transmission line influence the transition probability and, moreover, limit the photon lifetime.

We study these limitations by taking the coupling of the circuit QED to its electromagnetic environment into account. The environment is integrated out within Born-Markov approximation which yields a master equation for the reduced density operator of the qubit and the transmission line. Its numerical solution provides the final occupation of both the oscillator and the spin-flip probability, as well as the conditions on the loss rate and the temperature which still allow a reliable single-photon generation.

[1] K. Saito, M. Wubs, S. Kohler, P. Hänggi and Y. Kayanuma Europhys. Lett v 76 pp. 22-28 (2006)

[2] M. Wubs, S. Kohler and P. Hänggi Physica E 40, 1872013197 (2007)