Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 7: Quantum Coherence and Quantum Information Systems II

TT 7.6: Vortrag

Montag, 26. März 2007, 15:15–15:30, H20

Quantum Telegraph Noise — •Benjamin Abel and Florian Marquardt — Physics Department, Center for NanoScience, and Arnold Sommerfeld Center for Theoretical Physics, München

We analyze the effect of quantum telegraph noise, produced by a single electronic defect level, on the decoherence of a charge qubit. In contrast to earlier works, [1], [2], [3], we describe the full time-evolution of the coherence factor even at short and intermediate times. In striking contrast to the well-known case of decoherence by a bath of harmonic oscillators, the coherence factor displays oscillations as a function of time and other parameters. We analyze these in detail using a numerical evaluation of the exact solution for the density matrix of the qubit.

[1] Y. Makhlin, A. Shnirman, Phys. Rev. Lett. 92, 178301 (2004).

[2] Alex Grishin, Igor V. Yurkevich, and Igor V. Lerner, Phys. Rev. B 72, 060509(R) (2005)

[3] Galperin, Y. M., Altshuler, B. L., and Shantsev, D. V., Phys. Rev. Lett. 96 097009 (2006)