Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 42: Optical Properties of Quantum dots: Theory and Simulation
HL 42.9: Talk
Thursday, February 28, 2008, 12:00–12:15, EW 201
Study of combined decoherence channels of optically controlled spin rotations in quantum dot systems — •Anna Grodecka1,2, Paweł Machnikowski2, Carsten Weber3, Andreas Knorr3, and Jens Förstner1 — 1Computational Nanophotonics Group, University Paderborn, Germany — 2Institute of Physics, Wrocław University of Technology, Poland — 3Nonlinear Optics and Quantum Electronics, Technical University Berlin, Germany
It has been recently proposed [1] that coupling to a trion state may lead to a Raman transition between the two Zeeman-split spin states in a quantum dot, which allows for optical coherent control of a spin. However, the question arises whether the intrinsic features of the system may lead to decoherence which counteracts the ideal coherent control.
In this work, we study the combined decoherence channels resulting from the influence of phonon and photon reservoirs, as well as from the imperfections of the evolution of an optical spin control based on an off-resonant coupling of the spin states to a trion state in a doped semiconductor quantum dot. Using a perturbative theory describing the open system evolution we calculate the total error of the spin-based quantum gate. The optimal conditions for coherent operations are indicated and possible ways of reducing the decoherence are discussed [2].
1. P. Chen, C. Piermarocchi, L. J. Sham, D. Gammon, and D. G. Steel, Phys. Rev. B 69, 075320 (2004).
2. A. Grodecka, C. Weber, P. Machnikowski, and A. Knorr, Phys. Rev. B 76, 205305 (2007).