Heidelberg 1999 – wissenschaftliches Programm
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SYQI: Symposium Quanteninformationsverarbeitung
SYQI 4: Quanteninformationsverarbeitung IV (Poster)
SYQI 4.2: Poster
Dienstag, 16. März 1999, 16:30–18:30, PHB
Supermolecular porphyrin complex as a Q-bit carrier — •D. Kilin — Institut für Physik, Technische Universität, D-09107 Chemnitz
We consider the possibility to store a Q-bit in the supermolecular complex of the sequentially linked free-base porphyrin H2P, zinc porphyrin ZnP, and quinone Q. The time evolution of the complex is calculated with a density matrix method both for the excitation regime induced by one or several optical pulses and for the regime of relaxation induced by coupling to a heat bath. It is shown that the quick dephasing of the vibrational states does not allow to store some information in coherent superpositions of them, despite of the relative simplicity of their creation. On the other hand, the excitation created on H2P decays with charge transfer to Q by the superexchange reaction channel. The value of the non-diagonal density matrix elements that corresponds to this transfer allows to determine whether the system still contains coherent information. The lifetime of non-diagonal elements is taken as a limit of Q-bit existence. In addition, we have estimated the chances to control this charge transfer from H2P to Q by the excitation of the intermediate block ZnP.