Diplom-Physiker Sven Welack

Reduced Density Matrix Approach to the Laser-Assisted Electron Transport in Molecular Wires

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Kurzfassung in Englisch

The electron transport through a molecular wire under the influence of an
external laser field is studied using a reduced density matrix formalism.
The full system is partitioned into the relevant part, i.e. the wire, electron
reservoirs and a phonon bath. An earlier second-order perturbation theory approach of Meier and Tannor for
bosonic environments which employs a numerical decomposition of the spectral
density is used to describe the coupling to the phonon bath and is extended
to deal with the electron transfer between the reservoirs and the molecular wire.
Furthermore, from the resulting time-nonlocal (TNL) scheme a time-local (TL)
approach can be determined. Both are employed to propagate the reduced density
operator in time for an arbitrary time-dependent system Hamiltonian which
incorporates the laser field non-perturbatively.
Within the TL formulation, one can extract a current operator for the open quantum system.
This enables a more general formulation of the problem which is necessary to
employ an optimal control algorithm for open quantum systems in order to
compute optimal control fields for time-distributed target states, e.g. current patterns. Thus, we take
a fundamental step towards optimal control in molecular electronics. Numerical examples of the population dynamics, laser controlled current, TNL vs. TL and optimal control fields are presented to demonstrate the diverse applicability of
the derived formalism.

weitere Metadaten

electron transport
molecular wires
reduced density matrix
time-dependent transport
SWD SchlagworteDichtematrix
SWD SchlagworteElektronentransport
SWD SchlagworteQuantenmechanik
DDC Klassifikation530
HochschuleTU Chemnitz
FakultätFakultät für Naturwissenschaften
Tag d. Einreichung (bei der Fakultät)30.11.2005
Veröffentlichungsdatum (online)07.04.2006
persistente URNurn:nbn:de:swb:ch1-200600571

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