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HL: Fachverband Halbleiterphysik

HL 12: Quantum dots and wires: Optical properties I

HL 12.4: Vortrag

Montag, 26. März 2007, 15:30–15:45, H17

Phonon dephasing in optical control of a single spin in a quantum dot — •Anna Grodecka^1,2, Carsten Weber¹, Paweł Machnikowski², and Andreas Knorr¹ — ¹Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — ²Institute of Physics, Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, 50-370 Wrocław, Poland

Unique and designable properties of quantum dots together with the availability of fast optical control methods indicate that these systems may be considered as attractive candidates for use as qubits. It is advantageous to store the logical values in spin states of an electron in a quantum dot (due to the long decoherence time) and perform the operations using optical coupling to the charge degrees of freedom (short switching time). However, quantum dots are embedded in a surrounding crystal and the confined carriers interact with phonons, which leads to a loss of coherence.

Within a density matrix approach, we consider the carrier-phonon dynamics in the optical control of a single spin in a quantum dot. Using perturbative methods we study the phonon-induced decoherence accompanying a single qubit gate: an arbitrary rotation between two selected electron spin states performed via spin-flip Raman transitions and virtual excitation of a trion state.