Dresden 2011 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 50: Quantum Effects: Entanglement and Decoherence

Q 50.5: Talk

Thursday, March 17, 2011, 11:30–11:45, SCH A01

Task-dependent control of open quantum systems — •Jens Clausen — Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria

We consider the evolution of an open quantum system to second order in its coupling to a bath and describe the effect of a controlled time-dependence of the system Hamiltonian on a chosen function of the system state at a fixed time. This function defines a task quantity to be optimized such as fidelity, purity, or entanglement. If the time-dependence of the system Hamiltonian is fast enough to be comparable or shorter than the response-time of the bath, then the resulting non-Markovian dynamics allows to optimize the chosen task quantity. This implies on the one hand protecting a desired unitary system evolution from bath-induced decoherence but on the other hand also allows to use the system-bath coupling to realize a desired non-unitary effect on the system. Joint work with G. Bensky and G. Kurizki.