Berlin 2014 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 58: Quantum information: Concepts and methods IV

Q 58.1: Talk

Friday, March 21, 2014, 10:30–10:45, Kinosaal

Dynamical decoupling with stochastic unitary pulses — •József Zsolt Bernád, Holger Frydrych, and Gernot Alber — Institut für Angewandte Physik, Technische Universität Darmstadt, D-64289 Germany

Dynamical decoupling is a powerful method to increase coherence times of quantum states by applying regular controlled unitary pulses to a quantum system. We propose a stochastic model to describe imperfections in the applied pulses and discuss the impact of this kind of error on different decoupling schemes. In the limit of continuous control we derive a stochastic evolution for the density matrix. In the context of this modified time evolution we discuss the possibilities of protecting the time evolution of a subsystem against the rest of the system. In the case of finite dimensional Hilbert spaces we derive an inequality, which quantifies the relationship between the number of pulses and the effectiveness of the decoupling procedure. We demonstrate our model for both finite and countably infinite dimensional Hilbert spaces and relate to ongoing experimental works.