Düsseldorf 2007 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 41: Quanteninformation (Konzepte II)
Q 41.3: Vortrag
Mittwoch, 21. März 2007, 14:30–14:45, 5L
Time-continuous quantum state estimation — •Artur Scherer1, Lajos Diosi2, Thomas Konrad3, and Jürgen Audretsch1 — 1Fachbereich Physik, Universität Konstanz, Fach M 674, 78457 Konstanz, Germany — 2Research Institute for Particle and Nuclear Physics, 1525 Budapest 114, P.O.Box 49, Hungary — 3School of Pure and Applied Physics, University of KwaZulu-Natal, Durban 4000, South Africa
Controlling single quantum systems is an important issue in quantum information processing technology. Recent experimental advancements have made feasible time-continuous weakly disturbing quantum measurements on a single system. New perspectives of quantum feed-back control have raised an immediate related task: the time-continuous estimation and real-time determination of a quantum state. We discuss the time-continuous quantum state estimation problem and present a new non-linear stochastic master equation that governs the time-evolution of the estimated quantum state. Its differential evolution corresponds to the infinitesimal updates that depend on the time-continuous measurement of the true quantum state. The new stochastic master equation couples to the two standard stochastic differential equations of time-continuous quantum measurement. We prove that the calculated estimate almost always converges to the true state. We demonstrate this convergence by a numerically simulated evolution of the true and the estimated wave function of a particle in a double-well potential.