title: Efficient quantum-state estimation by continuous weak measurement and dynamical control.
abstract: We demonstrate a fast, robust, and nondestructive protocol for quantum-state estimation based on continuous weak measurement in the presence of a controlled dynamical evolution. Our experiment uses optically probed atomic spins as a test bed and successfully reconstructs a range of trial states with fidelities of approximately 90%. The procedure holds promise as a practical diagnostic tool for the study of complex quantum dynamics, the testing of quantum hardware, and as a starting point for new types of quantum feedback control.
authors.affiliation: College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Greg A
authors.initials: GA
authors.lastname: Smith
authors.forename: Andrew
authors.initials: A
authors.lastname: Silberfarb
authors.forename: Ivan H
authors.initials: IH
authors.lastname: Deutsch
authors.forename: Poul S
authors.initials: PS
authors.lastname: Jessen