title: Quantum nondemolition measurements and state preparation in quantum gases by light detection.
abstract: We consider light scattering from ultracold quantum gas in optical lattices into a cavity. The measurement of photons leaking out of the cavity enables a quantum nondemolition access to various atomic variables. The time resolved light detection projects the motional state to various atom-number squeezed and macroscopic superposition states that strongly depend on the geometry. Modifications of the atomic and light properties at a single quantum trajectory are demonstrated. The quantum structure of final states can be revealed by further observations of the same sample.
authors.affiliation: Institut für Theoretische Physik, Universität Innsbruck, Innsbruck, Austria. Igor.Mekhov@uibk.ac.at
authors.forename: Igor B
authors.initials: IB
authors.lastname: Mekhov
authors.forename: Helmut
authors.initials: H
authors.lastname: Ritsch