Probing strongly correlated states of ultracold atoms in optical lattices [Elektronische Ressource] / Simon Fölling

Probing Strongly Correlated States of UltracoldAtoms in Optical LatticesDissertationzur Erlangung des Grades"Doktorder Naturwissenschaften"am Fachbereich Physikder Johannes Gutenberg-Universitätin MainzSimon Föllinggeboren in MünsterMainz, den 16.10.2008D77ArchiMeD Mainz (online) VersionDatum der mündlichen Prüfung: 16. Oktober 2008iiAbstractThis thesis describes experiments which investigate ultracold atom ensembles in anoptical lattice. Such quantum gases are powerful models for solid state physics. Sev-eral novel methods are demonstrated that probe the special properties of stronglycorrelated states in lattice potentials. Of these, quantum noise spectroscopy revealsspatial correlations in such states, which are hidden when using the usual methods ofprobing atomic gases. Another spectroscopic technique makes it possible to demon-strate the existence of a shell structure of regions with constant densities. Such co-existing phases separated by sharp boundaries had been theoretically predicted forthe Mott insulating state. The tunneling processes in the optical lattice in the stronglycorrelated regime are probed by preparing the ensemble in an optical superlatticepotential. This allows the time-resolved observation of the tunneling dynamics, andmakes it possible to directly identify correlated tunneling processes.