title: Role of quantum fluctuations in the hexatic phase of cold polar molecules.
abstract: Two-dimensional crystals melt via an intermediate hexatic phase, which is characterized by an anomalous scaling of spatial and orientational correlation functions and the absence of an attraction between dislocations. We propose a protocol to study the effect of quantum fluctuations on the nature of this phase with a model system of strongly correlated ultracold polar molecules. Dislocations can be located in experiment from local energy differences which induce internal stark shifts in the molecules. We present a criterion to identify the hexatic phase from the statistics of the end points of topological defect strings and find a hexatic phase, which is dominated by quantum fluctuations, between the crystal and superfluid phases.
authors.affiliation: Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, 6020 Innsbruck, Austria and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lechner
authors.affiliation: Institute for Theoretical Physics III, University of Stuttgart, D-70550 Stuttgart, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Büchler
authors.affiliation: Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, 6020 Innsbruck, Austria and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Zoller