Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 41: Matter at Low Temperature: Quantum Liquids, Bose-Einstein-Condensates, Ultra-cold Atoms

TT 41.18: Vortrag

Donnerstag, 26. März 2009, 18:45–19:00, HSZ 105

Phase Diagram of Polar Molecules with Three-Body Interactions — •Lars Bonnes, Stefan Wessel, and Hans-Peter Büchler — Institut für theoretische Physik III, Universität Stuttgart

Motivated by a recent proposal on using polar molecules in optical lattices driven by microwave fields to induce strong three-body interactions (H. P. Büchler et al., Nature Physics 3, 726 (2007)), we analyze the quantum phase diagram of the boson Hubbard model with dominant nearest neighbor three-body repulsions using quantum Monte Carlo simulations. In particular, we consider the case of a honeycomb-lattice in the hard-core limit. In contrast to previously studied cases of the chain and the square lattice, three-body repulsions on the honeycomb lattice exhibit clear characteristics of strongly frustrated interactions, giving rise to macroscopically degenerate classical regions and quantum state selections via order-by-disorder phenomena. We discuss the nature of the emerging insulating phases at several unconventional lattice fillings, and compare to effective low-energy descriptions, such as in terms of quantum dimer models.