Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 7: Cold Atomic Gases
TT 7.10: Vortrag
Montag, 7. März 2016, 12:45–13:00, H18
Frustrated magnetism with soft-shoulder potentials and cluster liquids — •Tao Ying1,2, Marcello Dalmonte3,4, and Guido Pupillo1 — 1IPCMS (UMR 7504) and ISIS (UMR 7006), University of Strasbourg and CNRS, 67000 Strasbourg, France — 2Institute for Theoretical Solid State Physics, RWTH Aachen University, 52056 Aachen, Germany — 3Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria — 4Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
Cold bosonic atoms in optical lattices with finite-range soft-shoulder potentials (i.e., soft-core potentials with an additional hard-core onsite interaction) can cause cluster formation, which provides a natural source of frustration that leads to infinite ground state degeneracies, and hence to exotic quantum phenomena. Using quantum Monte Carlo simulations, we study the Bose-Hubbard model on a square lattice with soft-shoulder potentials V of finite-range rc=2√2a, where a denotes the lattice spacing. Upon increasing V/t, the model exhibits a superfluid to cluster liquid transition, where in the latter phase, the correlation functions such as the momentum distribution shows a distinct shape compared to the normal liquid. We also study the nature of the correlations and winding number histograms at the quantum critical point.