Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 8: Correlated Electrons: Spin Systems and Itinerant Magnets 1
TT 8.10: Vortrag
Montag, 25. Februar 2008, 16:30–16:45, H 0104
Numerical investigation of the quantum dimer model on a diamond lattice — •Olga Sikora1, Frank Pollmann1, Nic Shannon2, Karlo Penc3, and Peter Fulde1 — 1Max Planck Institute for the Physics of Complex Systems, Noethnitzer Str. 38, 01187 Dresden, Germany — 2H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1 TL, UK — 3Research Institute for Solid State Physics and Optics, H-1525 Budapest, P.O.B. 49, Hungary
Quantum dimer models (QDMs) are of great interest in the study of systems with frustrated spin or charge degrees of freedom. On bipartite lattices these QDMs can be mapped onto a U(1)-gauge theory, with a liquid-like ground state and fractional excitations. However in two dimensions, these excitations are confined, except at the Rokhsar-Kivelson (RK) point, a quantum critical point occurring for one specific ratio of parameters. Recently, it has been suggested that in the QDM on a 3D diamond lattice, a U(1) liquid is not confined to a single point, but extends for a finite range of parameters bordering the RK point.
We have used Green's Function Monte Carlo (GFMC) and Variational Monte Carlo simulations to test this conjecture numerically. Our preliminary GFMC calculations suggest that the confining potential for fractional excitations vanishes in a large region of the parameter space, confirming the existence of an extended liquid phase.