Reference data for phase diagrams of triangular and hexagonal bosonic lattices
Institut für Physik, Carl von Ossietzky Universität - D-26111 Oldenburg, Germany
Accepted: 30 June 2010
We investigate systems of bosonic particles at zero temperature in triangular and hexagonal optical lattice potentials in the framework of the Bose-Hubbard model. Employing the process-chain approach, we obtain accurate values for the boundaries between the Mott insulating phase and the superfluid phase. These results can serve as reference data for both other approximation schemes and upcoming experiments. Since arbitrary integer filling factors g are amenable to our technique, we are able to monitor the behavior of the critical hopping parameters with increasing filling. We also demonstrate that the g-dependence of these exact parameters is described almost perfectly by a scaling relation inferred from the mean-field approximation.
PACS: 03.75.Lm – Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations / 64.70.Tg – Quantum phase transitions / 67.85.Hj – Bose-Einstein condensates in optical potentials
© EPLA, 2010