2012/06/16 by Takahiro Ohgoe, Takafumi Suzuki, Naoki Kawashima · 2 citations
Physics and Astronomy · #cond-mat.quant-gas
paper · pdf · doi:10.1103/physrevb.86.054520
published as Phys. Rev. B 86, 054520 (2012)
arxiv created 2012/06/16 · arxiv updated 2012/08/29
We investigate the ground-state phase diagram of the soft-core Bose-Hubbard model with the nearest-neighbor repulsion on a square lattice by using an unbiased quantum Monte Carlo method. In contrast to the previous study[P. Sengupta \it et. al., Phys. Rev. Lett. \bf 94, 207202 (2005)], we present the ground-state phase diagrams up to large hopping parameters. As a result, in addition to the known supersolid above half-filling, we find supersolid even below and at half-filling for large hopping parameters. Furthermore, for the strong nearest-neighbor repulsion, we show that the supersolid phase occupies a remarkably broad region in the phase diagram. The results are in qualitative agreement with that obtained by the Gutzwiller mean-field approximation[M. Iskin, Phys. Rev. A \bf 83, 051606(R) (2011) and T. Kimura, Phys. Rev. A \bf 84, 063630 (2011)].