45 research outputs found
Ground-State Phase Diagram of the Two-Dimensional Extended Bose-Hubbard Model
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)]
Diagrammatic Monte Carlo algorithm for the resonant Fermi gas
We provide a description of a diagrammatic Monte Carlo algorithm for the
resonant Fermi gas in the normal phase. Details are given on diagrammatic
framework, Monte Carlo moves, and incorporation of ultraviolet asymptotics.
Apart from the self-consistent bold scheme, we also describe a
non-self-consistent scheme, for which the ultraviolet treatment is more
involved.Comment: Revised and extended versio