  Ring-exchange interactions have been proposed as a possible mechanism for a
Bose-liquid phase at zero temperature, a phase that is compressible with no
superfluidity. Using the Stochastic Green Function algorithm (SGF), we study
the effect of these interactions for bosons on a two-dimensional triangular
lattice. We show that the supersolid phase, that is known to exist in the
ground state for a wide range of densities, is rapidly destroyed as the
ring-exchange interactions are turned on. We establish the ground-state phase
diagram of the system, which is characterized by the absence of the expected
Bose-liquid phase.
