  We show that correlated hopping of triplets, which is often the dominant
source of kinetic energy in dimer-based frustrated quantum magnets, produces a
remarkably strong tendency to form supersolid phases in a magnetic field. These
phases are characterized by simultaneous modulation and ordering of the
longitudinal and transverse magnetization respectively. Using Quantum Monte
Carlo and a semiclassical approach for an effective hard-core boson model with
nearest-neighbor repulsion on a square lattice, we prove in particular that a
supersolid phase can exist even if the repulsion is not strong enough to
stabilize an insulating phase at half-filling. Experimental implications for
frustrated quantum antiferromagnets in a magnetic field at zero and finite
temperature are discussed.
