  In this paper, we propose a novel quantum paramagnetic state in
two-dimensional antiferromagnets: the spontaneously trimer state, which is
constructed by the trimers of spins. Each trimer is a singlet state formed by
three neighboring spins with SU(3) symmetry. A frustrated spin-1 Heisenberg
model in the kagome lattice is investigated. By analogy to the pseudo-potential
approach in the fractional quantum Hall effect (FQHE), we find that the trimer
state provides a perfect description for the exact ground state of this model.
Other interesting properties, such as the local excitations as well as
magnetization plateaus have also been investigated. It is shown that this novel
state would deepen our understanding of the nature of the many-body
entanglement in the two-dimensional strong correlated systems.
