  Many-body entangled quantum states studied in condensed matter physics can be
primary resources for quantum information, allowing any quantum computation to
be realized using measurements alone, on the state. Such a universal state
would be remarkably valuable, if only it were thermodynamically stable and
experimentally accessible, by virtue of being the unique ground state of a
physically reasonable Hamiltonian made of two-body, nearest neighbor
interactions. We introduce such a state, composed of six-state particles on a
hexagonal lattice, and describe a general method for analyzing its properties
based on its projected entangled pair state representation.
