K. Krebs et S. Sandow, MATRIX PRODUCT EIGENSTATES FOR ONE-DIMENSIONAL STOCHASTIC-MODELS AND QUANTUM SPIN CHAINS, Journal of physics. A, mathematical and general, 30(9), 1997, pp. 3165-3173
We show that all zero-energy eigenstates of an arbitrary m-state quant
um spin chain Hamiltonian with nearest-neighbour interaction in the bu
lk and single site boundary terms, which can also describe the dynamic
s of stochastic models, can be written as matrix product states. This
means that the weights in these states can be expressed as expectation
values in a Fock representation of an algebra generated by 2m operato
rs fulfilling m(2) quadratic relations which are defined by the Hamilt
onian.