Optimum ground states for spin-3/2 chains

Abstract

We present a set of optimum ground states for a large class of spin-3/2 chains. Such global ground states are simultaneously ground states of the local Hamiltonian, i.e. the nearest neighbour interaction in the present case. They are constructed in the form of a matrix product. We find three types of phases, namely a weak antiferromagnet, a weak ferromagnet, and a dimerized antiferromagnet. The main physical properties of these phases are calculated exactly by using a transfer matrix technique, in particular magnetization and two spin correlations. Depending on the model parameters, they show a surprisingly rich structure.