Entanglement in an SU(n) valence-bond-solid state

We investigate entanglement properties in the ground state of the open/periodic SU(n) generalized valence-bond-solid state consisting of representations of SU(n). We obtain exact expressions for the reduced density matrix of a block of contiguous spins and explicitly evaluate the von Neumann and the Rényi entropies. We discover that the Rényi entropy is independent of the parameter α in the limit of large block sizes and its value 2log n coincides with that of von Neumann entropy. We also find the direct relation between the reduced density matrix of the subsystem and edge states for the corresponding open boundary system.