Bilinear-biquadratic spin-1 rings: an SU(2)-symmetric MPS algorithm for periodic boundary conditions

An efficient algorithm for SU(2) symmetric matrix product states (MPS) with periodic boundary conditions (PBC) is proposed and implemented. It is applied to a study of the spectrum and correlation properties of the spin-1 bilinear-biquadratic Heisenberg model. We characterize the various phases of this model by the lowest states of the spectrum with angular momentum J = 0, 1, 2 for systems of up to 100 spins. Furthermore, we provide precision results for the dimerization correlator as well as the string correlator.