Real-space renormalization group approach to the 2D antiferromagnetic Heisenberg model

We apply real-space RG techniques to study the quantum two-dimensional antiferromagnetic Heisenberg model for arbitrary values of the spin S on a square lattice. We introduce a 5-block truncation scheme which yields complete analytical results for renormalizing spin factors, ground state energy and non-zero staggered magnetization. Our RG-flow equations show that the 2D model remains massless ∀S. We propose that the valence bonds forming the ground state of the 2D-AF Heisenberg model on a square lattice rotate under the effect of the antiferromagnetic background.