Symmetry adapted finite-cluster solver for quantum Heisenberg model in two dimensions: a real-space

Abstract

We present a quantum cluster solver for the spin-S Heisenberg model on a twodimensional lattice. The formalism is based on the real-space renormalization procedure and uses the lattice point group-theoretical analysis and non-Abelian SU(2) spin symmetry technique. The exact diagonalization procedure is used twice at each renormalization group step. The method is applied to the spinhalf antiferromagnet on a square lattice, and a calculation of local observables is demonstrated. A symmetry-based truncation procedure is suggested and verified numerically © 2010 IOP Publishing Ltd.