MONTE-CARLO CALCULATIONS ON THE SPIN-3/2 HEISENBERG ANTIFERROMAGNETIC CHAINS

An efficient projector Monte Carlo method has been used to calculate the energies of the ground state and the first excited state of the spin-3/2 Heisenberg antiferromagnetic chains with linear sizes up to N = 32. We have found that the ground state energy per site converges to its thermodynamic limit value as fast as 1/N2 and the thermodynamic limit value is e0 = -2.8248. All of our results show that the energy gap tends to zero as N --> infinity, which is consistent with the rigorous proof.