Coherent-Anomaly Method Applied to the Quantum Heisenberg Model

K.G. Chakraborty

James L. Monroe

Kazuhiko Minami, Masuo Suzuki

Nobuyasu Ito, Masuo Suzuki

The coherent-anomaly method (CAM) is applied to the Heisenberg model to test the applicability of the CAM for quantum spin systems. The Weiss, Bethe and constant coupling approximations are tried for the Heisenberg model on the simple cubic lattice and estimate the critical exponents of the susceptibility and spontaneous magnetization using the CAM. The results show that the CAM is also powerful for quantum spin systems. The detailed results of the Bethe approximation of the spin-1/2 isotropic Heisenberg model are presented.

K.G. Chakraborty

I. Golhirsch, Evgeny Levich, Victor Yakhot