Transfer-Matrix Calculations of the Spin 1/2 Antiferromagnetic XXZ Model on the 4 x2 Triangular Lattice Using the Fractal Decomposition

Abstract

The fractal decomposition of exponential operators proposed by Suzuki, which is a new category of the generalized Trotter decomposition valid up to higher orders, is examined with transfer-matrix calculations of the spin 1/2 antiferromagnetic XXZ model on the 4 x 2 triangular lattice. The dependence of correction terms on the Trotter number and temperature are studied. This depen­ dence confirms rapid convergence of the fractal decomposition. The negative-sign problem arising in quantum Monte Carlo simulations is also discussed ·from the present new point of view.