Monte Carlo renormalization-group study of the rectangular Ising ferromagnet: Universality and a fixed line

The renormalization-group description of the anisotropic two-dimensional Ising model has been investigated with the use of Monte Carlo renormalization-group methods. We have been able to demonstrate the existence of a fixed line with universal critical exponents, in contrast to the nonuniversality of the Baxter fixed line. The possibility of a model with any given anisotropy being described by any point on the fixed line is demonstrated by explicit calculations. © 1984 The American Physical Society.