CALCULATION OF NUMERICAL MICROCANONICAL ENSEMBLE METHOD ON 2D STATISTICAL-MODELS

In our earlier work, we proposed a new microcanonical ensemble method and showed that the numerical results of this method are correct in 1D models. In this paper, the numerical data in 2D models are presented. One of our calculations is concentrated on fermionic models, because fermionic models behave quite differently from bosonic models when the dimension is larger than two (there may be boson-fermion duality in 1 D). Our results come out to be consistent with exact values. To our kn owledge, there is no other numerical methods which can present reliabl e calculation on fermionic models with large lattice, especially when the temperature is low. In addition to the test on fermionic models, w e also show our results on quantum 2D XY model. We calculate longitudi nal spin-spin correlation, specific heat, vortex density and vortex pa ir density. These results agree with the calculations by other methods . The data of vortex density and vortex pair density seem to. display directly the unbinding of vortices and antivortices.