ACAD SINICA,INST HIGH ENERGY PHYS,BEIJING 100039,PEOPLES R CHINA
We investigate the phase structure of the d-dimensional q-state Potts models on lattice by the variational cumulant expansion (VCE) approach, we calculate the internal energy and specific heat for this model. Specially we give the results for 2-dimensional q=4,5,6 states Ports models. A comparison with Monte Carlo (MC) data is also presented. Our formalism can give the results for Ports models in any dimensionality d and any states q straightforwardly.