Latent Heat Calculation of the 3D q=3, 4, and 5 Potts models by Tensor Product Variational Approach

Three-dimensional (3D) $q$-state Potts models ($q$=3, 4, and 5) are studied by the tensor product variational approach (TPVA), which is a recently developed variational method for 3D classical lattice models. The variational state is given by a two-dimensional (2D) product of local factors, and is improved by way of self-consistent calculations assisted by the corner transfer matrix renormalization group (CTMRG). It should be noted that no a priori condition is imposed for the local factor. Transition temperatures and latent heats are calculated from the observations of thermodynamic functions in both ordered and disordered phases.