Renormalisation-Group Specific Heat of the Square Lattice Potts Ferromagnet

摘要

The free and internal energies and specific heat of the q-state Potts ferromagnet are discussed. A real space renormalisation group approach is presented which recovers a considerable amount of exact particular results for all dimensionalities (hypercubic lattices). The square lattice case is calculated in detail by using self-dual clusters (which provide the exact critical point for all q). Comparison with Onsager results (q=2) is satisfactory; the general tendencies for q different 2 (1<=q<=4) are exhibited, and the bond percolation limit (q approaches 1) is worked out with some detail. (Atomindex citation 15:004027)