Zr. Yang, SOLVABLE ISING-MODEL ON SIERPINSKI CARPETS - THE PARTITION-FUNCTION, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 49(3), 1994, pp. 2457-2460
With a special Sierpinski carpet (SC), the Ising model is exactly solv
ed by a combinatorial approach and graph technique. The rigorous parti
tion function and free energy are obtained and the phase transition is
investigated. We argue that the existence of a phase transition stron
gly depends on the order of ramification of the SC. Our method is exte
nded to deal with other lattices.