Modelos de mecânica estatística exatamente solúveis em duas dimensões / Exactly solvable models of statistical mechanics in two dimensions

AUTOR(ES)
DATA DE PUBLICAÇÃO

1984

RESUMO

We study some spin and vertex systems which are exactly solvable in two dimensions. The exact solubility is connected to the existence of non trivial solutions of the factorization equations which allow us to determine the free energy in the thermodynamic limit. We introduce and solve by the inverse scattering method, a ten vertex model with two and three states on the links. We get the phase diagram of the system and show that it exhibits a first order phase transition. Analysing a free fermion eight vertex model, we propose a new functional relation which permit us to get the free energy per vertex. We also show that this system is equivalent to the Ising model in a Union Jack lattice. We present a method to solve spin models on triangular lattices from the known solution of the same model on square lattices. The method applies whenever the model involves first neighbours interactions and satisfies the star triangle relation. We extend to the triangular lattice the self dual solutions of Fateev and Zamolodchikov for Z(N) invariant spin systems. We also analyse the conjectures made before for the critical Potts model on a Kagomé lattice. Based on symmetry and on the collapses of this lattice we conjecture an expression for their critical line.

ASSUNTO(S)

relação triângulo-estrela modelos exatamente solúveis star-triangle relation yang-baxter equations equações de yang-baxtor exactly solved models

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