J. Phys. I France
Volume 2, Numéro 11, November 1992
Page(s) 2011 - 2018
DOI: 10.1051/jp1:1992261
J. Phys. I France 2 (1992) 2011-2018

An explicit formula for the interface tension of the 2D Potts model

Christian Borgs1 and Wolfhard Janke2

1  Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, D-1000 Berlin 33, Germany
2  Höchstleistungsrechenzentrum, Forschungszentrum Jülich, Postfach 1913, D-5170 Jülich, Germany

(Received 4 September 1992, accepted 8 September 1992)

We consider the exact correlation length calculations for the two-dimensional Potts model at the transition point $\beta_{\rm t}$ by Klümper, Schadschneider and Zittartz, and by Buffenoir and Wallon. We argue that the correlation length calculated by the latter authors is the correlation length in the disordered phase and then combine their result with duality and the assumption of complete wetting to give an explicit formula for the order-disorder interface tension $\sigma_{\rm od}$ of this model. The result is used to clarify a controversy stemming from different numerical simulations of $\sigma_{\rm od}$.

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