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Level spectroscopy of the square-lattice three-state Potts model with a ferromagnetic next-nearest-neighbor coupling

Hiromi Otsuka·Koutaro Mori·Yutaka Okabe·Kiyohide Nomura
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Abstract

We study the square-lattice three-state Potts model with the ferromagnetic next-nearest-neighbor coupling at finite temperature. Using the level-spectroscopy method, we numerically analyze the excitation spectrum of the transfer matrices and precisely determine the global phase diagram. Then we find that, contrary to a previous result based on the finite-size scaling, the massless region continues up to the decoupling point with ${\bf Z}_3\times{\bf Z}_3$ criticality in the antiferromagnetic region. We also check the universal relations among excitation levels to provide the reliability of our result.

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Hiromi Otsuka, Koutaro Mori, Yutaka Okabe, Kiyohide Nomura. 2005-10-28. Level spectroscopy of the square-lattice three-state Potts model with a ferromagnetic next-nearest-neighbor coupling. https://doi.org/10.1103/physreve.72.046103

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