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Journal of Physics A Mathematical and General

Critical properties of the Ashkin-Teller model from the mean-field renormalisation group approach

J. A. Plascak, F. C. Sá Barreto

Published Aug 1, 1986• 35 citations
Publisher

Abstract

By using small size clusters, which carry all the basic symmetries of the Ashkin-Teller model, the authors obtain within the mean-field renormalisation group approach the complete phase diagram of the model. Estimates of the thermal critical exponent are also obtained.
DOI
10.1088/0305-4470/19/11/027

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The (1+1)-dimensional Ashkin-Teller model is studied by the renormalisation group method and by the finite lattice extrapolation technique. The possible phases and their boundaries in an extended space of couplings are determined from the degeneracy structure of the low-lying levels in the thermodynamic limit. The critical behaviour is investigated for ferromagnetic couplings using increasing block sizes in the renormalisation transformation. The line of fixed points and its bifurcation at the Potts fixed point is studied.
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