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arXiv · 1902.09901

Critical points of coupled vector-Ising systems. Exact results

Gesualdo Delfino·Noel Lamsen
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Abstract

We show that scale invariant scattering theory allows to exactly determine the critical points of two-dimensional systems with coupled $O(N)$ and Ising order pameters. The results are obtained for $N$ continuous and include criticality of loop gas type. In particular, for $N=1$ we exhibit three critical lines intersecting at the Berezinskii-Kosterlitz-Thouless transition point of the Gaussian model and related to the $Z_4$ symmetry of the isotropic Ashkin-Teller model. For $N=2$ we classify the critical points that can arise in the XY-Ising model and provide exact answers about the critical exponents of the fully frustrated XY model.

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Gesualdo Delfino, Noel Lamsen. 2019-02-26. Critical points of coupled vector-Ising systems. Exact results. https://doi.org/10.1088/1751-8121/ab3055

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