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arXiv · 1306.2952

Multicritical behavior in models with two competing order parameters

Astrid Eichhorn·David Mesterházy·Michael M. Scherer
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Abstract

We employ the nonperturbative functional Renormalization Group to study models with an O(N_1)+O(N_2) symmetry. Here, different fixed points exist in three dimensions, corresponding to bicritical and tetracritical behavior induced by the competition of two order parameters. We discuss the critical behavior of the symmetry-enhanced isotropic, the decoupled and the biconical fixed point, and analyze their stability in the N_1, N_2 plane. We study the fate of non-trivial fixed points during the transition from three to four dimensions, finding evidence for a triviality problem for coupled two-scalar models in high-energy physics. We also point out the possibility of non-canonical critical exponents at semi-Gaussian fixed points and show the emergence of Goldstone modes from discrete symmetries.

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Astrid Eichhorn, David Mesterházy, Michael M. Scherer. 2013-10-26. Multicritical behavior in models with two competing order parameters. https://doi.org/10.1103/physreve.88.042141

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