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arXiv · hep-ph/9409459

Kosterlitz-Thouless Phase Transition In The Two Dimensional Linear Sigma Model

M. Gr"ater·C. Wetterich
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Abstract

We investigate the O(N) symmetric linear $σ$-model in two dimensions by means of an exact nonperturbative evolution equation. The perturbative infrared divergences are absent in this formulation. We use a simple approximative solution of the flow equation which corresponds to a derivative expansion for the effective action. For N=2 this gives a good picture of the Kosterlitz-Thouless phase transition.

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M. Gr"ater, C. Wetterich. 1994-09-30. Kosterlitz-Thouless Phase Transition In The Two Dimensional Linear Sigma Model. https://doi.org/10.1103/physrevlett.75.378

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