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Field theoretic renormalization group for a nonlinear diffusion equation

N. V. Antonov·Juha Honkonen
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Abstract

The paper is an attempt to relate two vast areas of the applicability of the renormalization group (RG): field theoretic models and partial differential equations. It is shown that the Green function of a nonlinear diffusion equation can be viewed as a correlation function in a field-theoretic model with an ultralocal term, concentrated at a spacetime point. This field theory is shown to be multiplicatively renormalizable, so that the RG equations can be derived in a standard fashion, and the RG functions (the $β$ function and anomalous dimensions) can be calculated within a controlled approximation. A direct calculation carried out in the two-loop approximation for the nonlinearity of the form $ϕ^α$, where $α>1$ is not necessarily integer, confirms the validity and self-consistency of the approach. The explicit self-similar solution is obtained for the infrared asymptotic region, with exactly known exponents; its range of validity and relationship to previous treatments are briefly discussed.

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N. V. Antonov, Juha Honkonen. 2002-07-02. Field theoretic renormalization group for a nonlinear diffusion equation. https://doi.org/10.1103/physreve.66.046105

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