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TMF, 2006 Volume 146, Number 3, Pages 365–384 (Mi tmf2041)

This article is cited in 3 papers

Epsilon-expansion in the $N$-component $\varphi^4$ model

M. D. Missarov, R. G. Stepanov

Kazan State University

Abstract: The formalism of projection Hamiltonians is applied to the $N$-component $O(N)$-invariant $\varphi^4$ model in the Euclidean and $p$-adic spaces. We use two versions of the $\varepsilon$-expansion (with $\varepsilon=4-d$ and $\varepsilon=\alpha-3d/2$ where $\alpha$ is the renormalization group parameter) and evaluate the critical indices $\nu$ and $\eta$ up to the second order of the perturbation theory. The results for the $(4-d)$-expansion then coincide with the known results obtained via the quantum-field renormalization-group methods. Our calculations give evidence that in dimension three, both expansions describe the same non-Gaussian fixed point of the renormalization group.

Keywords: $\varepsilon$-expansion, renormalization group, Euclidean models, $p$-adic models, perturbation theory, critical indices.

Received: 07.04.2005
Revised: 06.06.2005

DOI: 10.4213/tmf2041


 English version:
Theoretical and Mathematical Physics, 2006, 146:3, 304–320

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© Steklov Math. Inst. of RAS, 2025