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Longitudinal and transverse Greens functions in phi^4 model below and near the critical point

J. Kaupuzs
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Abstract

We have extended our method of grouping of Feynman diagrams (GFD theory) to study the transverse (G_t) and longitudinal (G_l) Greens functions in phi^4 model below the critical point (T T_c. The long-wave limit k->0 has been studied at T T_c as well as with a non-perturbative renormalization group (RG) analysis provided in our paper. It is confirmed also by Monte Carlo simulation. The exponents, as well as the ratio bM^2/a^2 (where M is magnetization, a and b are the amplitudes of G_t and G_l at k->0) are universal. The results of the perturbative RG method are reproduced by formally setting lambda_t=2. Nevertheless, we disprove the conventional statement that lambda_t=2 is the exact result.

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J. Kaupuzs. 2004-06-29. Longitudinal and transverse Greens functions in phi^4 model below and near the critical point. https://arxiv.org/abs/cond-mat/0202416

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