Reliability of the optimized perturbation theory in the 0-dimensional $O(N)$ scalar field model
| Autor: | Rosa, Derick S. [UNESP], Farias, R. L. S., Ramos, Rudnei O. |
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| Přispěvatelé: | Universidade Estadual Paulista (Unesp), Universidade Federal de Sergipe (UFS), Kent State Univ, Universidade do Estado do Rio de Janeiro (UERJ) |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Web of Science Repositório Institucional da UNESP Universidade Estadual Paulista (UNESP) instacron:UNESP |
| Popis: | We address the reliability of the Optimized Perturbation Theory (OPT) in the context of the 0-dimensional $O(N)$ scalar field model. The effective potential, the self-energy and the 1PI four-point Green's function for the model are computed using different optimization schemes and the results contrasted to the exact results for the model. Our results are also compared to those obtained with the $1/N$-expansion and with those from ordinary perturbation theory. The OPT results are shown to be stable even at large couplings and to have better convergence properties than the ones produced in the $1/N$-expansion. It is also shown that the principle of minimal sensitive optimization procedure used in conjunction with the OPT method tends to always produce better results, in particular when applied directly to the self-energy. 38 pages, 13 figures, v2 Physica A version |
| Databáze: | OpenAIRE |
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