Non perturbative renormalization group and momentum dependence of n-point functions (II)
| dc.creator | Blaizot, Jean-Paul | |
| dc.creator | Mendez-Galain, Ramon | |
| dc.creator | Wschebor, Nicolas | |
| dc.date | 2006-03-21 | |
| dc.date.accessioned | 2026-07-07T10:46:15Z | |
| dc.date.available | 2026-07-07T10:46:15Z | |
| dc.description | In a companion paper (hep-th/0512317), we have presented an approximation scheme to solve the Non Perturbative Renormalization Group equations that allows the calculation of the $n$-point functions for arbitrary values of the external momenta. The method was applied in its leading order to the calculation of the self-energy of the O($N$) model in the critical regime. The purpose of the present paper is to extend this study to the next-to-leading order of the approximation scheme. This involves the calculation of the 4-point function at leading order, where new features arise, related to the occurrence of exceptional configurations of momenta in the flow equations. These require a special treatment, inviting us to improve the straightforward iteration scheme that we originally proposed. The final result for the self-energy at next-to-leading order exhibits a remarkable improvement as compared to the leading order calculation. This is demonstrated by the calculation of the shift $ΔT_c$, caused by weak interactions, in the temperature of Bose-Einstein condensation. This quantity depends on the self-energy at all momentum scales and can be used as a benchmark of the approximation. The improved next-to-leading order calculation of the self-energy presented in this paper leads to excellent agreement with lattice data and is within 4% of the exact large $N$ result. | |
| dc.description | 35 pages, 11 figures | |
| dc.identifier | https://arxiv.org/abs/hep-th/0603163 | |
| dc.identifier | http://arxiv.org/abs/hep-th/0603163 | |
| dc.identifier | Phys.Rev.E74:051117,2006 | |
| dc.identifier | doi:10.1103/PhysRevE.74.051117 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/183168 | |
| dc.subject | High Energy Physics - Theory | |
| dc.subject | Other Condensed Matter | |
| dc.title | Non perturbative renormalization group and momentum dependence of n-point functions (II) | |
| dc.type | text |