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Renormalization Group Improved Optimized Perturbation Theory: Revisiting the Mass Gap of the O(2N) Gross-Neveu Model
Kneur J.-L., Neveu A.
Physical Review D 81, 12 (2010) 125012 - http://hal.archives-ouvertes.fr/hal-00494268
Physique/Physique des Hautes Energies - Théorie
Physique/Physique des Hautes Energies - Phénoménologie
Renormalization Group Improved Optimized Perturbation Theory: Revisiting the Mass Gap of the O(2N) Gross-Neveu Model
Jean-Loïc Kneur ()1, André Neveu ()1
1 :  LPTA - Laboratoire de Physique Théorique et Astroparticules
http://www.lpta.in2p3.fr/
CNRS : UMR5207 – IN2P3 – Université Montpellier II - Sciences et techniques
Bât 13- 1er Et. - CC 070 Place Eugène Bataillon 34095 MONTPELLIER CEDEX 5
France
We introduce an extension of a variationally optimized perturbation method, by combining it with renormalization group properties in a straightforward (perturbative) form. This leads to a very transparent and efficient procedure, with a clear improvement of the non-perturbative results with respect to previous similar variational approaches. This is illustrated here by deriving optimized results for the mass gap of the O(2N) Gross-Neveu model, compared with the exactly know results for arbitrary N. At large N, the exact result is reproduced already at the very first order of the modified perturbation using this procedure. For arbitrary values of N, using the original perturbative information only known at two-loop order, we obtain a controllable percent accuracy or less, for any N value, as compared with the exactly known result for the mass gap from the thermodynamical Bethe Ansatz. The procedure is very general and can be extended straightforwardly to any renormalizable Lagrangian model, being systematically improvable provided that a knowledge of enough perturbative orders of the relevant quantities is available.
Anglais
04/05/2010

Physical Review D (Phys. Rev. D)
Publisher American Physical Society
ISSN 1550-7998 (eISSN : 1550-2368)
internationale
Articles dans des revues avec comité de lecture
17/06/2010
81
12
125012

18 pages, 1 figure
LPTA:10-043

Lien vers le texte intégral : 
http://fr.arXiv.org/abs/1004.4834