Broken symmetry phase solution of the 4 model at two-loop level of the Φ-derivable approximation

Gergely Fejos, Zsolt Szép

Research output: Contribution to journalArticle

6 Citations (Scopus)


The set of coupled equations for the self-consistent propagator and the field expectation value is solved numerically with high accuracy in Euclidean space at zero temperature and in the broken symmetry phase of the 4 model. Explicitly finite equations are derived with the adaptation of the renormalization method of van Hees and Knoll to the case of nonvanishing field expectation value. The set of renormalization conditions used in this method leads to the same set of counterterms obtained recently by Patkós and Szép in. This makes possible the direct comparison of the accurate solution of explicitly finite equations with the solution of renormalized equations containing counterterms. The numerically efficient way of solving iteratively these latter equations is obtained by deriving at each order of the iteration new counterterms which evolve during the iteration process towards the counterterms determined based on the asymptotic behavior of the converged propagator. As shown at different values of the coupling, the use of these evolving counterterms accelerates the convergence of the solution of the equations.

Original languageEnglish
Article number056001
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number5
Publication statusPublished - Sep 1 2011

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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