Connected Green function approach to symmetry breaking in Φ {1+1/4}-theory
Abstract
Using the cluster expansions for n-point Green functions we derive a closed set of dynamical equations of motion for connected equal-time Green functions by neglecting all connected functions higher than 4 th order for the λΦ 4-theory in 1 + 1 dimensions. We apply the equations to the investigation of spontaneous symmetry breaking, i.e. to the evaluation of the effective potential at temperature T=0. Within our momentum space discretization we obtain a second order phase transition (in agreement with the Simon-Griffith theorem) and a critical coupling of λ crit /4 m 2=2.446 as compared to a first order phase transition and λ crit /4 m 2=2.568 from the Gaussian effective potential approach.
- Publication:
-
Zeitschrift fur Physik A Hadrons and Nuclei
- Pub Date:
- September 1995
- DOI:
- 10.1007/BF01292336
- arXiv:
- arXiv:hep-ph/9408355
- Bibcode:
- 1995ZPhyA.353..301H
- Keywords:
-
- 11.30.Qc;
- 11.90.+t;
- High Energy Physics - Phenomenology
- E-Print:
- 25 Revtex pages, 5 figures available via fpt from the directory ugi-94-11 of ftp@theorie.physik.uni-giessen.de as one postscript file (there was a bug in our calculations, all numerical results and figures have changed significantly), ugi-94-11