4-point vertices from the 2PI and 4PI Effective Actions
High Energy Physics - Phenomenology
2014-01-29 v1
Abstract
We consider a symmetric scalar theory with quartic coupling in 2- and 3-dimensions and compare the self-consistent 4-point vertex obtained from the 4PI effective action with the Bethe-Salpeter 4-vertex from 2PI effective action. At zero external momenta the two vertices agree well with each other when the coupling strength is small, but differences between them become more and more pronounced as the coupling strength is increased. We also study the momentum dependence of the two vertices and show that for certain momentum configurations they are almost identical, but differ for general momentum arguments.
Cite
@article{arxiv.1310.4352,
title = {4-point vertices from the 2PI and 4PI Effective Actions},
author = {M. E. Carrington and Wei-Jie Fu and P. Mikula and D. Pickering},
journal= {arXiv preprint arXiv:1310.4352},
year = {2014}
}
Comments
17 pages, 10 figures