Article ID Journal Published Year Pages File Type
10725150 Physics Letters B 2007 10 Pages PDF
Abstract
In thermal field theory selfconsistent (Φ-derivable) approximations are used to improve (resum) propagators at the level of two-particle irreducible diagrams. At the same time vertices are treated at the perturbative level. Therefore such approximations typically violate the Ward identities connected to internal symmetries. Examples are presented how such violations can be tamed by a proper choice of representation for the fields which describe the system under consideration. These examples cover the issue of massless Goldstone bosons in the linear sigma model and the Nambu-Jona-Lasinio model and the problem of current conservation in theories with massive vector mesons.
Related Topics
Physical Sciences and Engineering Physics and Astronomy Nuclear and High Energy Physics
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