Journal article

Publication year: 2007

Pages: 155-164

Journal: Physics Letters B

Volume number: 646

Issue number: 4

ISSN: 0370-2693

eISSN: 1873-2445

Open access status: Green

DOI Link: https://doi.org/10.1016/j.physletb.2007.01.028

Publisher: Elsevier

Abstract: 
In thermal field theory selfconsistent (Phi-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. (c) 2007 Elsevier B.V. All rights reserved.

Harvard Citation style: Leupold, S. (2007) Selfconsistent approximations, symmetries and choice of representation, Physics Letters B, 646(4), pp. 155-164. https://doi.org/10.1016/j.physletb.2007.01.028

APA Citation style: Leupold, S. (2007). Selfconsistent approximations, symmetries and choice of representation. Physics Letters B. 646(4), 155-164. https://doi.org/10.1016/j.physletb.2007.01.028