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2PI effective action and gauge invariance problems

M. E. Carrington·G. Kunstatter·H. Zaraket
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Abstract

The problem of maintaining gauge invariance when truncating the two particle irreducible (2PI) effective action has been studied recently by several authors. Here we give a simple and very general derivation of the gauge dependence identities for the off-shell 2PI effective action. We consider the case where the gauge is fixed by an arbitrary function of the quantum gauge field, subject only to the restriction that the Faddeev-Popov matrix is invertable. We also study the background field gauge. We address the role that these identies play in solving gauge invariance problems associated with physical quantities calculated using a truncated on-shell 2PI effective action.

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M. E. Carrington, G. Kunstatter, H. Zaraket. 2005-05-11. 2PI effective action and gauge invariance problems. https://doi.org/10.1140/epjc%2Fs2005-02277-x

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