Functional flows in QED and the modified Ward-Takahashi identity

Abstract

In the functional renormalisation group approach to gauge theory, the Ward-Takahashi identity is modified due to the presence of an infrared cutoff term. It take the most accessible form for the Wilsonian effective action. In the present work we solve these identities, partially, for the Wilson effective action of QED. In particular, we compute the longitudinal part of the photon two point vertex function as a momentum- dependent function in the presence of the cutoff k. The resultant Wilsonian effective action carries form factors that originate from the modified Ward-Takahashi identity. We show how this result carries over to the one-particle-irreducible effective action.

15 pages

References in corpus (5)

• Exact evolution equation for the effective potential
• Chiral symmetry breaking in continuum QCD
• On the construction of QED using ERG
• Equivalence of Wilson Actions
• Fixed point structure of the Abelian Higgs model

Cited by in corpus (9)

• The nonperturbative functional renormalization group and its applications
• Quantum gravity: a fluctuating point of view
• Non-perturbative finite-temperature Yang-Mills theory
• BRST in the Exact RG
• Renormalization group flows of the N-component Abelian Higgs model
• BRST invariant RG flows
• Gradient Flow Exact Renormalization Group for Scalar Quantum Electrodynamics
• Background Effective Action with Nonlinear Massive Gauge Fixing
• Functional Renormalization Group Flows and Gauge Consistency in QED