We consider the gravitational correction to (electronic) vacuum polarization in the presence of a gravitational background field. The Dirac propagators for the virtual fermions are modified to include the leading gravitational correction (potential term) which corresponds to a coordinate-dependent fermion mass. The mass term is assumed to be uniform over a length scale commensurate with the virtual electron-positron pair. The on-mass shell renormalization condition ensures that the gravitational correction vanishes on the mass shell of the photon, i.e., the speed of light is unaffected by the quantum field theoretical loop correction, in full agreement with the equivalence principle. Nontrivial corrections are obtained for off-shell, virtual photons. We compare our findings to other works on generalized Lorentz transformations and combined quantum-electrodynamic gravitational corrections to the speed of light which have recently appeared in the literature.



Keywords and Phrases

Electrodynamics; Light; Light Velocity; Photons; Polarization; Quantum Electronics; Background Field; Electron-positron Pairs; Equivalence Principles; Lorentz Transformations; Quantum Electrodynamics; Renormalization; Vacuum Polarization; Virtual Photons; Gravitation

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

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© 2015 American Physical Society (APS), All rights reserved.

Publication Date

01 Feb 2015

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Physics Commons