Velocity of signal in attractive potential and propagation of light in gravitational field

Abstract

The propagation of a massless field in attractive and repulsive potentials is considered. It is shown that though the group velocity in such potentials can be larger than one, the wave front propagates with the speed of light. A larger-than-one group velocity leads only to a strong deformation of the wave packet. The results obtained are applied to the light propagation in a gravitational field. An erroneous assertion concerning the last problem, recently made in the literature, is refuted.

6 pages, latex twice

References in corpus (2)

• Superluminal Velocity of Photons in a Gravitational Background
• Analytical properties of scattering amplitudes in one-dimensional quantum theory

Cited by in corpus (4)

• The Causal Structure of QED in Curved Spacetime: Analyticity and the Refractive Index
• Faster than Light Photons in Gravitational Fields II - Dispersion and Vacuum Polarisation
• Resolving Puzzles of Massive Gravity with and without violation of Lorentz symmetry
• Linearized Lorentz-Violating Gravity and Discriminant Locus in the Moduli Space of Mass Terms