2003/04/15 by Graham M Shore · 1 citation
Physics and Astronomy · #gr-qc
paper · pdf · doi:10.1080/00107510310001617106
published as Contemp.Phys. 44 (2003) 503-521 · 28 pages, 5 figures. Review article commissioned by `Contemporary Physics'
arxiv created 2003/04/15 · arxiv updated 2009/11/30
In quantum theory, the curved spacetime of Einstein's general theory of relativity acts as a dispersive optical medium for the propagation of light. Gravitational rainbows and birefringence replace the classical picture of light rays mapping out the null geodesics of curved spacetime. Even more remarkably, \it superluminal propagation becomes a real possibility, raising the question of whether it is possible to send signals into the past. In this article, we review recent developments in the quantum theory of light propagation in general relativity and discuss whether superluminal light is compatible with causality.