Choose timezone
Your profile timezone:
Description
The light cones traced out by real photon propagation in QFT in curved spacetime do not necessarily coincide with the geometric light cone structure of the spacetime if the strong equivalence principle (SEP) is violated. SEP-violating interactions are known to be induced by quantum effects even in QED in a background curved spacetime and apparently give rise to superluminal photon propagation. In this talk, we review the essential ideas of vacuum polarisation induced superluminal propagation, describe explicit examples in black hole and gravitational wave backgrounds, and discuss the issue of dispersion which is critical to the implications for causality.