2009MNRAS.396..946B

It is generally expected that quantum gravity theory should yield the model of a space-time foam at short distances leading to Lorentz-invariance violation (LIV) manifested e.g. by energy-dependent modification of the standard relativistic dispersion relation. One direction of research, pursued intensively, is to measure the energy-dependent time-of-arrival delays in photons emitted by astrophysical sources located at cosmological distances. This is tempered, however, by our ignorance of intrinsic emission delays in different energy channels.

In this paper we discuss a test based on gravitational lensing. Monitoring time delays between images obtained in different energy channels, for example optical (low-energy) and TeV photons, may reveal extra delays due to the distorted dispersion relation typical in LIV theories, a test that is free from the systematics inherent in other settings.