Nonstandard optics from quantum spacetime
Abstract
We study light propagation in the picture of semiclassical spacetime that emerges in canonical quantum gravity in the loop representation. In such a picture, where spacetime exhibits a polymerlike structure at microscales, it is natural to expect departures from the perfect nondispersiveness of an ordinary vacuum. We evaluate these departures, computing the modifications to Maxwell's equations due to quantum gravity and showing that under certain circumstances nonvanishing corrections appear that depend on the helicity of propagating waves. These effects could lead to observable cosmological predictions of the discrete nature of quantum spacetime. In particular, recent observations of nondispersiveness in the spectra of gammaray bursts at various energies could be used to constrain the type of semiclassical state that describes the universe.
 Publication:

Physical Review D
 Pub Date:
 June 1999
 DOI:
 10.1103/PhysRevD.59.124021
 arXiv:
 arXiv:grqc/9809038
 Bibcode:
 1999PhRvD..59l4021G
 Keywords:

 04.60.Ds;
 98.80.Hw;
 Canonical quantization;
 General Relativity and Quantum Cosmology
 EPrint:
 4 pages, RevTeX, no figures