Loop quantum gravity and light propagation

摘要: Within loop quantum gravity we construct a coarse-grained approximation for the Einstein-Maxwell theory that yields effective Maxwell equations in flat spacetime comprising Planck scale corrections. The corresponding Hamiltonian is defined as expectation value of electromagnetic term constraint, regularized manner Thiemann, with respect to would-be semiclassical state. resulting energy dispersion relations entail corrections those spacetime. Both helicity dependent contribution Gambini and Pullin and, parameter our approximation, Ellis co-workers are recovered. electric-magnetic asymmetry regularization procedure nonlinearities only magnetic sector which briefly discussed. Observations cosmological gamma ray bursts might eventually lead needed accuracy study some these effects.