Comparison of QG-Induced Dispersion with Standard Physics Effects

Abstract

One of the predictions of quantum gravity phenomenology is that, in situations where Planck-scale physics and the notion of a quantum spacetime are relevant, field propagation will be described by a modified set of laws. Descriptions of the underlying mechanism differ from model to model, but a general feature is that electromagnetic waves will have non-trivial dispersion relations. A physical phenomenon that offers the possibility of experimentally testing these ideas in the foreseeable future is the propagation of high-energy gamma rays from GRB's at cosmological distances. With the observation of non-standard dispersion relations within experimental reach, it is thus important to find out whether there are competing effects that could either mask or be mistaken for this one. In this letter, we consider possible effects from standard physics, due to electromagnetic interactions, classical as well as quantum, and coupling to classical geometry. Our results indicate that, for currently observed gamma-ray energies and estimates of cosmological parameter values, those effects are much smaller than the quantum gravity one if the latter is first-order in the energy; some corrections are comparable in magnitude with the second-order quantum gravity ones, but they have a very different energy dependence.

8 pages; Version to be published in CQG as a letter; Includes some new comments and references, but no changes in the results

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Cited by in corpus (6)

• Quantum Spacetime Phenomenology
• Constraints on Lorentz Invariance Violation from Fermi-Large Area Telescope Observations of Gamma-Ray Bursts
• Dark Matter Constraints from a Cosmic Index of Refraction
• Testing Planck scale gravity with accelerators
• Constraining new fundamental physics with multiwavelength astrometry
• Planck-scale gravity test at PETRA -- Letter of Intent