Loop quantum gravity and light propagation

By J. Alfaro, H. A. Morales-Técotl, L. Urrutia. 2001

280 citations recorded by the source corpus.

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

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/f5c2eb64763c9f81c24d26890fbb1ebba28a6842

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

In Statistical and Nonlinear Physics

Citations in the corpus

Loop Quantum Cosmology (2005, unknown): “This can be used to study modified dispersion relations to the extent that the result agrees with preliminary calculations performed in the full theory [115, 3, 4, 181, 182] even at a quantitative level.”
Quantum gravity with a positive cosmological constant (2002, unknown): “and other ﬁelds, these results will be reported elsewhere. It is very interesting to note that similar corrections have been derived by Gambini and Pullin[83] and by Alfaro, Morales-Tecotl and Urrutia[84] from loop quantum gravity, using a diﬀerent approach in which they study the propagation of mat”
Planck-scale modified dispersion relations and Finsler geometry (2006, background): “A succinct list includes: arguments based on string field theory tensor VEVs [10], cosmologically varying moduli scenarios [11], spacetime foam models [12], semiclassical spin-network calculations in Loop QG [13, 14], as well as non-commutative geometry studies [15, 16, 17, 18] and some brane-world ”
Modern Tests of Lorentz Invariance (2005, background): “These dispersion relations also arise in some approaches to low energy dynamics from loop quantum gravity [8, 7, 120].”
Lorentz violation at high energy: Concepts, phenomena, and astrophysical constraints (2005, background): “Aside from general issues of principle, specific hints of Lorentz violation have come from tentative calculations in various approaches to quantum gravity: string theory tensor VEVs [4], cosmologically varying moduli [5], spacetime foam [6], semiclassical spin-network calculations in Loop QG [7,8], ”
Dark matter and fundamental physics with the Cherenkov Telescope Array (2012, background): “For example there are specific predictions in some toy models [161,162] and a general parameterisation can be provided in the framework of effective field theory [159].”
Towards the QFT on curved spacetime limit of QGR: II. A concrete implementation (2002, unknown): “Pp 0264-9381/06/030909+46$30.00 © 2006 IOP Publishing Ltd Printed in the UK 909 910 H Sahlmann and T Thiemann”
An invitation to loop quantum gravity (2004, methodology): “ted[20] and has already led to some predictions for effects observable in CMB spectra[20, 21]. And there are published predictions for observable Planck scale deviations from energy momentum relations[22, 23] that imply predictions forexperimentsinprogress suchasAUGERandGLAST.For thosewhoseinterest ”
Loop Quantum Gravity (2003, background): “Various possibilities have been considered, including quantum gravitational effects on light and particle propagation at very long distances [130, 8], which could perhaps be relevant for observations in progress such as AUGER and GLAST, and others.”
THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION (2009, background): “Simulations show that LAT observations may constrain quantum gravity scenarios that give rise to an energydependent speed of light and consequent energy-dependent shifts of GRB photon arrival times (Amelino-Camelia et al. 1998; Alfaro et al. 2002).”
Quantization ambiguities in isotropic quantum geometry (2002, methodology): “However, if one does not introduce parity violating terms into the semiclassical states used for the calculation [26], the corrections start at second or fourth order [28],”