In summary, the Fermi observations probe quantum gravity and set the best bounds on Lorentz violation we have so far. In the parametrization popular among the Lorentz-violating self-described "quantum gravity theorists", the typical scale where the Lorentz violation starts to be big must be above 1/10 of the Planck mass. Everything below this gigantic mass scale has been proven to respect the Lorentz symmetry, if you wish. People who have been promoting a complete denial of special relativity - in the form of various loop quantum gravities, doubly or deformed special relativities, dynamical triangulations, and all this stuff have been idiots, just like I have always emphasized
#36
MTd2
Gold Member
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It could be well be that the relation is almost a Heaviside function! :)
Taming nonlocality in theories with deformed Poincare symmetry
Giovanni Amelino-Camelia, Marco Matassa, Flavio Mercati, Giacomo Rosati
(Submitted on 10 Jun 2010)
We here advocate a perspective on recent research investigating possible Planck-scale deformations of relativistic symmetries, which is centered on Einstein's characterization of spacetime points, given exclusively in terms of physical events. We provide the first ever explicit construction of worldlines governed by a Planck-scale deformation of Poincar\'e symmetry. And we show that the emerging physical picture allows a description that is faithful to Einstein's program, but forces the renunciation of the idealization of the coincidence of events. We use this to expose the limitations of the pre-Einsteinian description of spacetime points adopted in some recent related studies. In particular we find that the estimate of nonlocal effects reported in the recent Physical Review Letters 104, 140402 (2010) is incorrect by 29 orders of magnitude.*****