The Lorentz invariance is a fundamental pillar of string theory. Action based on the area of \u200b\u200bthe world sheet of the string (the Nambu-Goto action) is invariant under Lorentz transformations, as one can read the first chapters of any introduction to the theory. This is a fundamental symmetry which can be broken dynamically, spontaneous, but its validity as a fundamental symmetry is at the root of the theory. However, a single photon has revolutionized the world of theoretical physics these days in a paper published by the collaboration of the telescope Fermi (formerly GLAST):
Testing Einstein's special relativity with Fermi's short hard gamma-ray burst Authors
GRB090510: Fermi GBM / LAT Collaborations
Abstract: Gamma-ray bursts (GRBs) Are The Most Powerful explosions in the universe and probe physics under extreme conditions. GRBs divided Into two classes, of short and long duration, thought to Originate from Different types of progenitor systems. The physics of gamma-ray emission Their is still Poorly Known, over 40 years after their discovery, but may be probed by their highest-energy photons. Here we report the first detection of high-energy emission from a short GRB with measured redshift, GRB 090510, using the Fermi Gamma-ray Space Telescope. We detect for the first time a GRB prompt spectrum with a significant deviation from the Band function. This can be interpreted as two distinct spectral components, which challenge the prevailing gamma-ray emission mechanism: synchrotron - synchrotron self-Compton. The detection of a 31 GeV photon during the first second sets the highest lower limit on a GRB outflow Lorentz factor, of >1200, suggesting that the outflows powering short GRBs are at least as highly relativistic as those powering long GRBs. Even more importantly, this photon sets limits on a possible linear energy dependence of the propagation speed of photons (Lorentz-invariance violation) Requiring for the first time a quantum-gravity mass scale Significantly Above the Planck mass.
This means that the photon in question meets a very accurate hf / c = p, the dispersion relation imposed by special relativity based on the Lorentz symmetry. There are theories with discrete space-times that predict deviations from this dispersion relation to the Planck scale. These theories should begin to be questioned in front of this result. Lubos Motl vehemently defends this position on her blog and discusses the experimental refutation theories like loop quantum gravity or dynamic triangulations and in turn the confirmation of string theory:
