Over the past 20 years, there has been considerable interest in the possibility of quantum-gravity-induced in vacuo dispersion, the idea that spacetime itself might behave essentially like a dispersive medium for particle propagation. A violation of Lorentz Invariance (LIV) of this kind can lead to an observable effect on the time of flight of VHE particles from cosmic origin. First, I'll summarize past studies that looked for LIV effects in gamma-ray observations made with ground-based Cherenkov telescopes. Then, I'll show some interesting early evidence that some of the neutrinos seen by the IceCube observatory might be GRB neutrinos whose travel times are affected by spacetime's quantum properties, making them move more slowly than the speed of light.
Elia Bertoldo, Clara Fernández, Giada Caneva