A perspective on Quantum Gravity Phenomenology

TL;DR

This paper reviews quantum gravity phenomenology, emphasizing the importance of focused analyses on Lorentz symmetry tests using cosmic rays and gamma-ray bursts, and highlights future prospects with ultra-high-energy neutrino observatories.

Contribution

It advocates for targeted phenomenological tests of quantum spacetime features, cautioning against overly broad analyses, and discusses upcoming experimental opportunities with neutrino observatories.

Findings

Lorentz symmetry tests are crucial for quantum gravity phenomenology.

Current analyses like Crab nebula synchrotron radiation have limitations.

Future neutrino observatories can probe high-energy regimes for quantum spacetime effects.

Abstract

I give a brief overview of some Quantum-Gravity-Phenomenology research lines, focusing on studies of cosmic rays and gamma-ray bursts that concern the fate of Lorentz symmetry in quantum spacetime. I also stress that the most valuable phenomenological analyses should not mix too many conjectured new features of quantum spacetime, and from this perspective it appears that it should be difficult to obtain reliable guidance on the quantum-gravity problem from the analysis of synchrotron radiation from the Crab nebula and from the analysis of phase coherence of light from extragalactic sources. Forthcoming observatories of ultra-high-energy neutrinos should provide several opportunities for clean tests of some simple hypothesis for the short-distance structure of spacetime. In particular, these neutrino studies, and some related cosmic-ray studies, should provide access to the regime $E>\sqrt{m E_p}$.