Quantum gravity phenomenology at the dawn of the multi-messenger era -- A review

TL;DR

This review discusses how multi-messenger astronomy enables the search for quantum gravity effects through high-energy cosmic particles, emphasizing interdisciplinary efforts to detect Planck-scale signatures.

Contribution

It provides a comprehensive overview of the interdisciplinary approaches needed to identify quantum gravity phenomenology in multi-messenger astrophysics.

Findings

Multi-messenger data enhances sensitivity to quantum gravity effects.

Cosmological distances amplify tiny quantum gravity signals.

Interdisciplinary collaboration is crucial for progress in this field.

Abstract

The exploration of the universe has recently entered a new era thanks to the multi-messenger paradigm, characterized by a continuous increase in the quantity and quality of experimental data that is obtained by the detection of the various cosmic messengers (photons, neutrinos, cosmic rays and gravitational waves) from numerous origins. They give us information about their sources in the universe and the properties of the intergalactic medium. Moreover, multi-messenger astronomy opens up the possibility to search for phenomenological signatures of quantum gravity. On the one hand, the most energetic events allow us to test our physical theories at energy regimes which are not directly accessible in accelerators; on the other hand, tiny effects in the propagation of very high energy particles could be amplified by cosmological distances. After decades of merely theoretical investigations, the possibility of obtaining phenomenological indications of Planck-scale effects is a revolutionary step in the quest for a quantum theory of gravity, but it requires cooperation between different communities of physicists (both theoretical and experimental). This review is aimed at promoting this cooperation by giving a state-of-the art account of the interdisciplinary expertise that is needed in the effective search of quantum gravity footprints in the production, propagation and detection of cosmic messengers.