Hunting Quantum Gravity with Analogs: the case of High Energy Particle Physics

TL;DR

This review explores how high-energy hadron scattering experiments can serve as analog systems to probe quantum gravity phenomena, highlighting the connections between particle physics and black hole thermodynamics through phenomena like the Unruh effect.

Contribution

It consolidates old and new research showing that hadron production processes can experimentally investigate quantum gravity concepts, expanding the scope beyond condensed matter analogs.

Findings

Hadron scattering processes exhibit thermal behaviors linked to quantum entanglement.

Analog systems in high-energy physics can probe quantum gravity effects.

Black hole thermodynamics concepts are reflected in hadronic matter behaviors.

Abstract

In this review we collect, for the first time in one paper, old and new results and future perspectives of the research line that uses hadron production, in high-energy scattering processes, to experimentally probe fundamental questions of quantum gravity. The key observations, that ignited the link between the two arenas, are the so-called ``color-event horizon'' of quantum chromodynamics, and the enormous (de)accelerations involved in such scattering processes: both phenomena point to the Unruh (and related Hawking) type of effects. After the first pioneering investigations of this, such research went on and on, including studies of the horizon entropy and other ``black-hole thermodynamical'' behaviors, which incidentally are also the frontier of the analog gravity research itself. It is stressed in various places here that the \textit{trait d'union} between the two phenomenologies is that in both scenarios, hadron physics and black hole physics, ``thermal'' behaviors are more easily understood not as due to real thermalization processes (sometimes just impossible, given the small number of particles involved), but rather to a stochastic/quantum entanglement nature of such temperature. Finally, other aspects, such as the self-critical organizations of hadronic matter and of black-holes, have been recently investigated. The results of those investigations are also summarized and commented upon here. As a general remark, this research line shows that indeed we can probe quantum gravity theoretical constructions with analog systems that are not confined to belong only to the condensed matter arena. This is as it must be.