Loop Quantum Gravity Phenomenology: Linking Loops to Observational Physics

TL;DR

This review explores how loop quantum gravity could produce observable effects in cosmology and particle physics, discussing models, potential tests, and the challenges in linking theory with observations.

Contribution

It provides a comprehensive overview of phenomenological models linked to loop quantum gravity and discusses their potential observational signatures and current challenges.

Findings

Loop quantum gravity may lead to testable modifications in cosmological and particle physics observations.

There is ongoing debate about whether local Lorentz invariance is preserved or violated in these models.

Current observations are being refined to better test predictions from loop quantum gravity.

Abstract

Research during the last decade demonstrates that effects originating on the Planck scale are currently being tested in multiple observational contexts. In this review we discuss quantum gravity phenomenological models and their possible links to loop quantum gravity. Particle frameworks, including kinematic models, broken and deformed Poincar\'e symmetry, non-commutative geometry, relative locality and generalized uncertainty principle, and field theory frameworks, including Lorentz violating operators in effective field theory and non-commutative field theory, are discussed. The arguments relating loop quantum gravity to models with modified dispersion relations are reviewed, as well as, arguments supporting the preservation of local Lorentz invariance. The phenomenology related to loop quantum cosmology is briefly reviewed, with a focus on possible effects that might be tested in the near future. As the discussion makes clear, there remains much interesting work to do in establishing the connection between the fundamental theory of loop quantum gravity and these specific phenomenological models, in determining observational consequences of the characteristic aspects of loop quantum gravity, and in further refining current observations. Open problems related to these developments are highlighted. characteristic aspects of loop quantum gravity, and in further refining current observations. Open problems related to these developments are highlighted.