Quantum Gravity@Radboud publishes the first contributions to the "Handbook of Quantum Gravity" (Eds. C. Bambi, L. Modesto and I.L. Shapiro, Springer Singapore, expected in 2023)
The "Handbook of Quantum Gravity" seeks to give a broad survey of quantum gravity research in the broadest sense with many scientists contributing to this effort. Today the first contribution by the Quantum Gravity@Radboud-group has been made public. The text is available at https://arxiv.org/abs/2210.16072
Comments are welcome.
Form Factors in Asymptotically Safe Quantum Gravity
Asymptotic Safety implies that observables including scattering amplitudes remain finite at the highest energy scales. Traditionally, this feature is connected to an interacting fixed point of the Wilsonian renormalization group that provides the high-energy completion of the theory. In this article, we discuss a different facet of Asymptotic Safety, reviewing its imprint on the quantum effective action. We start with a concise introduction to the form factor framework for gravity and gravity-matter systems, before giving an encyclopaedic overview of gravity-mediated scattering amplitudes derived from the quantum effective action. We illustrate the use of the framework based on form factors appearing in the context of quadratic gravity and Asymptotic Safety, before making the connections to positivity bounds derived for low-energy effective field theories and the computation of form factors from first principles. We conclude that the form factor framework offers a unique, unifying perspective on quantum gravity. In particular, it plays a pivotal role in determining the phenomenological consequences of Asymptotic Safety at the level of observables.