Higher-Derivative Quantum Gravity with Purely Virtual Particles: Renormalizability and Unitarity
Abstract
We review the formulation of quantum field theories with purely virtual particles, a new type of degrees of freedom that can mediate interactions without ever appear as external on-shell states. This property allows to solve the problem of ghosts in higher-derivative quantum gravity, leading to a renormalizable and unitary theory. The main steps for the BRST quantization of gravity are recalled and renormalizability is discussed. Then, we introduce purely virtual particles in a general quantum field theory and show the derivation of the so-called spectral identities, which are a key ingredient to prove unitarity. Finally, phenomenological consequences and predictions in inflationary cosmology are presented.
Cite
@article{arxiv.2305.12549,
title = {Higher-Derivative Quantum Gravity with Purely Virtual Particles: Renormalizability and Unitarity},
author = {Marco Piva},
journal= {arXiv preprint arXiv:2305.12549},
year = {2023}
}
Comments
article prepared for EPJ Plus, Focus Point on Higher Derivatives in Quantum Gravity: Theory, Tests, Phenomenology; Published version