Fakeons, Microcausality And The Classical Limit Of Quantum Gravity

TL;DR

This paper explores fakeons in quantum gravity, highlighting their role in microcausality violation, renormalizability, and modifications to classical gravity equations, with potential experimental implications.

Contribution

It introduces the concept of fake particles in quantum gravity, demonstrating their impact on microcausality, unitarity, and the classical limit, proposing a new consistent quantum gravity theory.

Findings

Fakeons cause microcausality violation that persists in the classical limit.

A spin-2 fakeon with a scalar field renders quantum gravity renormalizable and unitary.

Modified field equations include future-dependent terms, resembling an average of future influences.

Abstract

We elaborate on the idea of fake particle and study its physical consequences. When a theory contains fakeons, the true classical limit is determined by the quantization and a subsequent process of "classicization". One of the major predictions due to the fake particles is the violation of microcausality, which survives the classical limit. This fact gives hope to detect the violation experimentally. A fakeon of spin 2, together with a scalar field, is able to make quantum gravity renormalizable while preserving unitarity. We claim that the theory of quantum gravity emerging from this construction is the right one. By means of the classicization, we work out the corrections to the field equations of general relativity. We show that the finalized equations have, in simple terms, the form $\langle F\rangle =ma$, where $\langle F\rangle $ is an average that includes a little bit of "future".