Quantum gravitational fluctuations and the semi-classical limit

TL;DR

This paper explores quantum gravitational fluctuations beyond the semi-classical approximation, showing they can influence the classical limit and potentially prevent singularities in cosmology and gravitational collapse.

Contribution

It introduces additional terms representing quantum gravitational fluctuations into the semi-classical framework, advancing the understanding of quantum effects in gravity.

Findings

Quantum fluctuations can alter the semi-classical limit.

These fluctuations may prevent classical singularities.

The semi-classical approximation becomes more delicate with quantum fluctuations.

Abstract

An attempt is made to go beyond the standard semi-classical approximation for gravity in the Born-Oppenheimer decomposition of the wave-function in minisuperspace. New terms are included which correspond to quantum gravitational fluctuations on the background metric. Their existence renders the definition of the semi-classical limit rather delicate and can lead to the avoidance of the singularities the classical theory predicts in cosmology and in the gravitational collapse of compact objects.