Lecture on Quantum Gravity with Perimeter Action and Gravitational Singularities

TL;DR

This paper explores a novel perimeter-based action in quantum gravity, demonstrating its potential to eliminate singularities during stellar collapse by creating inaccessible regions behind event horizons.

Contribution

It introduces a perimeter action for quantum gravity and shows how it can prevent singularities by forming unreachable regions during star collapse.

Findings

Perimeter action suppresses singular configurations.

Unreachable regions form behind event horizons in the modified theory.

Singularities are potentially excluded from the physical description.

Abstract

Motivated by quantum-mechanical considerations we earlier suggested an alternative action for discretised quantum gravity which measures the perimeter of the space-time and has a dimension of length. It is the so called perimeter action, since it is a "square root" of the area action in gravity and has a new constant of dimension one in front. The physical reason to introduce the perimeter/linear action was to suppress singular configurations "spikes" in the quantum-mechanical integral over geometries. Here we shall consider the continuous limit of the discretised perimeter/linear action. We shall demonstrate that in the modified theory during the time evolution of a large massive star, when a star undergoes a collapse and develops an event horizon which confines the light, a smaller space-time region will be created behind the event horizon which is unreachable by test particles. These regions are located in the places where a standard theory of gravity has singularities. We are confronted here with a drastically new concept that during the time evolution of a massive star a space-time region is created which is excluded from the physical scene, being physically unreachable by test particles or observables. If this concept is accepted, then it seems plausible that the gravitational singularities are excluded from the modified theory.