Bootstrapping Newton Gravity

TL;DR

This paper explores a modified Newtonian gravity model with self-interaction terms, analyzing static spherical sources and revealing behaviors near black hole formation, serving as a foundation for quantum gravity research.

Contribution

It introduces a non-linear gravitational equation incorporating self-interaction, providing insights into black hole-like configurations within a Newtonian framework.

Findings

Solutions are close to Newtonian behavior despite non-linearity.

Potential energy becomes comparable to proper mass for highly compact sources.

No Buchdahl limit exists in this classical self-interacting gravity model.

Abstract

A non-linear equation obtained by adding gravitational self-interaction terms to the Poisson equation for Newtonian gravity is here employed in order to analyse a static spherically sym- metric homogeneous compact source of given proper mass and radius and the outer vacuum. The main feature of this picture is that, although the freedom of shifting the potential by an ar- bitrary constant is of course lost, the solutions remain qualitatively very close to the Newtonian behaviour. We also notice that the negative gravitational potential energy is smaller than the proper mass for sources with small compactness, but for sources that should form black holes according to General Relativity, the gravitational potential energy becomes of the same order of magnitude of the proper mass, or even larger. Moreover, the pressure overcomes the energy density for large values of the compactness, but it remains finite for finite compactness, hence there exists no Buchdahl limit. This classical description is meant to serve as the starting point for investigating quantum features of (near) black hole configurations within the corpuscular picture of gravity in future developments.