Comments on the entropic gravity proposal

TL;DR

This paper tests the entropic gravity hypothesis by deriving gravitational forces near black holes and stars, finding that the entropic explanation fails in general, thus challenging the validity of the entropic gravity proposal.

Contribution

It provides explicit calculations of gravitational forces in various black hole and stellar scenarios, demonstrating limitations of the entropic gravity model.

Findings

Entropic force derivation matches black hole horizons

Fails to reproduce gravity for arbitrary spherical stars

Supports skepticism about entropic gravity as a universal explanation

Abstract

Explicit tests are presented of the conjectured entropic origin of the gravitational force. The gravitational force on a test particle in the vicinity of the horizon of a large Schwarzschild black hole in arbitrary spacetime dimensions is obtained as entropic force. The same conclusion can be reached for the cases of a large electrically charged black hole and a large slowly rotating Kerr black hole. The generalization along the same lines to a test mass in the field of an arbitrary spherical star is also studied and found not to be possible. Our results thus reinforce the argument that the entropic gravity proposal cannot account for the gravitational force in generic situations.