The Repulsive Effect of Covariant Effective Quantum Gravity

TL;DR

This paper demonstrates that quantum effects in a covariant effective quantum gravity model can cause gravity to become repulsive at the Planck scale, challenging the classical view of gravity as purely attractive.

Contribution

It provides an analytical study showing that quantum corrections can induce a repulsive gravitational effect near black holes at the Planck scale.

Findings

Quantum effects cause gravity to become repulsive at the Planck scale.

Trajectories with turning points exhibit repulsive behavior.

Quantum corrections modify classical gravitational interactions.

Abstract

In General Relativity, gravity around a black hole is universally regarded as an attractive force. However, quantum effects may significantly alter this classical picture and thus affect the dynamics of test particles. In this work, we investigate geodesic motion in a recently proposed covariant effective quantum black hole model, the ZLMY type I model in \href{https://journals.aps.org/prd/abstract/10.1103/PhysRevD.111.L081504}{[Phys.Rev.D 111 (2025) 8, L081504]}. Our analytical study reveals that, at the Planck scale, gravity can exhibit a repulsive character, most notably in trajectories involving turning points. These findings suggest that quantum corrections could fundamentally modify our conventional understanding of gravitational interactions in certain regimes.