Stellar Black Holes and the Origin of Cosmic Acceleration

TL;DR

This paper proposes that black holes in a modified gravity theory could explain cosmic acceleration, linking local black hole physics to the universe's large-scale expansion and making testable predictions for dark energy evolution.

Contribution

It introduces a UV-IR coupling in gravitational aether theory and shows how black holes could drive cosmic acceleration consistent with observations.

Findings

Black holes exhibit UV-IR coupling in this theory.

Accelerating solutions match current dark energy observations.

Predicted dark energy evolution can be tested with future probes.

Abstract

The discovery of cosmic acceleration has presented a unique challenge for cosmologists. As observational cosmology forges ahead, theorists have struggled to make sense of a standard model that requires extreme fine tuning. This challenge is known as the cosmological constant problem. The theory of gravitational aether is an alternative to general relativity that does not suffer from this fine-tuning problem, as it decouples the quantum field theory vacuum from geometry, while remaining consistent with other tests of gravity. In this paper, we study static black hole solutions in this theory and show that it manifests a UV-IR coupling: Aether couples the spacetime metric close to the black hole horizon, to metric at infinity. We then show that using the Trans-Planckian ansatz (as a quantum gravity effect) close to the black hole horizon, leads to an accelerating cosmological solution, far from the horizon. Interestingly, this acceleration matches current observations for stellar mass black holes. Based on our current understanding of the black hole accretion history in the Universe, we then make a prediction for how the effective dark energy density should evolve with redshift, which can be tested with future dark energy probes.