Gravitational instanton and cosmological term

TL;DR

This paper proposes a mechanism where quantum fluctuations of gravitational instantons lead to black hole nucleation, generating a cosmological term that explains inflation, reheating, and the current accelerated expansion of the Universe.

Contribution

It introduces a novel link between quantum black hole nucleation and the cosmological constant, providing a unified explanation for early inflation and late-time acceleration.

Findings

Quantum fluctuations induce black hole nucleation at finite temperature.

The resulting energy-density explains inflation and current dark energy.

The model aligns with observed cosmological evolution.

Abstract

Quantum fluctuation of unstable modes about gravitational instantons causes the instability of flat space at finite temperature, leading to the spontaneous process of nucleating quantum black holes. The energy-density of quantum black holes, depending on the initial temperature, gives the cosmological term, which naturally accounts for the inflationary phase of Early Universe. The reheating phase is attributed to the Hawking radiation and annihilation of these quantum black holes. Then, the radiation energy-density dominates over the energy-density of quantum black holes, the Universe started the Standard cosmology phase. In this phase the energy-density of quantum black holes depends on the reheating temperature. It asymptotically approaches to the cosmological constant in matter domination phase, consistently with current observations.