Primordial Black Hole Reheating

TL;DR

This paper investigates a novel reheating mechanism in the early universe through primordial black hole evaporation, offering alternative scenarios to the standard inflaton decay process and analyzing different PBH mass distributions.

Contribution

It introduces a new reheating pathway via PBH evaporation, exploring conditions under which PBHs dominate or solely reheat the universe, with detailed parameter analysis.

Findings

Reheating can occur through PBH evaporation instead of inflaton decay.

Two distinct reheating scenarios depend on PBH initial conditions.

Parameter ranges for different PBH mass functions are identified.

Abstract

Post-inflationary reheating phase is usually said to be solely governed by the decay of coherently oscillating inflaton into radiation. In this submission, we explore a new avenue toward reheating through the evaporation of primordial black holes (PBHs). After the inflation, if PBHs form, depending on its initial mass, abundance, and inflaton coupling with the radiation, we found two physically distinct possibilities of reheating the universe. In one possibility, the thermal bath is solely obtained from the decay of PBHs while inflaton plays the role of dominant energy component in the entire process. In the other possibility, we found that PBHs itself dominate the total energy budget of the Universe during the course of evolution, and then its subsequent evaporation leads to radiation dominated universe. Furthermore, we analyze the impact of both monochromatic and extended PBH mass functions and estimate the detailed parameter ranges for which those distinct reheating histories are realized.