Supermassive primordial black holes in multiverse: for nano-Hertz gravitational wave and high-redshift JWST galaxies

TL;DR

This paper proposes a cosmological mechanism within the multiverse framework that naturally produces supermassive primordial black holes, potentially explaining the origins of supermassive black holes observed in the universe.

Contribution

It introduces a new formation scenario for supermassive primordial black holes via nucleation of supercritical bubbles during inflation, with a predicted mass distribution peaking above 10^11 solar masses.

Findings

Mass distribution of multiverse PBHs peaks at >10^11 solar masses.

Mechanism links inflationary bubble nucleation to supermassive black hole formation.

Provides a primordial origin for observed supermassive black holes.

Abstract

Recently, observational hints for supermassive black holes have been accumulating, which has inspired ones to wonder: Can primordial black holes (PBHs) be supermassive, in particular with the mass $M\gtrsim 10^{9}M_\odot$? A supercritical bubble (with an inflating baby universe inside it) that nucleated during inflation can develop into a PBH in our observable Universe. Here, we find that when the inflaton slowly passes by a neighboring vacuum, the nucleating rate of supercritical bubbles would inevitably attain a peak, so the mass distribution of multiverse PBHs, and the mass of peak can be up to $M\gtrsim 10^{11}M_\odot$. Thus our mechanism naturally provides a primordial origin of supermassive BHs.