# Primordial black hole tower: Dark matter, earth-mass, and LIGO black holes

## TL;DR

This paper proposes a multi-phase inflation model that produces a hierarchical spectrum of primordial black holes, potentially explaining dark matter, LIGO black holes, and microlensing events within a unified framework.

## Contribution

It introduces a novel multi-phase inflation scenario that naturally generates a broad mass spectrum of primordial black holes, linking them to dark matter and astrophysical observations.

## Key findings

- Simultaneous formation of PBHs across multiple mass scales.
- Potential explanation for dark matter, LIGO black holes, and microlensing events.
- Supports multi-phase inflation with hierarchical PBH spectrum as a transition signal.

## Abstract

We investigate a possibility of primordial black hole (PBH) formation with a hierarchical mass spectrum in multiple phases of inflation. As an example, we find that one can simultaneously realize a mass spectrum which has recently attracted a lot of attention: stellar-mass PBHs ($\sim\mathcal{O}(10)M_\odot$) as a possible source of binary black holes detected by LIGO/Virgo collaboration, asteroid-mass ($\sim\mathcal{O}(10^{-12})M_\odot$) as a main component of dark matter, and earth-mass ($\sim\mathcal{O}(10^{-5})M_\odot$) as a source of ultrashort-timescale events in Optical Gravitational Lensing Experiment microlensing data. The recent refined de Sitter swampland conjecture may support such a multi-phase inflationary scenario with hierarchical mass PBHs as a transition signal of each inflationary phase.