# Primordial Black Holes from String Inflation

## TL;DR

This paper proposes a string inflation model that naturally produces primordial black holes in the low mass range, potentially explaining dark matter, by leveraging a tunable potential with a plateau and inflection point.

## Contribution

It introduces a single-field string inflation model with a specific potential that enhances primordial black hole formation, grounded in string theory and stabilized by shift symmetry.

## Key findings

- Primordial black holes can form in the model's low mass region.
- The model's potential features a plateau and an inflection point.
- Parameter tunability is achieved via the string landscape.

## Abstract

We present a single-field string inflationary model which allows for the generation of primordial black holes in the low mass region where they can account for a significant fraction of the dark matter abundance. The potential is typical of type IIB fibre inflation models and features a plateau at CMB scales and a near inflection point at large distance scales where the power spectrum is enhanced due to a period of ultra slow-roll. The tunability of the underlying parameters is guaranteed by scanning through the string landscape and their stability against quantum corrections is ensured by an effective shift symmetry.