Ultracompact minihalos as probes of inflationary cosmology

TL;DR

This paper explores how ultracompact minihalos formed from primordial density perturbations can serve as probes for inflationary cosmology, offering new observational constraints on inflation models.

Contribution

It introduces the concept of using ultracompact minihalos as novel observational tools to extend inflationary constraints beyond CMB scales.

Findings

Minihalos can form from small-scale perturbations before standard structure formation.

Minihalos influence pulsar timing and gamma-ray observations.

Constraints from minihalos extend the observable inflationary window.

Abstract

Cosmological inflation generates primordial density perturbations on all scales, including those far too small to contribute to the cosmic microwave background. At these scales, isolated ultracompact minihalos of dark matter can form well before standard structure formation, if the perturbations have sufficient amplitude. Minihalos affect pulsar timing data and are potentially bright sources of gamma rays. The resulting constraints significantly extend the observable window of inflation in the presence of cold dark matter, coupling two of the key problems in modern cosmology.