Tuning Locked Inflation: Supergravity versus Phenomenology

TL;DR

This paper examines the cosmological implications of locked inflation, highlighting how a secondary saddle inflation phase can produce a scale-dependent spectrum that risks primordial black hole formation, thus constraining model parameters.

Contribution

It provides a detailed analysis of the end of locked inflation, revealing the potential for a secondary inflation phase and its impact on primordial fluctuations.

Findings

Secondary saddle inflation can follow locked inflation.

Scale-dependent spectrum may lead to black hole formation.

Parameter constraints are necessary to avoid cosmological disasters.

Abstract

We analyze the cosmological consequences of locked inflation, a model recently proposed by Dvali and Kachru that can produce significant amounts of inflation without requiring slow-roll. We pay particular attention to the end of inflation in this model, showing that a secondary phase of saddle inflation can follow the locked inflationary era. However, this subsequent period of inflation results in a strongly scale dependent spectrum that can lead to massive black hole formation in the primordial universe. Avoiding this disastrous outcome puts strong constraints on the parameter space open to models of locked inflation.