Conceptual Problems of Inflationary Cosmology and a New Approach to Cosmological Structure Formation

TL;DR

This paper critiques the conceptual issues in inflationary cosmology and explores how string theory might offer alternative mechanisms for the universe's early structure formation.

Contribution

It proposes a new approach to cosmological structure formation based on string theory, challenging traditional inflationary models.

Findings

String theory may produce a different cosmological background than inflation.

A new stringy mechanism could generate scale-invariant fluctuations.

Current inflation models face unresolved conceptual problems.

Abstract

In spite of its great phenomenological success, current models of scalar field-driven inflation suffer from important unresolved conceptual issues. New fundamental physics will be required to address these questions. String theory is a candidate for a unified quantum theory of all four forces of nature. As will be shown, string theory may lead to a cosmological background quite different from an inflationary cosmology, and may admit a new stringy mechanism for the origin of a roughly scale-invariant spectrum of cosmological fluctuations.