Axion Physics from String Theory: Cosmological Signatures in Dark Matter and Inflation

TL;DR

This paper reviews how string theory predicts axion-like particles that could explain dark matter, dark energy, and inflation, highlighting their theoretical origins and potential observational signatures.

Contribution

It provides a comprehensive overview of axion physics from string theory, emphasizing their cosmological roles and implications for future experiments.

Findings

String theory predicts a spectrum of axion-like particles from compactification.

Axions can serve as candidates for dark matter and dark energy.

Implications for observational signatures in cosmology are discussed.

Abstract

The quest to understand the nature of dark matter and dark energy motivates a deep exploration into axion physics, particularly within the framework of string theory. Axions, originally proposed to solve the strong CP problem, emerge as compelling candidates for both dark matter and dark energy components of the universe. String theory, offering a unified perspective on fundamental forces, predicts a rich spectrum of axion-like particles (ALPs) arising from its compactification schemes. This paper provides a comprehensive review of axion physics within string theory, detailing their theoretical foundations, emergence from compactification processes, and roles in cosmological models. Key aspects covered include the Peccei-Quinn mechanism, the structure of ALPs, their moduli stabilization, and implications for observational signatures in dark matter, dark energy, and cosmological inflation scenarios. Insights from ongoing experimental efforts and future directions in axion cosmology are also discussed