Dark energy, QCD axion, BICEP2, and trans-Planckian decay constant

TL;DR

This paper explores the role of discrete symmetries in string theory, their connection to pseudo-Goldstone bosons like the QCD axion, and discusses implications of recent BICEP2 observations for cosmology.

Contribution

It analyzes the emergence of pseudo-Goldstone bosons from string compactifications and examines their relevance to dark energy, axion physics, and inflation in light of BICEP2 data.

Findings

Discrete symmetries lead to pseudo-Goldstone bosons such as the QCD axion.

Implications of BICEP2 data for inflationary models are discussed.

Connections between string theory symmetries and cosmological phenomena are highlighted.

Abstract

Discrete symmetries allowed in string compactification are the mother of all global symmetries which are broken at some level. We discuss the resulting pseudo-Goldstone bosons, in particular the QCD axion and a temporary cosmological constant, and inflatons. We also comment on some implications of the recent BICEP2 data.