In this chapter, we will learn about axion inflation in field theory, how axions appear in string theory, and a specific set-up for string inflation that has been very popular recently, axion monodromy.

The present work suggests that the isocurvature tension between axion and high energy inflationary scenarios may be avoided by considering a double field inflationary model involving the hidden Peccei–Quinn Higgs and the ...

Because of their quantum fluctuations, axion fields had a chance to experience field excursions traversing many minima of their potentials during inflation. We study this situation by analyzing the dynamics of an axion ...

We study a scenario allowing a solution of the strong charge parity problem via the Peccei-Quinn mechanism, implemented in gravity with torsion. In this framework there appears a torsion-related pseudoscalar field known ...

The recent detection of the cosmic microwave background polarimeter experiment BICEP2 of tensor fluctuations in the B-mode power spectrum basically excludes all plausible axion models where its decay constant is above ...

We propose a simple toy model for quintessential inflation where a complex scalar field described by a Lagrangian with a U(1)(PQ) symmetry spontaneously broken at a high energy scale and explicitly broken by instanton ...

We propose a simple toy model for quintessential inflation where a complex scalar field described by a Lagrangian with a U(1)(PQ) symmetry spontaneously broken at a high energy scale and explicitly broken by instanton ...