High scale inflation, model-independent string axion, and QCD axion with domain wall number one

Jihn E Kim

doi:10.1016/j.physletb.2014.05.033

Abstract

The recent BICEP2 result shows that the Universe once has gone through the vacuum with the GUT scale energy density. The implied high scale inflation nullifies the dilution idea of topological defects, strings and domain walls, of the axionic system. In particular, domain walls are disastrous if the domain wall problem with NDW≥2 is present. We argue that the model-independent axion in string compactification with the anomalous U(1)ga gauge symmetry resolves the domain wall problem naturally with a symmetry principle.

Highlights

The recent report [1] on a possible significant nonzero B-mode polarization has attracted a great deal of attention [2,3,4,5,6]
Even though this report has to be proved being consistent with the previous Planck data on the tensor to scalar ratio r [7], just the existence of a grand unification (GUT) scale vacuum energy density constrains many theoretical ideas suggested so far
The recent BICEP2 result implies that the inflationary phase has ended at HI ≃ 1014 GeV which is above the expected QCD axion window: fa, GeV = [1010, 1012]

Summary

INTRODUCTION

The recent report [1] on a possible significant nonzero B-mode polarization has attracted a great deal of attention [2,3,4,5,6]. Even though this report has to be proved being consistent with the previous Planck data on the tensor to scalar ratio r [7], just the existence of a GUT scale vacuum energy density constrains many theoretical ideas suggested so far This high scale inflation answers to a long-standing question in axion cosmology, “Has the Peccei-Quinn (PQ) symmetry breaking occurred before or after the inflationary epoch?”. These small bubbles will collide with the horizon scale string-wall system, but the effect is not erasing the horizon scale wall as shown in (c) and (d) of Fig. 2 Another issue related to the PQ phase transition after inflation is the feasibility of QCD axion detection [22].

THE EFFECT OF MODEL-INDEPENDENT AXION TO QCD AXION

TWO CONFINING FORCES AND MI AXION

CONCLUSION