Helical Inflation and Cosmic Strings

Abstract

Recent BICEP2 detection of low-multipole B-mode polarization anisotropy in the cosmic microwave background radiation supports the inflationary universe scenario and suggests a large inflaton field range. The latter feature can be achieved with axion fields in the framework of string theory. We present such a helical model which naturally becomes a model with a single cosine potential, and which in turn reduces to the (quadratic) chaotic inflation model in the super-Planckian limit. The slightly smaller tensor/scalar ratio $r$ of models of this type provides a signature of the periodic nature of an axion potential. We present a simple way to quantify this distinctive feature. As axions are intimately related to strings/vortices and strings are ubiquitous in string theory, we explore the possibility that cosmic strings may be contributing to the B-mode polarization anisotropy observed.

18 pages, 2 figures. Correct a typo in the 2 tables. Reword the introductory remarks on inflation and cosmic strings. Add a reference

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Cited by in corpus (13)

• The Powers of Monodromy
• Transplanckian axions !?
• Aligned Natural Inflation: Monodromies of two Axions
• D7-Brane Moduli Space in Axion Monodromy and Fluxbrane Inflation
• Hierarchical Axion Inflation
• Planckian Axions in String Theory
• Towards Natural Inflation in String Theory
• Axion monodromy inflation with multi-natural modulations
• Hypercharge Axion and the Diphoton $750$ GeV Resonance
• Towards natural inflation from weakly coupled heterotic string theory
• Generalized Clockwork Theory
• Phases of Inflation
• Lensing dispersion of SNIa and small scales of the primordial power spectrum