Flux couplings to string theory axions yield super-Planckian field ranges along which the axion potential energy grows. At the same time, other aspects of the physics remain essentially unchanged along these large displacements, respecting a discrete shift symmetry with a sub-Planckian period. After a general overview of this monodromy effect and its application to large-field inflation, we present new classes of specific models of monodromy inflation, with monomial potentials μ4−pϕp. A key simplification in these models is that the inflaton potential energy plays a leading role in moduli stabilization during inflation. The resulting inflaton-dependent shifts in the moduli fields lead to an effective flattening of the inflaton potential, i.e. a reduction of the exponent from a fiducial value p0 to p < p0. We focus on examples arising in compactifications of type IIB string theory on products of tori or Riemann surfaces, where the inflaton descends from the NS-NS two-form potential B2, with monodromy induced by a coupling to the R-R field strength F1. In this setting we exhibit models with p = 2/3, 4/3, 2, and 3, corresponding to predictions for the tensor-to-scalar ratio of r ≈ 0.04, 0.09, 0.13, and 0.2, respectively. Using mirror symmetry, we also motivate a second class of examples with the role of the axions played by the real parts of complex structure moduli, with fluxes inducing monodromy.
Cosmology of Theories beyond the SM Flux compactifications
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
A.H. Guth, The inflationary universe: a possible solution to the horizon and flatness problems, Phys. Rev.D 23 (1981) 347 [INSPIRE].ADSGoogle Scholar
A.D. Linde, A new inflationary universe scenario: a possible solution of the horizon, flatness, homogeneity, isotropy and primordial monopole problems, Phys. Lett.B 108 (1982) 389 [INSPIRE].MathSciNetCrossRefADSGoogle Scholar
A. Albrecht and P.J. Steinhardt, Cosmology for grand unified theories with radiatively induced symmetry breaking, Phys. Rev. Lett.48 (1982) 1220 [INSPIRE].CrossRefADSGoogle Scholar
A.A. Starobinsky, Dynamics of phase transition in the new inflationary universe scenario and generation of perturbations, Phys. Lett.B 117 (1982) 175 [INSPIRE].CrossRefADSGoogle Scholar
A.A. Starobinsky, The perturbation spectrum evolving from a nonsingular initially de-Sitter cosmology and the microwave background anisotropy, Sov. Astron. Lett.9 (1983) 302 [INSPIRE].ADSGoogle Scholar
J.M. Bardeen, J.R. Bond, N. Kaiser and A.S. Szalay, The statistics of peaks of Gaussian random fields, Astrophys. J.304 (1986) 15 [INSPIRE].CrossRefADSGoogle Scholar
K.N. Abazajian et al., Inflation physics from the cosmic microwave background and large scale structure, arXiv:1309.5381 [INSPIRE].
K. Freese, J.A. Frieman and A.V. Olinto, Natural inflation with pseudo-Nambu-Goldstone bosons, Phys. Rev. Lett.65 (1990) 3233 [INSPIRE].CrossRefADSGoogle Scholar
F.C. Adams, J.R. Bond, K. Freese, J.A. Frieman and A.V. Olinto, Natural inflation: particle physics models, power law spectra for large scale structure and constraints from COBE, Phys. Rev.D 47 (1993) 426 [hep-ph/9207245] [INSPIRE].ADSGoogle Scholar
Planck collaboration, P.A.R. Ade et al., Planck 2013 results. XXII. Constraints on inflation, arXiv:1303.5082 [INSPIRE].
P.D. Meerburg, D.N. Spergel and B.D. Wandelt, Searching for oscillations in the primordial power spectrum. I. Perturbative approach, Phys. Rev.D 89 (2014) 063536 [arXiv:1308.3704] [INSPIRE].ADSGoogle Scholar
P.D. Meerburg and D.N. Spergel, Searching for oscillations in the primordial power spectrum. II. Constraints from Planck data, Phys. Rev.D 89 (2014) 063537 [arXiv:1308.3705] [INSPIRE].ADSGoogle Scholar
M. Aich, D.K. Hazra, L. Sriramkumar and T. Souradeep, Oscillations in the inflaton potential: complete numerical treatment and comparison with the recent and forthcoming CMB datasets, Phys. Rev.D 87 (2013) 083526 [arXiv:1106.2798] [INSPIRE].ADSGoogle Scholar