D7‐brane moduli space in axion monodromy and fluxbrane inflation

233

339

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 µ 4−p φ p . 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 p 0 to p < p 0 . 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 B 2 , with monodromy induced by a coupling to the R-R field strength F 1 . 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.

Section: Dual Axionsmentioning

confidence: 99%

Section: Jhep09(2014)123mentioning

confidence: 99%

The powers of monodromy

McAllister

Silverstein

Westphal

et al. 2014

233

339

“…In [34] a scenario based on the universal axion C 0 was discussed, where it was argued that this axion provides a natural mechanism for reheating to occur mainly into Standard Model degrees of freedom. In [8,35] the inflaton was given by a deformation modulus of a D7-brane which was argued to enjoy a shift symmetry (at special points in the moduli space). In [9] the axion was identified with an open-string modulus, namely the superpartner in the Higgs sector of the MSSM.…”

Section: Jhep01(2015)007mentioning

confidence: 99%

The challenge of realizing F-term axion monodromy inflation in string theory

Blumenhagen

Herschmann

Plauschinn

2015

128

A systematic analysis of possibilities for realizing single-field F-term axion monodromy inflation via the flux-induced superpotential in type IIB string theory is performed. In this well-defined setting the conditions arising from moduli stabilization are taken into account, where we focus on the complex-structure moduli but ignore the Kähler moduli sector. Our analysis leads to a no-go theorem, if the inflaton involves the universal axion. We furthermore construct an explicit example of F-term axion monodromy inflation, in which a single axion-like field is hierarchically lighter than all remaining complexstructure moduli.

“…Here κ ijkl denote the classical intersection numbers of the divisors of the mirror dual four-fold, as discussed in [34][35][36][37]. We will consider flux compactifications of F-theory in which the four-form flux G 4 on the corresponding cycle does not vanish.…”

Section: Jhep03(2016)064mentioning

confidence: 99%

Universal properties of type IIB and F-theory flux compactifications at large complex structure

Marsh¹,

Sousa²

2016

Abstract:We consider flux compactifications of type IIB string theory and F-theory in which the respective superpotentials at large complex structure are dominated by cubic or quartic terms in the complex structure moduli. In this limit, the low-energy effective theory exhibits universal properties that are insensitive to the details of the compactification manifold or the flux configuration. Focussing on the complex structure and axio-dilaton sector, we show that there are no vacua in this region and the spectrum of the Hessian matrix is highly peaked and consists only of three distinct eigenvalues (0, 2m 2 3/2 and 8m 2 3/2 ), independently of the number of moduli. We briefly comment on how the inclusion of Kähler moduli affect these findings. Our results generalise those of Brodie & Marsh [1], in which these universal properties were found in a subspace of the large complex structure limit of type IIB compactifications.