Planckian axions in string theory

  title={Planckian axions in string theory},
  author={Thomas C. Bachlechner and Cody Long and Liam McAllister},
  journal={Journal of High Energy Physics},
A bstractWe argue that super-Planckian diameters of axion fundamental domains can arise in Calabi-Yau compactifications of string theory. In a theory with N axions θi, the fundamental domain is a polytope defined by the periodicities of the axions, via constraints of the form − π < Qijθj < π. We compute the diameter of the fundamental domain in terms of the eigenvalues f12 ≤ … ≤ fN2 of the metric on field space, and also, crucially, the largest eigenvalue of (QQ⊤)−1. At large N, QQ⊤ approaches… 

Planckian axions and the Weak Gravity Conjecture

A bstractSeveral recent works [1-3] have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence

Systematics of axion inflation in Calabi-Yau hypersurfaces

We initiate a comprehensive survey of axion inflation in compactifications of type IIB string theory on Calabi-Yau hypersurfaces in toric varieties. For every threefold with h1,1 ≤ 4 in the

Superradiance in string theory

We perform an extensive analysis of the statistics of axion masses and interactions in compactifications of type IIB string theory, and we show that black hole superradiance excludes some regions of

Large field inflation from axion mixing

A bstractWe study the general multi-axion systems, focusing on the possibility of large field inflation driven by axions. We find that through axion mixing from a non-diagonal metric on the moduli

Fencing in the swampland: quantum gravity constraints on large field inflation

A bstractIn this note we show that models of natural inflation based on closed string axions are incompatible with the weak gravity conjecture (WGC). Specifically, we use T- duality in order to map

Mirror quintic vacua: hierarchies and inflation

A bstractWe study the moduli space of type IIB string theory flux compactifications on the mirror of the CY quintic 3-fold in ℙ4$$ {\mathrm{\mathbb{P}}}^4 $$. We focus on the dynamics of the four

Phases of inflation

A bstractMotivated by the 4d effective field theories for closed string axions in Type II string compactifications with D-branes, we consider chiral gauge theories coupled to multiple axions. We

Systematics of aligned axions

A novel technique is described that renders theories of N axions tractable, and can be used to efficiently analyze a large class of periodic potentials of arbitrary dimension, and is found that in a broad class of random theories, the potential is smooth over diameters enhanced by N3/2 compared to the typical scale of the potential.

Hierarchies in Quantum Gravity: Large Numbers, Small Numbers, and Axions

We examine the relaxion mechanism in string theory. An essential feature is that an axion winds over N 1 fundamental periods. In string theory realizations via axion monodromy, this winding number

Large-field inflation with multiple axions and the weak gravity conjecture

A bstractIn this note, we discuss the implications of the weak gravity conjecture (WGC) for general models of large-field inflation with a large number of axions N. We first show that, from the



Planckian axions and the Weak Gravity Conjecture

A bstractSeveral recent works [1-3] have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence

The wasteland of random supergravities

A bstractWe show that in a general $ \mathcal{N} = {1} $ supergravity with N ≫ 1 scalar fields, an exponentially small fraction of the de Sitter critical points are metastable vacua. Taking the

Supersymmetric vacua in random supergravity

A bstractWe determine the spectrum of scalar masses in a supersymmetric vacuum of a general $ \mathcal{N}=1 $ supergravity theory, with the Kähler potential and superpotential taken to be random

The String landscape, black holes and gravity as the weakest force

We conjecture a general upper bound on the strength of gravity relative to gauge forces in quantum gravity. This implies, in particular, that in a four-dimensional theory with gravity and a U(1)

On the possibility of large axion moduli spaces

We study the diameters of axion moduli spaces, focusing primarily on type IIB compactifications on Calabi-Yau three-folds. In this case, we derive a stringent bound on the diameter in the large

On the Geometry of the String Landscape and the Swampland

Heavy tails in Calabi-Yau moduli spaces

A bstractWe study the statistics of the metric on Kähler moduli space in compactifications of string theory on Calabi-Yau hypersurfaces in toric varieties. We find striking hierarchies in the

Axion inflation and gravity waves in string theory

The majority of models of inflation in string theory predict an absence of measurable gravitational waves, $rll{10}^{\ensuremath{-}3}$. The most promising proposals for making string theoretic models

Axion inflation in type II string theory

Inflationary models driven by a large number of axion fields are discussed in the context of type IIB compactifications with N = 1 supersymmetry. The inflatons arise as the scalar modes of the R-R

Monodromy in the CMB: Gravity Waves and String Inflation

We present a simple mechanism for obtaining large-field inflation, and hence a gravitational wave signature, from string theory compactified on twisted tori. For nil manifolds, we obtain a leading