Constraints on axion inflation from the weak gravity conjecture

By Tom Rudelius. 2015

227 citations recorded by the source corpus.

We derive constraints facing models of axion inflation based on decay constant alignment from a string-theoretic and quantum gravitational perspective. In particular, we investigate the prospects for alignment and `anti-alignment' of C4 axion decay constants in type IIB string theory, deriving a strict no-go result in the latter case. We discuss the relationship of axion decay constants to the weak gravity conjecture and demonstrate agreement between our string-theoretic constraints and those coming from the `generalized' weak gravity conjecture. Finally, we consider a particular model of decay constant alignment in which the potential of C4 axions in type IIB compactifications on a Calabi-Yau three-fold is dominated by contributions from D7-branes, pointing out that this model evades some of the challenges derived earlier in our paper but is highly constrained by other geometric considerations.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/79e80395f9ec7971fd20e165f2cbc185c48f39b6

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Citations in the corpus

Early dark energy does not restore cosmological concordance (2020, background): “13 that the distribution of axion decay constants is highly peaked at f ∼ Mpl, in stark contrast with theory expectations, both from statistical arguments (Halverson et al. (2019)), and the Weak Gravity Conjecture (Arkani-Hamed et al. (2007)); see, e.g., Rudelius (2015b).”
Transplanckian axions!? (2015, background): “Notice that the generalized Weak Gravity Conjecture of [57] (see also [21, 22]) would have resulted in the more stringent bound M .”
The Swampland: Introduction and Review (2019, methodology): “19 There have been many studies related to this idea [7, 8, 26, 86, 105,106,109,111,115–149], some of which we will discuss in more detail in section 4.”
Recent Progress in the Physics of Axions and Axion-Like Particles (2020, unknown): “12) while giving ∆aL > MP [130–135].”
Sharpening the weak gravity conjecture with dimensional reduction (2015, background): “For example, it places certain theories of large-field inflation in the Swampland [4–15].”
Evidence for a sublattice weak gravity conjecture (2016, background): “From a phenomenological perspective, the WGC is especially interesting due to its ability to constrain models of large-field axion inflation [6–25].”
Euclidean Wormholes, Baby Universes, and Their Impact on Particle Physics and Cosmology (2018, background): “Setups in which the instanton that satisfies the WGC is not the one of lowest charge have been proposed as a loophole to this strong constraint [75,77,80] and are being actively investigated [79].”
Planckian axions and the Weak Gravity Conjecture (2015, methodology): “At the same time, it is precisely in the case P > N that the WGC fails to constrain axion alignment mechanisms [13–15] that could give rise to super-Planckian diameters in theories obeying the WGC [1, 3].”