Related papers: Kinetic Gravity Braiding and axion inflation
Based on our previous work, we constructed a phenomenological model of inflation with the higher derivative axion field in the light of recent cosmological expertiments BICEP2 and PLANCK. In order to achieve observed values for the…
In this paper we explored in detail a phenomenological model of modified single field natural inflation in light of recent cosmological experiments, BICEP2. Our main goal is to construct an inflationary model which not only predicts the…
The weak gravity conjecture imposes severe constraints on natural inflation. A trans-Planckian axion decay constant can only be realized if the potential exhibits an additional (subdominant) modulation with sub-Planckian periodicity. The…
We discuss inflation models within supersymmetry and supergravity frameworks with a landscape of chiral superfields and one $U(1)$ shift symmetry which is broken by non-perturbative symmetry breaking terms in the superpotential. We label…
We propose a landscape of many axions, where the axion potential receives various contributions from shift symmetry breaking effects. We show that the existence of the axion with a super-Planckian decay constant is very common in the axion…
Models of large-field inflation based on axion-like fields with shift symmetries can be simple and natural, and make a promising prediction of detectable primordial gravitational waves. The Weak Gravity Conjecture is known to constrain the…
We propose a natural inflation model driven by an imaginary or axionic component of a K\"ahler modulus in string-inspired supergravity. The shift symmetry of the axion is gauged under an anomalous $U(1)_X$ symmetry, which leads to a…
We present new constraints on spectator axion-${\rm U}(1)$ gauge field interactions during inflation using the latest $Planck$ (PR4) and BICEP/Keck 2018 data releases. This model can source tensor perturbations from amplified gauge field…
Models of axion inflation based on a single cosine potential require the axion decay constant $f$ to be super-Planckian in size. However, $f > M_{Pl}$ is disfavored by the Weak Gravity Conjecture (WGC). It is then pertinent to ask if one…
Because the inflationary mechanism is extremely sensitive to UV-physics, the construction of theoretically robust models of inflation provides a unique window on Planck-scale physics. We review efforts to use an axion with a shift symmetry…
If the inflaton is a pseudo-scalar axion, the axion shift symmetry can protect the flatness of its potential from too large radiative corrections. This possibility, known as natural inflation, requires an axion scale which is greater than…
Natural inflation relies on the existence of an axion decay constant which is super-Planckian. In string theory only sub-Planckian axion decay constants have been found in any controlled regime. However in field theory it is possible to…
Multiple axions form a landscape in the presence of various shift symmetry breaking terms. Eternal inflation populates the axion landscape, continuously creating new universes by bubble nucleation. Slow-roll inflation takes place after the…
The Weak Gravity Conjecture, if valid, rules out simple models of Natural Inflation by restricting their axion decay constant to be sub-Planckian. We revisit stringy attempts to realise Natural Inflation, with a single open string axionic…
We derive the requirements that a generic axion-like field has to satisfy in order to play the role of the inflaton field in the warm inflation scenario. Compared to the parameter space in ordinary natural inflation models, we find that the…
Pseudo-Goldstone bosons (pGBs) can provide technically natural inflatons, as has been comparatively well-explored in the simplest axion examples. Although inflationary success requires trans-Planckian decay constants, f > Mp, several…
We 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 space and/or from St\"uckelberg coupling to a U(1)…
In axion gauge field inflation an axion-like particle driving cosmic inflation is coupled to the Chern-Simons density of an Abelian or non-Abelian gauge group. In the case of a non-Abelian gauge group, this can lead to the formation of a…
With the Planck 2015 result, most of the well known canonical large field inflation models turned out to be strongly disfavored. Axion inflation is one of such models which is becoming marginalized with the increasing precession of CMB…
We study an extension of the natural inflation model comprising a non-Abelian gauge sector coupled to the axion-inflaton kinetic term. We show how such non-minimal coupling serves as a source of friction for the rolling inflaton granting…