Related papers: Natural Inflation From Fermion Loops

Chromo-Natural Inflation is the first worked example of a model of inflation in which slow-roll inflation is achieved by "magnetic drift" as opposed to Hubble friction. In this work, we give an account of the perturbations at linear order…

The natural inflation model with a periodic cosine potential is ruled out by recent Planck 2018 data for the decay constant $f \lesssim 5.5~M_{\rm Pl}$. If the Planck data is combined with the BICEP Keck array and BAO data, the model is…

A novel framework is proposed for embedding the natural inflation into the type IIA superstrings compactified on a Calabi-Yau (CY) three-fold. Inflaton is identified with axion of the Universal Hypermultiplet (UH). The other UH scalars…

In the so-called natural inflation, an axion-like inflaton is assumed to have a cosine-type periodic potential. This is not the case in a very simple model in which the axion-like inflaton is coupled to an SU(N) (or other) pure Yang-Mills,…

We propose a natural double inflation model in supergravity. In this model, chaotic inflation first takes place by virtue of the Nambu-Goldstone-like shift symmetry, which guarantees the absence of the exponential factor in the potential…

We show that inflation with a quadratic potential occurs naturally in theories where an axion-like field mixes with a 4-form. Such an axion is massive, with the mass which arises from the mixing being protected by the axion shift symmetry.…

We analyze a model of hybrid natural inflation based on the smallest non-Abelian discrete group S_3. Leading invariant terms in the scalar potential have an accidental global symmetry that is spontaneously broken, providing a…

In the ``natural inflation'' model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections…

Identifying the inflaton with a pseudo-Goldstone boson explains the flatness of its potential. Successful Goldstone Inflation should also be robust against UV corrections, such as from quantum gravity: in the language of the effective field…

We investigate how inflation can emerge from four-fermion interactions generated by spacetime torsion, eliminating the need for additional scalar fields beyond the Standard Model. We partition fermions in two sectors and introduce two bound…

A safe way to reheat the universe, in models of natural and quadratic inflation, is through shift symmetric couplings between the inflaton $\phi$ and the Standard Model (SM), since they do not generate loop corrections to the potential…

We propose a modification of the Natural Inflation (NI) potential in such a way that the spontaneous symmetry breaking scale $f$ can take values less than one (in Planck units). The proposed potential seems simple enough, however, its…

We study the Hybrid Natural Inflation (HNI) model and some of its realisations in the light of recent CMB observations, mainly Planck temperature and WMAP-9 polarization, and compare with the recent release of BICEP2 dataset. The…

A novel inflection-point inflation model is analysed. The model considers a massless scalar field, whose self-coupling's running is stabilised by a non-renormalisable operator. The running is controlled by a fermion loop. We find that…

We consider the gravitational generation of the massive Z-boson field of the standard model, due to the natural breaking of its conformal invariance during inflation. The electroweak symmetry restoration at the end of inflation turns the…

The model of Natural Inflation is examined in light of recent 3-year data from the Wilkinson Microwave Anisotropy Probe and shown to provide a good fit. The inflaton potential is naturally flat due to shift symmetries, and in the simplest…

Recent observations of the cosmic microwave background (CMB) indicate that a successful theory of cosmological inflation needs to have flat potential of the inflaton scalar field. Realizing the inflaton to be a pseudo-Nambu Goldstone boson…

We study constraints on the natural inflation model from the cosmic microwave background radiation (CMBR). Inflaton \phi for the natural inflation has a potential of the form V=\Lambda^4[1-\cos(\phi/\sqrt{2}f_\phi)], which is parametrized…

We propose an inflationary scenario based on a many-flavor hidden QCD with eight flavors, which realizes the almost scale-invariant (walking) gauge dynamics. The theory predicts two types of composite (pseudo) Nambu-Goldstone bosons, the…

In light of the five-year data from the Wilkinson Microwave Anisotropy Probe (WMAP), we discuss models of inflation based on the pseudo Nambu-Goldstone potential predicted in five-dimensional gauge theories for different backgrounds: flat…