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We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year data set, and also from WMAP in combination with the Sloan Digital Sky Survey (SDSS)…

Astrophysics · Physics 2008-11-26 William H. Kinney , Edward W. Kolb , Alessandro Melchiorri , Antonio Riotto

Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its initial value below the Planck mass ($\phi_I \lesssim M_{Pl}$). In order for a…

High Energy Physics - Phenomenology · Physics 2017-03-08 Nobuchika Okada , Digesh Raut

We revisit the inflationary dynamics in detail for theories with Gauss-Bonnet gravity coupled to scalar functions, in light of the Planck data. Considering the chaotic inflationary scenario, we constrain the parameters of two models…

General Relativity and Quantum Cosmology · Physics 2017-02-08 Srijit Bhattacharjee , Debaprasad Maity , Rupak Mukherjee

We provide strong evidence for universality of the inflationary field range: given an accurate measurement of $(n_s,r)$, one can infer $\Delta \phi$ in a model-independent way in the sub-Planckian regime for a range of universality classes…

High Energy Physics - Theory · Physics 2015-01-09 Juan Garcia-Bellido , Diederik Roest , Marco Scalisi , Ivonne Zavala

A large inflationary tensor-to-scalar ratio $r_\mathrm{0.002} = 0.20^{+0.07}_{-0.05}$ is reported by the BICEP2 team based on their B-mode polarization detection, which is outside of the $95\%$ confidence level of the Planck best fit model.…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-24 Yi-Chao Li , Feng-Quan Wu , You-Jun Lu , Xue-Lei Chen

We present two families of multi-field potentials that support inflation while satisfying the refined de Sitter and the distance swampland conjectures. Both families feature Planck-compatible phenomenology. The first is a helix-type…

High Energy Physics - Theory · Physics 2020-04-29 Vikas Aragam , Sonia Paban , Robert Rosati

We show that non-minimal inflation, based on the phi^4 potential, may be rendered unitarity conserving and compatible with the Planck results for 4.6x10^(-3)<~r21=c2R/c1R^2<~1, if we introduce a linear contribution (c1R phi) to the frame…

High Energy Physics - Phenomenology · Physics 2018-12-31 C. Pallis

In this paper we report on a major theoretical observation in cosmology. We present a concrete cosmological model for which inflation has natural beginning and natural ending. Inflation is driven by a cosine-form potential, $V(\phi)=…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-05 Ishwaree P. Neupane

We study inflation within the framework of non-canonical scalar field. In this scenario, we obtain the inflationary observables such as the scalar spectral index, the tensor-to-scalar ratio, the running of the scalar spectral index as well…

General Relativity and Quantum Cosmology · Physics 2017-05-31 Zeinab Teimoori , Kayoomars Karami

The latest ACT data release disfavors the attractor $n_s=1-2/N$. In inflationary models with nonminimal coupling, such attractors typically arise in the strong coupling limit. To align with observational constraints, we focus on nonminimal…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-03 Qing Gao , Yungui Gong , Zhu Yi , Fengge Zhang

We implement Slow Roll Reconstruction -- an optimal solution to the inverse problem for inflationary cosmology -- within ModeCode, a publicly available solver for the inflationary dynamics. We obtain up-to-date constraints on the…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-10 Jorge Noreña , Christian Wagner , Licia Verde , Hiranya V. Peiris , Richard Easther

We investigate the observational viability of a class of $\alpha$-attractors inflationary models in light of the most recent Cosmic Microwave Background (CMB) and Large-Scale Structure (LSS) data. By considering a double-well potential we…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-04 J. G. Rodrigues , S. Santos da Costa , J. S. Alcaniz

We reconsider non-minimal \lambda \phi^4 chaotic inflation which includes the gravitational coupling term \xi \mathcal{R} \phi^2, where \phi denotes a gauge singlet inflaton field and \mathcal{R} is the Ricci scalar. For \xi >> 1 we…

High Energy Physics - Phenomenology · Physics 2014-11-21 Nobuchika Okada , Mansoor Ur Rehman , Qaisar Shafi

We revisit the status of hybrid inflation in the light of Planck and recent BICEP2 results, taking care of possible transient violations of the slow-roll conditions as the field passes from the large field to the vacuum dominated phase. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-05 Sebastien Clesse , Jeremy Rekier

Inflation is well known to be difficult in the context of supergravity, if the potential is dominated by the $F$ term. Non-renormalizable terms generically give $|V''|\sim V/M^2$, where $V(\phi)$ is the inflaton potential and $M$ is the…

High Energy Physics - Phenomenology · Physics 2009-10-30 David Lyth

Conventional wisdom says that a chaotic inflation model with a power-law potential is ruled out by the recent Planck-BICEP/Keck results. We find, however, that the model can be assisted by a non-minimally coupled scalar field and still…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 Sang Chul Hyun , Jinsu Kim , Seong Chan Park , Tomo Takahashi

In this work we revisit $\alpha$-Starobinsky inflation, also know as $E$-model, in the light of current CMB and LSS observations. The inflaton potential in the Einstein frame for this model contains a parameter $\alpha$ in the exponential,…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-11 Saisandri Saini , Akhilesh Nautiyal

Inflation is the leading theory to describe elegantly the initial conditions that led to structure formation in our universe. In this paper, we present a novel phenomenological fit to the Planck, WMAP polarisation (WP) and the BICEP2…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-24 Laura Barranco , Lotfi Boubekeur , Olga Mena

Single-field models of inflation are analysed in light of the WMAP five-year data. Assuming instantaneous reheating, we find that modular/new inflation models with small powers in the effective inflaton self-interaction are more strongly…

Astrophysics · Physics 2014-11-18 Laila Alabidi , James E. Lidsey

Future research studies of cosmic microwave background polarization seems likely to provide a more improved upper bound of $r \le 0.03$ on the tensor-to-scalar ratio(r). In our work, we have done the reheating study of mutated hilltop…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-12 Sudhava Yadav , Dhwani Gangal , K. K. Venkataratnam