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We investigate the dependency of Higgs inflation on the non-renormalisable matching between the low energy Standard Model limit and the inflationary regime at high energies. We show that for the top mass range $m_t \gtrsim 171.8$ GeV the…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Vera-Maria Enckell , Kari Enqvist , Sami Nurmi

The first year results of WMAP tentatively indicate running of the spectral index as well as a deficit of power in the low multipoles in the CMB spectrum. The former can be rather easily understood in the noncommutative inflation model, and…

Astrophysics · Physics 2009-11-10 Qing-Guo Huang , Miao Li

We derive constraints on a simple quintessential inflation model, based on a spontaneously broken Phi^4 theory, imposed by the Wilkinson Microwave Anisotropy Probe three-year data (WMAP3) and by galaxy clustering results from the Sloan…

Astrophysics · Physics 2008-11-26 Rogerio Rosenfeld , Joshua A. Frieman

We investigate a standard minimally-coupled scalar-field inflationary scenario, which is based on a new potential, with suitably generalized plateau features, that leads to extra small tensor-to-scalar ratios. In particular, we consider a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-13 Gerasimos Kouniatalis , Emmanuel N. Saridakis

We study to what extent the spectral index $n_s$ and the tensor-to-scalar ratio $r$ determine the field excursion $\Delta\phi$ during inflation. We analyse the possible degeneracy of $\Delta \phi$ by comparing three broad classes of…

High Energy Physics - Theory · Physics 2014-09-08 Juan Garcia-Bellido , Diederik Roest , Marco Scalisi , Ivonne Zavala

We perform a MCMC (Monte Carlo Markov Chains) analysis of the available CMB and LSS data (including the three years WMAP data) with single field slow-roll new inflation and chaotic inflation models. We do this within our approach to…

Astrophysics · Physics 2008-11-26 C. Destri , H. J. de Vega , N. G. Sanchez

During inflation, there is a preferred reference frame in which the expansion of the background spacetime is spatially isotropic. In contrast to Minkowski spacetime, observables can depend on the velocity of the system with respect to this…

General Relativity and Quantum Cosmology · Physics 2021-02-16 Tanguy Grall , Scott Melville

There is solid theoretical and observational motivation behind the idea of scale-invariance as a fundamental symmetry of Nature. We consider a recently proposed classically scale-invariant inflationary model, quadratic in curvature and…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-25 Chiara Cecchini , Mariaveronica De Angelis , William Giarè , Massimiliano Rinaldi , Sunny Vagnozzi

A spectral index n_s < 0.95 appears to be a generic prediction of racetrack inflation models. Reducing a general racetrack model to a single-field inflation model with a simple potential, we obtain an analytic expression for the spectral…

High Energy Physics - Theory · Physics 2008-11-26 Ph. Brax , Stephen C. Davis , M. Postma

In this paper, we investigate the noncommutative KKLMMT D3/anti-D3 brane inflation scenario in detail. Incorporation of the brane inflation scenario and the noncommutative inflation scenario can nicely explain the large negative running of…

High Energy Physics - Theory · Physics 2009-11-11 Xin Zhang

We show that the scale of the inflationary potential may be the electroweak scale or even lower, while still generating an acceptable spectrum of primordial density perturbations. Thermal effects readily lead to the initial conditions…

High Energy Physics - Phenomenology · Physics 2011-02-16 Gabriel German , Graham Ross , Subir Sarkar

Fundamental formulae representing the density perturbation spectrums generated in inflationary scenarios are rigorously proved. Quantum fluctuations as initial conditions for structure generation in some inflationary era can be calculated…

Astrophysics · Physics 2008-11-26 J. Hwang

The observational constraints on the primordial power spectrum have tightened considerably with the release of the first year analysis of the WMAP observations, especially when combined with the results from other CMB experiments and galaxy…

High Energy Physics - Phenomenology · Physics 2009-11-10 Dominik J. Schwarz , Cesar A. Terrero-Escalante

We extend the ModeCode software of Mortonson, Peiris and Easther to enable numerical computation of perturbations in K-inflation models, where the scalar field no longer has a canonical kinetic term. Focussing on models where the kinetic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Sheng Li , Andrew R. Liddle

We analyze the weak (2 sigma) evidence for a running spectral index seen in the three-year WMAP dataset and its implications for single field, slow roll inflation. We assume that the running is comparable to the central value found from the…

Astrophysics · Physics 2011-05-12 Richard Easther , Hiranya Peiris

One of the firm predictions of inflationary cosmology is the consistency relation between scalar and tensor spectra. It has been argued that such a relation -if experimentally confirmed- would offer strong support for the idea of inflation.…

General Relativity and Quantum Cosmology · Physics 2016-08-31 A. Ashoorioon , J. L. Hovdebo , R. B. Mann

We consider an intermediate Dirac-Born-Infeld (DBI) inflationary model in the presence of a minimal measurable length in the theory. We show that, the presence of a minimal measurable length modifies the definitions of the scalar and tensor…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-02 Narges Rashidi , Maryam Roushan , Kourosh Nozari

We examine the power-law Starobinsky model, a generalized version of the Starobinsky inflation model, characterized by a power-law correction to Einstein gravity. Employing the $f(R)$ formalism, the scalar and tensor power spectra were…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-10 Saisandri Saini , Akhilesh Nautiyal

We extend previous classifications of inflationary models by means of their behaviour at large-N, where N is the number of e-foldings. In addition to the perturbative 1/N case, whose slow-roll parameters fall off as powers of 1/N, we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Juan Garcia-Bellido , Diederik Roest

Constraints to the parameters of inflation models are often derived assuming some plausible range for the number--e.g., $N_k=46$ to $N_k=60$--of $e$-folds of inflation that occurred between the time that our current observable Universe…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-08 Julian B. Munoz , Marc Kamionkowski