LENGTH OF INFLATION AND NON-GAUSSIANITY

2011 ◽  
Vol 20 (03) ◽  
pp. 361-370
Author(s):  
SHIRO HIRAI ◽  
TOMOYUKI TAKAMI
Keyword(s):  
Nonlinearity Parameter ◽  
Slow Roll ◽  
Higher Derivative ◽  
Scalar Matter ◽  
Special Cases ◽  
Slow Roll Inflation

Certain inflation models are shown to have large non-Gaussianity in special cases. Namely, slow-roll inflation models with an effective higher derivative interaction, in which the length of inflation is finite and a scalar-matter-dominated period or power inflation is adopted as pre-inflation, are considered. Using Holman and Tolley's formula of the nonlinearity parameter in the flattened triangle configurations [Formula: see text], we calculate the value of [Formula: see text]. The value of [Formula: see text] is found to be largest [Formula: see text] when the inflation length is approximately 60 e-folds, and [Formula: see text] is found to depend strongly on the length of inflation and the cut-off scale.

scholarly journals Slow-roll inflation with exponential potential in scalar-tensor models

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
L. N. Granda ◽  
D. F. Jimenez
Keyword(s):  
Scalar Field ◽  
Order Approximation ◽  
Energy Scale ◽  
Model Parameters ◽  
Exponential Potential ◽  
Minimal Coupling ◽  
Slow Roll ◽  
Special Cases ◽  
First Order Approximation ◽  
Slow Roll Inflation

Abstract A study of the slow-roll inflation for an exponential potential in the frame of the scalar-tensor theory is performed, where non-minimal kinetic coupling to curvature and non-minimal coupling of the scalar field to the Gauss-Bonnet invariant are considered. Different models were considered with couplings given by exponential functions of the scalar field, that lead to graceful exit from inflation and give values of the scalar spectral index and the tensor-to-scalar ratio in the region bounded by the current observational data. Special cases were found, where the coupling functions are inverse of the potential, that lead to inflation with constant slow-roll parameters, and it was possible to reconstruct the model parameters for given ns and r. In first-order approximation the standard consistency relation maintains its validity in the model with non-minimal coupling, but it modifies in presence of Gauss–Bonnet coupling. The obtained Hubble parameter during inflation, $$H\sim 10^{-5} M_p$$H∼10-5Mp and the energy scale of inflation $$V^{1/4}\sim 10^{-3} M_p$$V1/4∼10-3Mp, are consistent with the upper bounds set by latest observations.

scholarly journals Generalized slow-roll inflation

2000 ◽  
Vol 269 (4) ◽  
pp. 209-213 ◽  
Author(s):  
Valerio Faraoni
Keyword(s):  
Slow Roll ◽  
Slow Roll Inflation

scholarly journals THE N-TACHYON ASSISTED INFLATION

2007 ◽  
Vol 22 (36) ◽  
pp. 2737-2748 ◽  
Author(s):  
HARVENDRA SINGH
Keyword(s):  
Open String ◽  
Slow Roll ◽  
Slow Roll Inflation

In continuation of the papers hep-th/0505012 and hep-th/0508101 we investigate the consequences when N open-string tachyons roll down simultaneously. We demonstrate that the N-tachyon system coupled to gravity does indeed give rise to the assisted slow-roll inflation.

scholarly journals NATURAL SLOW-ROLL INFLATION

1996 ◽  
Vol 11 (08) ◽  
pp. 631-646 ◽  
Author(s):  
R.F. LANGBEIN ◽  
K. LANGFELD ◽  
H. REINHARDT ◽  
L. von SMEKAL
Keyword(s):  
Phase Change ◽  
Early Universe ◽  
Slow Roll ◽  
Slow Roll Inflation

It is shown that the nonperturbative dynamics of a phase change to the nontrivial phase of λφ4-theory in the early universe can give rise to slow-rollover inflation without recourse to unnaturally small couplings.

scholarly journals Inflation and supersymmetry breaking in Higgs-R2 supergravity

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Shuntaro Aoki ◽  
Hyun Min Lee ◽  
Adriana G. Menkara
Keyword(s):  
Supersymmetry Breaking ◽  
Planck Scale ◽  
Scalar Fields ◽  
Minimal Coupling ◽  
Slow Roll ◽  
New Construction ◽  
Visible Sector ◽  
Higgs Fields ◽  
Chiral Superfields ◽  
Slow Roll Inflation

Abstract We propose a new construction of the supergravity inflation as an UV completion of the Higgs-R2 inflation. In the dual description of R2-supergravity, we show that there appear dual chiral superfields containing the scalaron or sigma field in the Starobinsky inflation, which unitarizes the supersymmetric Higgs inflation with a large non-minimal coupling up to the Planck scale. We find that a successful slow-roll inflation is achievable in the Higgs-sigma field space, but under the condition that higher curvature terms are introduced to cure the tachyonic mass problems for spectator singlet scalar fields. We also discuss supersymmetry breaking and its transmission to the visible sector as a result of the couplings of the dual chiral superfields and the non-minimal gravity coupling of the Higgs fields.

scholarly journals SPECTRUM OF GRAVITATIONAL WAVES IN KREIN SPACE QUANTIZATION

2011 ◽  
Vol 26 (36) ◽  
pp. 2697-2702 ◽  
Author(s):  
M. MOHSENZADEH ◽  
A. SOJASI ◽  
E. YUSOFI
Keyword(s):  
Gravitational Waves ◽  
Krein Space ◽  
Slow Roll ◽  
Primordial Power Spectrum ◽  
Alternative Approach ◽  
Special Cases ◽  
Kreĭn Space ◽  
Field Quantization ◽  
Krein Space Quantization ◽  
Scalar Perturbations

The main goal of this paper is to derive the primordial power spectrum for the scalar perturbations generated as a result of quantum fluctuations during an inflationary period by an alternative approach of field quantization.1–3 Formulas are derived for the gravitational waves, special cases of which include power law inflation and inflation in the slow roll approximation, in Krein space quantization.

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