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We carry out numerical investigations of the perturbations in Nflation models where the mass spectrum is generated by random matrix theory. The tensor-to-scalar ratio and non-gaussianity are already known to take the single-field values,…

Astrophysics · Physics 2008-12-18 Soo A Kim , Andrew R Liddle

Taking field theory seriously, inflation model-building is difficult but not impossible. The observed value of the spectral index of the adiabatic density perturbation is starting to discriminate between models, and may well pick out a…

High Energy Physics - Phenomenology · Physics 2009-10-31 David H Lyth

The prediction of a nearly scale-invariant spectrum of curvature and tensor fluctuations is among the main features of cosmic inflation. The current measurements of the primordial fluctuations in the cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-30 Marcos A. G. Garcia , Aline Pereyra-Flores

Bayesian model comparison penalizes models with more free parameters that are allowed to vary over a wide range, and thus offers the most robust method to decide whether some given data require new parameters. In this paper, we ask a simple…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-28 Tommaso Giannantonio , Eiichiro Komatsu

Most models of inflation have small parameters, either to guarantee sufficient inflation or the correct magnitude of the density perturbations. In this paper we show that, in supersymmetric theories with weak scale supersymmetry breaking,…

High Energy Physics - Phenomenology · Physics 2009-09-15 Lisa Randall , Marin Soljacic , Alan Guth

The scale at which supersymmetry is broken and the mechanism by which supersymmetry breaking is fed down to the observable sector has rich implications on the way Nature may have chosen to accomplish inflation. We discuss a simple model for…

High Energy Physics - Phenomenology · Physics 2014-11-17 Antonio Riotto

We conduct a model-independent analysis of temporal features during inflation in the large-scale CMB temperature power spectrum allowing for the possibility of non-negligible tensor contributions. Of 20 principal components of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Wayne Hu , Cora Dvorkin

In inflation cosmologies, cosmic structure develops through the gravitational instability of the inevitable quantum noise in primordial scalar fields. I show how the acceleration of the universe defines the shape of the primordial spectrum…

Astrophysics · Physics 2009-09-25 J. Richard Bond

Observational constraints guide one forcefully to examine models in which the matter density is substantially less than critical density. Particularly noteworthy are those which are consistent with inflation. For these models, microwave…

Astrophysics · Physics 2007-05-23 J. P. Ostriker , Paul J. Steinhardt

We study thermally induced density perturbations during inflation. This scenario is characterized by two thermodynamical conditions: (1) The primordial perturbations originate in the epoch when the inflationary universe contains a…

Astrophysics · Physics 2009-10-30 Wolung Lee , Li-Zhi Fang

The spectrum of cosmological perturbations in the context of the one-bubble open inflation model is discussed, taking into account fluctuations of the metric. We find that, quite generically,thin wall single field models have no…

Astrophysics · Physics 2009-10-09 Jaume Garriga , Xavier Montes , Misao Sasaki , Takahiro Tanaka

Motivated by the prospect of testing inflation from precision cosmic microwave background observations, we present analytic results for scalar and tensor perturbations in single-field inflation models based on the application of uniform…

Astrophysics · Physics 2009-11-07 Salman Habib , Katrin Heitmann , Gerard Jungman , Carmen Molina-Paris

We study a model of inflation where the scalar perturbations are almost gaussian while there is sizable (equilateral) nongaussianity in the tensor sector. In this model, a rolling pseudoscalar gravitationally coupled to the inflaton…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-28 Jessica L. Cook , Lorenzo Sorbo

We construct a no-scale model of inflation with a single modulus whose real and imaginary parts are fixed by simple power-law corrections to the no-scale K{\" a}hler potential. Assuming an uplift of the minimum of the effective potential,…

High Energy Physics - Phenomenology · Physics 2018-11-21 John Ellis , Malcolm Fairbairn , Antonio Enea Romano , Oscar Zapata

We review the main theoretical aspects of the structure formation paradigm which impinge upon wide angle surveys: the early universe generation of gravitational metric fluctuations from quantum noise in scalar inflaton fields; the well…

Astrophysics · Physics 2007-05-23 J. R. Bond , L. Kofman , D. Pogosyan , J. Wadsley

We use cosmic microwave background and large scale structure data to test a broad and physically well-motivated class of inflationary models: those with flat tree-level potentials (typical in supersymmetry). The non-trivial features of the…

High Energy Physics - Phenomenology · Physics 2009-03-24 G. Ballesteros , J. A. Casas , J. R. Espinosa , R. Ruiz de Austri , R. Trotta

We propose a new mechanism to generate density perturbations in inflationary models. Spatial fluctuations in the decay rate of the inflaton field to ordinary matter lead to fluctuations in the reheating temperature. We argue that in most…

Astrophysics · Physics 2009-11-07 Gia Dvali , Andrei Gruzinov , Matias Zaldarriaga

We supply fitting formulae enabling the normalization of slow-roll inflation models to the four-year COBE data. We fully include the effect of the gravitational wave modes, including the predicted relation of the amplitude of these modes to…

Astrophysics · Physics 2008-11-26 Emory F Bunn , Andrew R Liddle , Martin White

Recent BICEP/Keck data on the cosmic microwave background, in combination with previous WMAP and Planck data, impose strong new constraints on the tilt in the scalar perturbation spectrum, $n_s$, as well as the tensor-to-scalar ratio, $r$.…

High Energy Physics - Phenomenology · Physics 2022-02-16 John Ellis , Marcos A. G. Garcia , Dimitri V. Nanopoulos , Keith A. Olive , Sarunas Verner

We present constraints on canonical single-field inflation derived from WMAP five year, ACBAR, QUAD, BICEP data combined with the halo power spectrum from SDSS LRG7. Models with a non-scale-invariant spectrum and a red tilt n_s < 1 are now…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 Fabio Finelli , Jan Hamann , Samuel M. Leach , Julien Lesgourgues