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Cosmological perturbations, originating in the quantum fluctuations of the fields that drive inflation, are observed to be nearly scale invariant at the largest scales. At smaller scales, however, perturbations are not severely constrained…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-09 Ioannis Dalianis

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…

High Energy Physics - Phenomenology · Physics 2008-11-26 Christopher Savage , Katherine Freese , William H. Kinney

The Wilkinson Microwave Anisotropy Probe (WMAP) mapped the distribution of temperature and polarization over the entire sky in five microwave frequency bands. These full-sky maps were used to obtain measurements of temperature and…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Eiichiro Komatsu , Charles L. Bennett

A possible origin of the anomalous dip and bump in the primordial power spectrum, which are reconstructed from WMAP data corresponding to the multipole $\ell=100\sim 140$ by using the inversion method, is investigated as a consequence of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kohei Kumazaki , Shuichiro Yokoyama , Naoshi Sugiyama

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…

High Energy Physics - Phenomenology · Physics 2008-11-26 Katherine Freese , William H. Kinney , Christopher Savage

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…

Astrophysics · Physics 2008-11-26 Xiulian Wang , Bo Feng , Mingzhe Li , Xue-Lei Chen , Xinmin Zhang

Measurements of CMB temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry…

Astrophysics · Physics 2008-12-30 Adrienne L. Erickcek , Marc Kamionkowski , Sean M. Carroll

If the initial state of the inflaton field is taken to have a thermal distribution instead of the conventional zero particle vacuum state then the curvature power spectrum gets modified by a temperature dependent factor such that the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Kaushik Bhattacharya , Subhendra Mohanty , Raghavan Rangarajan

The effect of the length of inflation on the power spectra of scalar and tensor perturbations is estimated using the power-law inflation model with a scale factor of a(t) = t^q. Considering various pre-inflation models with…

Astrophysics · Physics 2007-05-23 Shiro Hirai , Tomoyuki Takami

In inflationary models with minimal amount of gravity waves, the primordial power spectrum of density fluctuations, $A_S^2(k)$, together with the basic cosmological parameters, completely specify the predictions for the cosmic microwave…

Astrophysics · Physics 2009-10-31 Yun Wang , David N. Spergel , Michael A. Strauss

The Wilkinson Microwave Anisotropy Probe microwave background data suggest that the primordial spectrum of scalar curvature fluctuations is suppressed at small wavenumbers. We propose a UV/IR mixing effect in small-field inflationary models…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Buchel , F. A. Chishtie , V. Elias , Katherine Freese , R. B. Mann , D. G. C. McKeon , T. G. Steele

We investigate inflationary scenarios driven by a class of potentials which are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of…

The basic cosmological parameters and the primordial power spectrum together completely specify predictions for the cosmic microwave background radiation anisotropy and large scale structure. Here we show how we can strongly constrain both…

Astrophysics · Physics 2010-11-30 Yun Wang , David N. Spergel , Michael A. Strauss

We investigate the ability of current CMB data to reliably constrain the form of the primordial power spectrum generated during inflation. We attempt to identify more exotic power spectra that yield equally good fits to the data as simple…

Astrophysics · Physics 2009-06-23 Brian A. Powell , William H. Kinney

We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) data set, and from a combination of the WMAP data and seven other Cosmic Microwave Background (CMB)…

High Energy Physics - Phenomenology · Physics 2010-04-06 William H. Kinney , Edward W. Kolb , Alessandro Melchiorri , Antonio Riotto

We present limits to the amplitude of non-Gaussian primordial fluctuations in the WMAP 1-year cosmic microwave background sky maps. A non-linear coupling parameter, f_NL, characterizes the amplitude of a quadratic term in the primordial…

The anisotropy of the cosmic microwave background radiation contains information about the contents and history of the universe. We report new limits on cosmological parameters derived from the angular power spectrum measured in the first…

We present cosmological parameter constraints based on the final nine-year WMAP data, in conjunction with additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter LCDM…

Recent analysis of the WMAP and Planck data have shown the presence of a dip and a bump in the spectrum of primordial perturbations at the scales $k=0.002$ Mpc${}^{-1}$ and $k=0.0035$ Mpc${}^{-1}$ respectively. We analyze for the first time…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Alexander Gallego Cadavid , Antonio Enea Romano , Stefano Gariazzo

In this addendum to Phys.Rev. D74 (2006) 023502, we present an update of cosmological constraints on single-field inflation in light of the Wilkinson Microwave Ansiotropy Probe satellite mission five-year results (WMAP5). We find that the…

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