First‐Year
                    <i>Wilkinson Microwave Anisotropy Probe</i>
                    (
                    <i>WMAP</i>
                    ) Observations: Determination of Cosmological Parameters

Abstract. We set up cosmological perturbation theory and study the cosmological implications of the so-called "generalized Galileon" developed in [6, 7]. This is the most general scalar field theory whose Lagrangian contains derivatives up to second order while keeping second order equations of motion, and contains as sub-cases k-inflation, G-inflation and many other models. We calculate the power spectrum of the primordial curvature perturbation, finding a modification of the usual consistency relation of the tensor-to-scalar ratio in k-inflation or perfect fluid models. Finally we also calculate the bispectrum, which contains no new shapes beyond those of k-inflation.

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“…Finally, one may be interested in evaluating the dimensionless non-linear parameters, defined by [43] f…”

Section: Bispectrum Of the Curvature Perturbationmentioning

confidence: 99%

Inflation and primordial non-Gaussianities of “generalized Galileons”

Gao

Steer

2011

J. Cosmol. Astropart. Phys.

121

141

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“…From the phenomenological viewpoint, it is important to constrain the effective equation of state of dark energy w by observations. Even though we have obtained the constraint as w < −0.78 (95 % confidence limit assuming w ≥ −1) [11] by combining WMAP data with other astronomical data, to pin down the value of w, it is Figure 7. The dispersion of the density distribution in several dark energy models (R = 2h −1 Mpc).…”

Section: Discussionmentioning

confidence: 99%

“…Combining measurements of Cosmic Microwave Background Radiation [9] and recent galaxy redshift survey [10], we are forced to recognize the existence of a cosmological constant, or kind of dark energy whose value is almost the same order of magnitude as the present density of the Universe [11]. (For reviews about the cosmological constant problem, see [12].)…”

Section: Introductionmentioning

confidence: 99%

Non-Gaussianity of the density distribution in accelerating universes: II.N-body simulations

Tatekawa

Mizuno

2007

J. Cosmol. Astropart. Phys.

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Abstract. We explore the possibility of putting constraints on dark energy models with statistical property of large scale structure in the non-linear region. In particular, we investigate the w dependence of non-Gaussianity of the smoothed density distribution generated by the nonlinear dynamics. In order to follow the non-linear evolution of the density fluctuations, we apply N-body simulations based on P 3 M scheme. We show that the relative difference between non-Gaussianity of w = −0.8 model and that of w = −1.0 model is 1.1% (skewness) and 5.3% (kurtosis) for R = 8h −1 Mpc. We also calculate the correspondent quantities for R = 2h −1 Mpc, 4.4% (skewness) and 13.4% (kurtosis), and the difference turn out to be greater, even though non-linearity in this scale is so strong that the complex physical processes about galaxy formation affect the galaxy distribution. From this, we can expect that the difference can be tested by weak lensing surveys with the help of the convergence field, which suggests that non-Gaussianity of the density distribution potentially plays an important role for extracting information on dark energy. PACS numbers: 02.60. Cb, 45.50.Jf, 95.36.+x, 98.65.Dx

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“…This number was determined with accurate measurements of the CMB radiation by the experiments WMAP [5] and Planck [6]. However, there is no experimental evidence for primordial antimatter in the visible universe.…”

Section: Theoretical Motivations For Lorentz and Cpt Violationmentioning

confidence: 99%

Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016)

Hiyama¹,

Kanai²,

Ulmer

et al. 2017

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I review briefly string-inspired models of the Early Universe in which the Robertson-Walker geometry is extended to involve appropriate torsion fields that are constant in the frame of a cosmological observer. Fermion fields in such geometries are described by Lagrangians that fall in the simplest Lorentz-and CPT-violating extensions of the Standard Model (SME), in which the fermions couple to a constant axial vector background b µ γ 5 , with the b µ "axion-like" field associated to torsion. In the talk I also review mechanisms to suppress the torsion in the current era, compatible with the existing stringent upper bounds, which are of relevance to searches for CPT violation of interest to this conference. KEYWORDS:Early Universe, Torsion, Strings, Standard Model Extension, CPT Violation Theoretical motivations for Lorentz and CPT ViolationBaryogenesis/Leptogenesis, that is processes in the early Universe that lead to the observed matter-antimatter asymmetry in the Cosmos, represent a long-standing unresolved issue in cosmology [1]. Many approaches to the problem proposed in the literature [2] but no consensus has emerged on the potential mechanisms. Many of them predict lepton number violation, and in particular some of them entail [3] a µ → e − γ interaction with predictions on the corresponding branching ratio which may be falsified at the next generation experiments, but others are more difficult to falsify.A standard measure of the abundance of baryons over that of antibaryons is defined by the ratiowhere n B is the number density of baryons, nB is the number density of antibaryons and n γ is the density of photons (proportional to the entropy density s). This number was determined with accurate measurements of the CMB radiation by the experiments WMAP [5] and Planck [6]. However, there is no experimental evidence for primordial antimatter in the visible universe. Similarly, the generation of an asymmetry between leptons and antileptons is known as leptogenesis. This is expected to be of the same order of magnitude as Y ∆B . If B, the net baryon number, is conserved in Nature, the matter asymmetry can only originate from an asymmetric initial condition B 0. However, such an asymmetry would rapidly diminish during inflation, and extreme fine tuning of the initial condition would become necessary. This is highly unsatisfactory from a theoretical point of view. Consequently a mechanism for the dynamical generation of a baryon asymmetry is required. In the seminal paper [7], Sakharov identified three sufficient conditions that must be satisfied in order to produce a net baryon number.(1) The theory must allow for interactions that violate B conservation. These interactions must become effective at high energy scales in order to guarantee the stability of the proton. (2) Both discrete symmetries C (charge conjugation) and CP (where P denotes parity) are violated.In fact C violation is not enough, as correlations between the spins of particles and antiparticles 1

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First‐Year Wilkinson Microwave Anisotropy Probe ( WMAP ) Observations: Determination of Cosmological Parameters

Cited by 9,727 publications

References 123 publications

Inflation and primordial non-Gaussianities of “generalized Galileons”

Inflation and primordial non-Gaussianities of “generalized Galileons”

Non-Gaussianity of the density distribution in accelerating universes: II.N-body simulations

Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016)

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