Inflation models after WMAP year three

Alabidi, Laila; Lyth, David H.

doi:10.1088/1475-7516/2006/08/013

Cited by 72 publications

(97 citation statements)

References 60 publications

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“…1, we see that the brane inflation model is consistent with the WMAP data within some range of N. On the other hand, it has been proposed in [21] that the e-folding number relevant to observations should be So, we shall check whether the fitting of WMAP five-year data can give a reasonable e-folding number consistent with the result of (13), namely, 47 < N < 61. Table I is the result of the fitting to the WMAP data (combined with other observational data) for the number of e-folds N. It is clear to see that the fitting values of the e-folding number are generally consistent with the result of [21], N = 47 ∼ 61, within 1σ range.…”

Section: A General Brane Inflation Modelmentioning

confidence: 52%

Brane inflation revisited after WMAP five-year results

Zhang

2009

J. Cosmol. Astropart. Phys.

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In this paper, we revisit brane inflation models with the WMAP five-year results.The WMAP five-year data favor a red-tilted power spectrum of primordial fluctuations at the level of two standard deviations, which is the same as the WMAP three-year result qualitatively, but quantitatively the spectral index is slightly greater than the three-year value. This result can bring impacts on brane inflation models.According to the WMAP five-year data, we find that the KKLMMT model can survive at the level of one standard deviation, and the fine-tuning of the parameter β can be alleviated to a certain extent at the level of two standard deviations.

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Section: A General Brane Inflation Modelmentioning

confidence: 52%

Brane inflation revisited after WMAP five-year results

Zhang

2009

J. Cosmol. Astropart. Phys.

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“…Assuming each of the ranges is uniform, we establish [ǫ(N ), ℓ λ H (N )]. We require that inflation last between 46 and 67 e-folds, roughly consistent with known constraints [30,31]. With ǫ(N ), we also solve for the relation between φ and N and between φ and k.…”

Section: A Monte-carlo Reconstruction Of Inflationary Flowsmentioning

confidence: 98%

WMAP-normalized inflationary model predictions and the search for primordial gravitational waves with direct detection experiments

2006

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In addition to density perturbations, inflationary models of the early universe generally predict a stochastic background of gravitational waves or tensor fluctuations. By making use of the inflationary flow approach for single field models and fitting the models with Monte-Carlo techniques to cosmic microwave background (CMB) data from the Wilkinson Microwave Anisotropy Probe (WMAP), we discuss the expected properties of the gravitational wave background from inflation at scales corresponding to direct detection experiments with laser interferometers in space. We complement the Monte-Carlo numerical calculations by including predictions expected under several classes of analytical inflationary models. We find that an improved version of Big Bang Observer (BBOgrand) can be used to detect a gravitational wave background at 0.1 Hz with a corresponding CMB tensor-to-scalar ratio above 10 −4 . Even if the CMB tensor-to-scalar ratio were to be above 10 −2 , we suggest that BBO-grand will be useful to study inflationary models as the standard version of BBO, with a sensitivity to a stochastic gravitational wave background ΩGWh 2 > 10 −17 , will only allow a marginal detection of the amplitude while leaving the tensor spectral index at 0.1 Hz unconstrained. Also, inflationary models with a large tensor-to-scalar ratio predict a substantial negative tensor spectral index such that the gravitational wave amplitude is damped at direct detection frequencies. We also discuss the extent to which CMB measurements can be used to predict the gravitational wave background amplitude in a direct detection experiment and how any measurement of the amplitude and the spectral tilt of the gravitational wave background at direct detection frequencies together with the CMB tensor-to-scalar ratio can be used to establish slow-roll inflation.

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“…Even earlier analyses [31,32] placed observational constraints on this model using COBE data [33]. Other papers have studied inflation models (including NI) in light of the WMAP1 and WMAP3 data [15,34] and in light of Planck data [35].…”

Section: Introductionmentioning

confidence: 99%

Natural inflation: consistency with cosmic microwave background observations of Planck and BICEP2

Freese

Kinney

2015

J. Cosmol. Astropart. Phys.

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Natural inflation is a good fit to all cosmic microwave background (CMB) data and may be the correct description of an early inflationary expansion of the Universe. The large angular scale CMB polarization experiment BICEP2 has announced a major discovery, which can be explained as the gravitational wave signature of inflation, at a level that matches predictions by natural inflation models. The natural inflation (NI) potential is theoretically exceptionally well motivated in that it is naturally flat due to shift symmetries, and in the simplest version takes the formA tensor-to-scalar ratio r > 0.1 as seen by BICEP2 requires the height of any inflationary potential to be comparable to the scale of grand unification and the width to be comparable to the Planck scale. The Cosine Natural Inflation model agrees with all cosmic microwave background measurements as long as f > ∼ m Pl (where m Pl = 1.22 × 10 19 GeV) and Λ ∼ mGUT ∼ 10 16 GeV. This paper also discusses other variants of the natural inflation paradigm: we show that axion monodromy with potential V ∝ φ 2/3 is inconsistent with the BICEP2 limits at the 95% confidence level, and low-scale inflation is strongly ruled out. Linear potentials V ∝ φ are inconsistent with the BICEP2 limit at the 95% confidence level, but are marginally consistent with a joint Planck/BICEP2 limit at 95%. We discuss the pseudo-Nambu Goldstone model proposed by Kinney and Mahanthappa as a concrete realization of low-scale inflation. While the low-scale limit of the model is inconsistent with the data, the large-field limit of the model is marginally consistent with BICEP2. All of the models considered predict negligible running of the scalar spectral index, and would be ruled out by a detection of running.

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Inflation models after WMAP year three

Abstract: The survey of models in astro-ph/0510441 is updated. For the first time, a large fraction of the models is ruled out at more than 3σ.

Cited by 72 publications

References 60 publications

Brane inflation revisited after WMAP five-year results

Brane inflation revisited after WMAP five-year results

WMAP-normalized inflationary model predictions and the search for primordial gravitational waves with direct detection experiments

Natural inflation: consistency with cosmic microwave background observations of Planck and BICEP2

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