Effects of particle production during inflation

Romano, Antonio Enea; Sasaki, Misao

doi:10.1103/physrevd.78.103522

Cited by 85 publications

(122 citation statements)

References 14 publications

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“…We use four separate P k templates to generate the C ℓ s. The first is a standard power law with n s = 0.96 but with a lower amplitude than the best-fit, the second is a running n s model with dn s /d ln k = −0.037, the third is a power law with a sharp, compensated feature at k = 0.02 Mpc −1 [4,7,8,10,14,15,16,17] and the fourth is a power law with superimposed sinusoidal oscillations [5,9,18,60,61]. The extended estimator is run on all four sets of C ℓ forecasts and the resulting P k solution is compared to the input one.…”

Section: Application Of the Extended Rl Estimator A Tests On Fomentioning

confidence: 99%

“…Current limits on this parametrisation place the spectral index n s ≈ 0.963 [3]. More complex inflationary models such as those with features on the potential [4,5,6,7,8,9,10], a small number of e-folds [11,12,13], or other exotic inflationary models [14,15,16,17,18] can modify P (k) in a manner not compatible with the simple power law description. There have been many parametric searches for the features produced by these models [11,19,20,21,22,23,24,25,26,27,28], although none have proved conclusive.…”

Section: Introductionmentioning

confidence: 99%

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Reconstruction of the primordial power spectrum using temperature and polarisation data from multiple experiments

Nicholson

Contaldi

2009

J. Cosmol. Astropart. Phys.

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We develop a method to reconstruct the primordial power spectrum, P (k), using both temperature and polarisation data from the joint analysis of a number of Cosmic Microwave Background (CMB) observations. The method is an extension of the Richardson-Lucy algorithm, first applied in this context by Shafieloo & Souradeep [1]. We show how the inclusion of polarisation measurements can decrease the uncertainty in the reconstructed power spectrum. In particular, the polarisation data can constrain oscillations in the spectrum more effectively than total intensity only measurements. We apply the estimator to a compilation of current CMB results. The reconstructed spectrum is consistent with the best-fit power spectrum although we find evidence for a 'dip' in the power on scales k ≈ 0.002 Mpc −1 . This feature appears to be associated with the WMAP power in the region 18 ≤ ℓ ≤ 26 which is consistently below best-fit models. We also forecast the reconstruction for a simulated, Planck-like [2] survey including sample variance limited polarisation data.

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Section: Application Of the Extended Rl Estimator A Tests On Fomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reconstruction of the primordial power spectrum using temperature and polarisation data from multiple experiments

Nicholson

Contaldi

2009

J. Cosmol. Astropart. Phys.

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“…Because these theories generically predict the existence of a large number of degrees of freedom, the need of a period of inflation at early times is found to impose strong restrictions on their interactions. In particular, if inflation happened at sufficiently high energies, curvature perturbations could have strongly interacted with other degrees of freedom, implying a variety of observable effects departing from those predicted in standard single-field slow-roll inflation [12][13][14], including features in the power spectrum of primordial inhomogeneities [15][16][17][18][19][20][21][22][23][24][25][26][27][28], large primordial non-Gaussianities [29][30][31][32][33][34][35] and isocurvature perturbations [36][37][38][39][40][41][42][43][44]. A detection of any of these signatures would therefore represent an extremely significant step towards elucidating the fundamental nature of physics taking place during the very early universe.…”

Section: Introductionmentioning

confidence: 99%

On the importance of heavy fields during inflation

Céspedes

Atal

Palma

2012

J. Cosmol. Astropart. Phys.

140

207

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We study the dynamics of two-field models of inflation characterized by a hierarchy of masses between curvature and isocurvature modes. When the hierarchy is large, a low energy effective field theory (EFT) exists in which only curvature modes participate in the dynamics of perturbations. In this EFT heavy fields continue to have a significant role in the low energy dynamics, as their interaction with curvature modes reduces their speed of sound whenever the multi-field trajectory is subject to a sharp turn in target space. Here we analyze under which general conditions this EFT remains a reliable description for the linear evolution of curvature modes. We find that the main condition consists on demanding that the rate of change of the turn's angular velocity stays suppressed with respect to the masses of heavy modes. This adiabaticity condition allows the EFT to accurately describe a large variety of situations in which the multi-field trajectory is subject to sharp turns. To test this, we analyze several models with turns and show that, indeed, the power spectra obtained for both the original two-field theory and its single-field EFT are identical when the adiabaticity condition is satisfied. In particular, when turns are sharp and sudden, they are found to generate large features in the power spectrum, accurately reproduced by the EFT.arXiv:1201.4848v3 [hep-th]

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“…Indeed, the idea was originally introduced [44] as a means for reheating after inflation. Since [35] subsequent work [45][46][47][48] has elaborated on the basic scheme into a model with coupling between two scalar fields. Here, we summarize essential features of the canonical single fermion field coupled to the inflaton as a means to clarify the possible physics of the = 10 − 30 dip.…”

Section: Resonant Particle Production During Inflationmentioning

confidence: 99%

Possible evidence for Planck-scale resonant particle production during inflation from the CMB power spectrum

Mathews¹,

Gangopadhyay²,

Ichiki³

et al. 2015

Phys. Rev. D

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The power spectrum of the cosmic microwave background from both the Planck and WMAP data exhibits a slight dip for multipoles in the range of l = 10 − 30. We show that such a dip could be the result of the resonant creation of massive particles that couple to the inflaton field. For our best-fit models, the epoch of resonant particle creation reenters the horizon at a wave number of k * ∼ 0.00011 ± 0.0004 (h Mpc −1 ). The amplitude and location of this feature corresponds to the creation of a number of degenerate fermion species of mass ∼ (8 − 11)/λ 3/2 m pl during inflation where λ ∼ (1.0 ± 0.5)N −2/5 is the coupling constant between the inflaton field and the created fermion species, while N is the number of degenerate species. Although the evidence is of marginal statistical significance, this could constitute new observational hints of unexplored physics beyond the Planck scale.

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Effects of particle production during inflation

Cited by 85 publications

References 14 publications

Reconstruction of the primordial power spectrum using temperature and polarisation data from multiple experiments

Reconstruction of the primordial power spectrum using temperature and polarisation data from multiple experiments

On the importance of heavy fields during inflation

Possible evidence for Planck-scale resonant particle production during inflation from the CMB power spectrum

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