Search for features in the spectrum of primordial perturbations using Planck and other datasets

Hunt, P. M.; Sarkar, S.

doi:10.1088/1475-7516/2015/12/052

Cited by 42 publications

(33 citation statements)

References 108 publications

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“…As is well-known, the recent data from Planck and WMAP reveal that there is suppression of power in the temperature anisotropy spectrum C TT at angular scales 30, with statistical significance of approximately 2-3σ [35,[61][62][63]. The key question then is whether the theoretical power spectra of Fig.…”

Section: Remarksmentioning

confidence: 99%

Quantum gravity in the sky: interplay between fundamental theory and observations

Ashtekar

Gupt

2016

Class. Quantum Grav.

186

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Observational missions have provided us with a reliable model of the evolution of the universe starting from the last scattering surface all the way to future infinity. Furthermore given a specific model of inflation, using quantum field theory on curved space-times this history can be pushed back in time to the epoch when space-time curvature was some 10 62 times that at the horizon of a solar mass black hole! However, to extend the history further back to the Planck regime requires input from quantum gravity. An important aspect of this input is the choice of the background quantum geometry and of the Heisenberg state of cosmological perturbations thereon, motivated by Planck scale physics. This paper introduces first steps in that direction. Specifically we propose two principles that link quantum geometry and Heisenberg uncertainties in the Planck epoch with late time physics and explore in detail the observational consequences of the initial conditions they select. We find that the predicted temperature-temperature (T-T) correlations for scalar modes are indistinguishable from standard inflation at small angular scales even though the initial conditions are now set in the deep Planck regime. However, there is a specific power suppression at large angular scales. As a result, the predicted spectrum provides a better fit to the PLANCK mission data than standard inflation, where the initial conditions are set in the general relativity regime. Thus, our proposal brings out a deep interplay between the ultraviolet and the infrared. Finally, the proposal also leads to specific predictions for power suppression at large angular scales also for the (T-E and E-E) correlations involving electric polarization. The PLANCK team is expected to release this data in the coming year.

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Section: Remarksmentioning

confidence: 99%

Quantum gravity in the sky: interplay between fundamental theory and observations

Ashtekar

Gupt

2016

Class. Quantum Grav.

186

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“…The latest Planck results marginally support the existence of deviations from scale-invariance localised at different multipoles in the angular power spectrum [59][60][61], that could be due to features in the primordial power spectrum. Features in the primordial spectra are excesses over the ΛCDM line, very much like the bumps over the standard model background seen in the LHC data.…”

Section: Introductionmentioning

confidence: 96%

Constraints on inflation with LSS surveys: features in the primordial power spectrum

Palma

Sapone

Sypsas

2018

J. Cosmol. Astropart. Phys.

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We analyse the efficiency of future large scale structure surveys to unveil the presence of scale dependent features in the primordial spectrum -resulting from cosmic inflation-imprinted in the distribution of galaxies. Features may appear as a consequence of non-trivial dynamics during cosmic inflation, in which one or more background quantities experienced small but rapid deviations from their characteristic slow-roll evolution. We consider two families of features: localised features and oscillatory extended features. To characterise them we employ various possible templates parametrising their scale dependence and provide forecasts on the constraints on these parametrisations for LSST like surveys. We perform a Fisher matrix analysis for three observables: cosmic microwave background (CMB), galaxy clustering and weak lensing. We find that the combined data set of these observables will be able to limit the presence of features down to levels that are more restrictive than current constraints coming from CMB observations only. In particular, we address the possibility of gaining information on currently known deviations from scale invariance inferred from CMB data, such as the feature appearing at the ℓ ∼ 20 multipole (which is the main contribution to the low-ℓ deficit) and another one around ℓ ∼ 800.

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“…The starting point of our work is a previously estimated PPS. It was recovered from the Planck Public Release 2 temperature and polarisation data using Tikhonov regularisation penalising first-order derivatives 9 of the PPS, as explained in detail in [31]. The Planck T T , T E and EE likelihood function consists of a pixel-based component for multpoles ≤ 29 and a Gaussian pseudo-C component for 30 ≤ ≤ 2508.…”

Section: Reconstructing the Eft Parametersmentioning

confidence: 99%

Reconstructing the EFT of inflation from cosmological data

Durakovic

Hunt²,

Patil³

et al. 2019

SciPost Phys.

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Reconstructions of the primordial power spectrum (PPS) of curvature perturbations from cosmic microwave background anisotropies and large-scale structure data suggest that the usually assumed power-law PPS has localised features (up to ∼ 10% in amplitude), although of only marginal significance in the framework of ΛCDM cosmology. On the other hand if the cosmology is taken to be Einstein-de Sitter, larger features in the PPS (up to ∼ 20% in amplitude) are required to accurately fit the observed acoustic peaks. Within the context of single clock inflation, we show that any given reconstruction of the PPS can be mapped on to functional parameters of the underlying effective theory of the adiabatic mode within a 2ndorder formalism, provided the best fit fractional change of the PPS, ∆P R /P R is such that (∆P R /P R ) 3 falls within the 1 σ confidence interval of the reconstruction for features induced by variations of either the sound speed c s or the slow-roll parameter . Although there is a degeneracy amongst these functional parameters (and the models that project onto them), we can identify simple representative inflationary models that yield such features in the PPS. Thus we provide a dictionary (more accurately, a thesaurus) to go from observational data, via the reconstructed PPS, to models that reproduce them to per cent level precision.

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Search for features in the spectrum of primordial perturbations using Planck and other datasets

Cited by 42 publications

References 108 publications

Quantum gravity in the sky: interplay between fundamental theory and observations

Quantum gravity in the sky: interplay between fundamental theory and observations

Constraints on inflation with LSS surveys: features in the primordial power spectrum

Reconstructing the EFT of inflation from cosmological data

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