On the scalar consistency relation away from slow roll

Vijayakumar, S.; Hazra, Dhiraj Kumar; Sriramkumar, L.

doi:10.1088/1475-7516/2015/02/029

Cited by 41 publications

(46 citation statements)

References 179 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Whenever a theory admits one or more gauge symmetries (SU (3) c in the case of QCD for example), one must also a priori allow for the possibility of xlii In addition to generating potentially observable tensor non-Gaussianties over a limited range of scales [170][171][172].…”

Section: Effective Potential Modulations and Phase Transitionsmentioning

confidence: 99%

Features and new physical scales in primordial observables: Theory and observation

Chluba

Hamann

Patil

2015

Int. J. Mod. Phys. D

208

233

View full text Add to dashboard Cite

June 22, 20152 All cosmological observations to date are consistent with adiabatic, Gaussian and nearly scale invariant initial conditions. These findings provide strong evidence for a particular symmetry breaking pattern in the very early universe (with a close to vanishing order parameter, ), widely accepted as conforming to the predictions of the simplest realizations of the inflationary paradigm. However, given that our observations are only privy to perturbations, in inferring something about the background that gave rise to them, it should be clear that many different underlying constructions project onto the same set of cosmological observables. Features in the primordial correlation functions, if present, would offer a unique and discriminating window onto the parent theory in which the mechanism that generated the initial conditions is embedded. In certain contexts, simple linear response theory allows us to infer new characteristic scales from the presence of features that can break the aforementioned degeneracies among different background models, and in some cases can even offer a limited spectroscopy of the heavier degrees of freedom that couple to the inflaton. In this review, we offer a pedagogical survey of the diverse, theoretically well grounded mechanisms which can imprint features into primordial correlation functions in addition to reviewing the techniques one can employ to probe observations. These observations include cosmic microwave background anisotropies and spectral distortions as well as the matter two and three point functions as inferred from large-scale structure and potentially, 21 cm surveys.

show abstract

Section: Effective Potential Modulations and Phase Transitionsmentioning

confidence: 99%

Features and new physical scales in primordial observables: Theory and observation

Chluba

Hamann

Patil

2015

Int. J. Mod. Phys. D

208

233

View full text Add to dashboard Cite

show abstract

“…As we have pointed out before, the WWI essentially generates same power spectra as generated by Starobinsky-1992 model of inflation with a spectral tilt of ∼ 0.96. The bispectra generated from this model, hence are of same shape as discussed in literature [38,[49][50][51][52]. To evaluate the f NL from the WWI model we have used a Theta function and Delta function with a width similar to WWI-d model, to reproduce the effects of the singularity in the second derivative of the potential.…”

Section: Non-gaussianitymentioning

confidence: 99%

Primordial features and Planck polarization

Hazra

Shafieloo

Smoot

et al. 2016

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract. With the Planck 2015 Cosmic Microwave Background (CMB) temperature and polarization data, we search for possible features in the primordial power spectrum (PPS). We revisit the Wiggly Whipped Inflation (WWI) framework and demonstrate how generation of some particular primordial features can improve the fit to Planck data. WWI potential allows the scalar field to transit from a steeper potential to a nearly flat potential through a discontinuity either in potential or in its derivatives. WWI offers the inflaton potential parametrizations that generate a wide variety of features in the primordial power spectra incorporating most of the localized and non-local inflationary features that are obtained upon reconstruction from temperature and polarization angular power spectrum. At the same time, in a single framework it allows us to have a background parameter estimation with a nearly free-form primordial spectrum. Using Planck 2015 data, we constrain the primordial features in the context of Wiggly Whipped Inflation and present the features that are supported both by temperature and polarization. WWI model provides more than 13 improvement in χ 2 fit to the data with respect to the best fit power law model considering combined temperature and polarization data from Planck and B-mode polarization data from BICEP and Planck dust map. We use 2-4 extra parameters in the WWI model compared to the featureless strict slow roll inflaton potential. We find that the differences between the temperature and polarization data in constraining background cosmological parameters such as baryon density, cold dark matter density are reduced to a good extent if we use primordial power spectra from WWI. We also discuss the extent of bispectra obtained from the best potentials in arbitrary triangular configurations using the BI-spectra and Non-Gaussianity Operator (BINGO).

show abstract

“…Therefore, in the squeezed limit, the three-point function can be completely expressed in terms of the two-point function through a relation referred to as the consistency condition (see Refs. [75][76][77][78][79][80][81] in the context of three-point functions involving scalar and tensor perturbations, and Refs. [71,72] for cross-correlations between the scalar perturbation and the magnetic fields).…”

Section: Introductionmentioning

confidence: 99%

Cross-correlations between scalar perturbations and magnetic fields in bouncing universes

Chowdhury

Sriramkumar

Kamionkowski

2019

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

Bouncing scenarios offer an alternative to the inflationary paradigm for the generation of perturbations in the early universe. Recently, there has been a surge in interest in examining the issue of primordial magnetogenesis in the context of bouncing universes. As in the case of inflation, the conformal invariance of the electromagnetic action needs to be broken in bouncing scenarios in order to generate primordial magnetic fields which correspond to observed strengths today. The non-minimal coupling, which typically depends on a scalar field that possibly drives the homogeneous background, leads to a cross-correlation at the level of the three-point function between the perturbation in the scalar field and the magnetic fields. This has been studied in some detail in the context of inflation and, specifically, it has been established that the three-point function satisfies the so-called consistency relation in the squeezed limit. In this work, we study the cross-correlation between the magnetic fields and the perturbation in an auxiliary scalar field in a certain class of bouncing scenarios. We consider couplings that lead to scale invariant spectra of the magnetic field and evaluate the corresponding cross-correlation between the magnetic field and the perturbation in the scalar field. We find that, when compared to de Sitter inflation, the dimensionless non-Gaussianity parameter that characterizes the amplitude of the cross-correlations proves to be considerably larger in bouncing scenarios. We also show that the aforementioned consistency condition governing the cross-correlation is violated in the bouncing models. We discuss the implications of our results.

show abstract

On the scalar consistency relation away from slow roll

Cited by 41 publications

References 179 publications

Features and new physical scales in primordial observables: Theory and observation

Features and new physical scales in primordial observables: Theory and observation

Primordial features and Planck polarization

Cross-correlations between scalar perturbations and magnetic fields in bouncing universes

Contact Info

Product

Resources

About