scholarly journals Unlocking the synergy between CMB spectral distortions and anisotropies

2021 ◽  
Vol 2021 (12) ◽  
pp. 050
Author(s):  
Hao Fu ◽  
Matteo Lucca ◽  
Silvia Galli ◽  
Elia S. Battistelli ◽  
Deanna C. Hooper ◽  
...  
Keyword(s):  
Spectral Index ◽  
Big Bang ◽  
Noise Levels ◽  
Microwave Background ◽  
Big Bang Nucleosynthesis ◽  
Scalar Spectral Index ◽  
New Information ◽  
Wide Range ◽  
Inflationary Parameters ◽  
Better Than

Abstract Measurements of the cosmic microwave background (CMB) spectral distortions (SDs) will open a new window on the very early universe, providing new information complementary to that gathered from CMB temperature and polarization anisotropies. In this paper, we study their synergy as a function of the characteristics of the considered experiments. In particular, we examine a wide range of sensitivities for possible SD measurements, spanning from FIRAS up to noise levels 1000 times better than PIXIE, and study their constraining power when combined with current or future CMB anisotropy experiments such as Planck or LiteBIRD plus CMB-S4. We consider a number of different cosmological models such as the ΛCDM, as well as its extensions with the running of the scalar spectral index, the decay or the annihilation of dark matter (DM) particles. While upcoming CMB anisotropy experiments will be able to decrease the uncertainties on inflationary parameters such as As and ns by about a factor 2 in the ΛCDM case, we find that an SD experiment 100 times more sensitive than PIXIE (comparable to the proposed Super-PIXIE satellite) could potentially further contribute to constrain these parameters. This is even more significant in the case of the running of the scalar spectral index. Furthermore, as expected, constraints on DM particles decaying at redshifts probed by SDs will improve by orders of magnitude even with an experiment 10 times worse than PIXIE as compared to CMB anisotropies or Big Bang Nucleosynthesis bounds. On the contrary, DM annihilation constraints will not significantly improve over CMB anisotropy measurements. Finally, we forecast the constraints obtainable with sensitivities achievable either from the ground or from a balloon.

scholarly journals A new tension in the cosmological model from primordial deuterium?

2021 ◽  
Vol 502 (2) ◽  
pp. 2474-2481
Author(s):  
Cyril Pitrou ◽  
Alain Coc ◽  
Jean-Philippe Uzan ◽  
Elisabeth Vangioni
Keyword(s):  
Big Bang ◽  
Reaction Cross ◽  
Light Elements ◽  
Neutron Lifetime ◽  
Microwave Background ◽  
Big Bang Nucleosynthesis ◽  
Baryonic Density ◽  
The Status ◽  
Big Bang Model ◽  
The Big Bang

ABSTRACT Recent measurements of the D(p,γ)3He nuclear reaction cross-section and of the neutron lifetime, along with the reevaluation of the cosmological baryon abundance from cosmic microwave background (CMB) analysis, call for an update of abundance predictions for light elements produced during the big-bang nucleosynthesis (BBN). While considered as a pillar of the hot big-bang model in its early days, BBN constraining power mostly rests on deuterium abundance. We point out a new ≃1.8σ tension on the baryonic density, or equivalently on the D/H abundance, between the value inferred on one hand from the analysis of the primordial abundances of light elements and, on the other hand, from the combination of CMB and baryonic oscillation data. This draws the attention on this sector of the theory and gives us the opportunity to reevaluate the status of BBN in the context of precision cosmology. Finally, this paper presents an upgrade of the BBN code primat.

Reconstruction of warm Chaplygin gas inflationary models

2020 ◽  
Vol 35 (32) ◽  
pp. 2050268
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Kazuharu Bamba ◽  
Nadeem Azhar
Keyword(s):  
Spectral Index ◽  
Effective Potential ◽  
Chaplygin Gas ◽  
Index Formula ◽  
Curvature Perturbation ◽  
Warm Inflation ◽  
Scalar Spectral Index ◽  
Dissipative Coefficient ◽  
Inflationary Parameters ◽  
Friedmann Robertson Walker

By assuming the specific Chaplygin gas model, we study the reconstruction of warm inflation model with the help of tensor-to-scalar ratio [Formula: see text] and scalar spectral index [Formula: see text]. In this regard, we take flat Friedmann–Robertson–Walker (FRW) metric and discuss the general forms of dissipative coefficient [Formula: see text] as well as effective potential [Formula: see text] for two dissipative regimes i.e., the weak and strong. We use inflationary parameters such as slow-roll parameters, power spectrum of the curvature perturbation, tensor spectrum, spectral index, scalar-to-tensor ratio and Hubble parameter to find the generalized form of dissipative coefficient and effective potential. We discuss the results of dissipative coefficient and reconstructed potential in detail for the specific choice of tensor-to-scalar ratio [Formula: see text] and scalar spectral index [Formula: see text].

New constraint of an attractor GL model in braneworld context

2017 ◽  
Vol 32 (19n20) ◽  
pp. 1750119
Author(s):  
Z. Mounzi ◽  
A. Safsafi ◽  
M. Ferricha-Alami ◽  
M. Bennai
Keyword(s):  
Power Spectrum ◽  
Spectral Index ◽  
Index Formula ◽  
Brane Tension ◽  
Inflation Model ◽  
Scalar Spectral Index ◽  
Central Value ◽  
Braneworld Model ◽  
Inflationary Parameters

We are interested in studying the generalization of the first chaotic inflation model in supergravity, which was proposed by Goncharov and Linde (GL model) and was recently revisited, in the framework of the Randall–Sundrum type 2 braneworld model. This model predicts a tiny ratio [Formula: see text] and [Formula: see text]. Our scenario predicts a great tensor-to-scalar ratio [Formula: see text] of the order [Formula: see text] and the central value of the scalar spectral index [Formula: see text] for a particular choice of values of brane tension [Formula: see text] and the parameter [Formula: see text]. We have shown that this scenario reproduces successfully an attractor behavior. We have also derived all known spectrum inflationary parameters, in particular the running [Formula: see text] and the power spectrum of the curvature perturbations [Formula: see text] which are widely consistent with Planck observations.

Shaft potential inspired warm inflation

2017 ◽  
Vol 14 (06) ◽  
pp. 1750088 ◽  
Author(s):  
Abdul Jawad ◽  
Amara Ilyas ◽  
Sarfraz Ahmad
Keyword(s):  
Scalar Field ◽  
Spectral Index ◽  
Power Spectra ◽  
Spectral Indices ◽  
Tensor Power ◽  
Planck Data ◽  
Warm Inflation ◽  
Slow Roll ◽  
Scalar Spectral Index ◽  
Inflationary Parameters

We discuss the warm inflation in the presence of shaft potential [Formula: see text], tachyon scalar field and the generalized form of dissipative coefficient [Formula: see text]. In this respect, we investigate the inflationary parameters (slow-roll parameters, number of e-folds, scalar-tensor power spectra, spectral indices, tensor-to-scalar ratio and running of scalar spectral index) in both strong and weak dissipative regimes. It is interesting to mention that our inflationary parametric results (tensor-scalar ratio, spectral index and running of spectral) are consistent with the recent observational data such as BICEP[Formula: see text], WMAP[Formula: see text] and latest Planck data.

scholarly journals Testing a Dilaton Gravity Model Using Nucleosynthesis

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
S. Boran ◽  
E. O. Kahya
Keyword(s):  
Steady State ◽  
Gravity Model ◽  
Big Bang ◽  
Universe Model ◽  
Light Elements ◽  
Dilaton Gravity ◽  
Microwave Background ◽  
Big Bang Nucleosynthesis ◽  
Higher Dimensional ◽  
State Universe

Big bang nucleosynthesis (BBN) offers one of the most strict evidences for theΛ-CDM cosmology at present, as well as the cosmic microwave background (CMB) radiation. In this work, our main aim is to present the outcomes of our calculations related to primordial abundances of light elements, in the context of higher dimensional steady-state universe model in the dilaton gravity. Our results show that abundances of light elements (primordial D,3He,4He, T, and7Li) are significantly different for some cases, and a comparison is given between a particular dilaton gravity model andΛ-CDM in the light of the astrophysical observations.

scholarly journals Nonminimal coupling inflation with constant slow roll

2021 ◽  
pp. 2150070
Author(s):  
Mehdi Shokri ◽  
Jafar Sadeghi ◽  
Mohammad Reza Setare ◽  
Salvatore Capozziello
Keyword(s):  
Scalar Field ◽  
Equations Of Motion ◽  
Nonminimal Coupling ◽  
Coupling Term ◽  
Microwave Background ◽  
First Order ◽  
Slow Roll ◽  
Wide Range ◽  
Single Field ◽  
Inflationary Parameters

In this paper, we study a single-field inflationary model modified by a nonminimal coupling term between the Ricci scalar [Formula: see text] and the scalar field [Formula: see text] in the context of constant-roll inflation. The first-order formalism is used to analyze the constant-roll inflation instead of the standard methods used in the literature. In principle, the formalism considers two functions of the scalar field, [Formula: see text] and [Formula: see text], which lead to the reduction of the equations of motion to first-order differential equations. The approach can be applied to a wide range of cosmological situations since it directly relates the function [Formula: see text] with Hubbles parameter [Formula: see text]. We perform the inflationary analysis for power-law and exponential couplings, separately. Then, we investigate the features of constant-roll potentials as inflationary potentials. Finally, we compare the inflationary parameters of the models with the observations of Cosmic Microwave Background (CMB) anisotropies in view of realizing a physically motivated model.

scholarly journals Analysis on the Evolution of the Effective Geff from Linear Nash-Green Fluctuations

2020 ◽  
Author(s):  
Abraao J.S. Capistrano ◽  
Luís A. Cabral ◽  
José A. P. F. Marão ◽  
Carlos H. Coimbra-Araújo
Keyword(s):  
Large Scale ◽  
Time Derivative ◽  
Extrinsic Curvature ◽  
Big Bang ◽  
Microwave Background ◽  
Big Bang Nucleosynthesis ◽  
Density Growth ◽  
Conformal Gauge ◽  
Newtonian Constant ◽  
Best Fit

From the linear Nash-Green fluctuations of background metric, we present the perturbation equations in an embedded four space-time. In the context of a five-dimensional bulk, we show that the perturbations are only propagated by the gravitational tensorial field equation. In a Newtonian conformal gauge, we study the matter density evolution in sub-horizon regime and on how such scale may be affected by the extrinsic curvature. We use the "extended Gold 2018'' growth dataset with 25 datapoints and the best fit Planck2018/LambdaCDM parameters. Hence, we determine the evolution equation for the density growth delta(a) as a result from the embedded equations of the background geometry. By using solar constraints, we analyse the evolution of the effective Newtonian constant Geff and showing that applying Taylor expansion to Geff (a) under the constraint of time-derivative of Geff(0)=G at a= 1 in matter domination era, we get an agreement with Big Bang Nucleosynthesis (BBN) and also an alleviation of the 3-sigma tension to 1-sigma contour between (sigma8-Omegam) of the observations from Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) probes.

Quartic potential inspired warm standard and tachyon scalar fields brane-world inflation

2017 ◽  
Vol 26 (13) ◽  
pp. 1750144 ◽  
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
Amara Ilyas
Keyword(s):  
Observational Data ◽  
Spectral Index ◽  
Scalar Fields ◽  
Current Data ◽  
Brane World ◽  
Inflationary Universe ◽  
Tachyon Field ◽  
Quartic Potential ◽  
Scalar Spectral Index ◽  
Inflationary Parameters

A warm inflationary universe in the brane-world scenario is being studied by assuming the standard scalar and tachyon field models. For this purpose, the quartic potential ([Formula: see text]) is being utilized which is ruled out by current data in cold inflation but in our models it is analyzed that it is in agreement with recent observational data. Moreover, the generalized form of dissipative coefficient [Formula: see text] is being considered. Within this setup, the inflationary parameters in the weak dissipative regime are being analyzed. It is observed that the ranges of our results of tensor-to-scalar ratio, scalar spectral index and running of spectral favor observational data like BICEP2, WMAP9 and Planck.

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