Angular correlation of the cosmic microwave background in the R h = ct Universe

2014

The Wilkinson Microwave Anisotropy Probe (WMAP) and Planck may have uncovered several anomalies in the full cosmic microwave background (CMB) sky that could indicate possible new physics driving the growth of density fluctuations in the early universe. These include an unusually low power at the largest scales and an apparent alignment of the quadrupole and octopole moments. In a LCDM model where the CMB is described by a Gaussian Random Field, the quadrupole and octopole moments should be statistically independent. The emergence of these low probability features may simply be due to posterior selections from many such possible effects, whose occurrence would therefore not be as unlikely as one might naively infer. If this is not the case, however, and if these features are not due to effects such as foreground contamination, their combined statistical significance would be equal to the product of their individual significances. In the absence of such extraneous factors, and ignoring the biasing due to posterior selection, the missing large-angle correlations would have a probability as low as ∼0.1% and the low-l multipole alignment would be unlikely at the ∼4.9% level; under the least favorable conditions, their simultaneous observation in the context of the standard model could then be likely at only the ∼0.005% level. In this paper, we explore the possibility that these features are indeed anomalous, and show that the corresponding probability of CMB multipole alignment in the = R ct h universe would then be ∼7-10%, depending on the number of large-scale Sachs-Wolfe induced fluctuations. Since the low power at the largest spatial scales is reproduced in this cosmology without the need to invoke cosmic variance, the overall likelihood of observing both of these features in the CMB is ⩾7%, much more likely than in LCDM, if the anomalies are real. The key physical ingredient responsible for this difference is the existence in the former of a maximum fluctuation size at the time of recombination, which is absent in the latter because of inflation.

Section: Large-scale Fluctuations In Thementioning

confidence: 99%

Section: Large-scale Fluctuations In Thementioning

confidence: 99%

Section: Large-scale Fluctuations In Thementioning

confidence: 99%

Section: Large-scale Fluctuations In Thementioning

confidence: 99%

See 2 more Smart Citations

Cosmological Implications of the CMB Large-Scale Structure

2014

“…Planck Collaboration XXIII 2014). But recent analyses of the two-point correlation function of the cosmic microwave background (Melia 2014;Copi et al 2015), as well as the Om(z i , z j ) and Omh 2 (z i , z j ) diagnostics applied to measurements of the Hubble expansion rate H(z) (Shafieloo, Sahni & Starobinsky 2012; Sahni, Shafieloo & Starobinsky 2014), appear to have revealed significant tension between its predictions and recent measurements (see, e.g. Zheng et al 2016).…”

mentioning

confidence: 99%

Analysing H(z) data using two-point diagnostics

Leaf

Monthly Notices of the Royal Astronomical Society

2017

Measurements of the Hubble constant H(z) are increasingly being used to test the expansion rate predicted by various cosmological models. But the recent application of two-point diagnostics, such as Om(z i , z j ) and Omh 2 (z i , z j ), has produced considerable tension between CDM's predictions and several observations, with other models faring even worse. Part of this problem is attributable to the continued mixing of truly model-independent measurements using the cosmic-chronometer approach, and model-dependent data extracted from baryon acoustic oscillations. In this paper, we advance the use of two-point diagnostics beyond their current status, and introduce new variations, which we call h(z i , z j ), that are more useful for model comparisons. But we restrict our analysis exclusively to cosmic-chronometer data, which are truly model independent. Even for these measurements, however, we confirm the conclusions drawn by earlier workers that the data have strongly non-Gaussian uncertainties, requiring the use of both 'median' and 'mean' statistical approaches. Our results reveal that previous analyses using two-point diagnostics greatly underestimated the errors, thereby misinterpreting the level of tension between theoretical predictions and H(z) data. Instead, we demonstrate that as of today, only Einstein-de Sitter is ruled out by the two-point diagnostics at a level of significance exceeding ∼3σ . The R h = ct universe is slightly favoured over the remaining models, including Lambda cold dark matter and Chevalier-Polarski-Linder, though all of them (other than Einstein-de Sitter) are consistent to within 1σ with the measured mean of the h(z i , z j ) diagnostics.Key words: galaxies: distances and redshifts -galaxies: evolution -large-scale structure of Universe -cosmology: observations -cosmology: theory. I N T RO D U C T I O NLambda cold dark matter ( CDM) has done reasonably well accounting for a broad range of data and is therefore correctly viewed as the current standard model of cosmology (see, e.g. Planck Collaboration XXIII 2014). But recent analyses of the two-point correlation function of the cosmic microwave background (Melia 2014;Copi et al. 2015), as well as the Om(z i , z j ) and Omh 2 (z i , z j ) diagnostics applied to measurements of the Hubble expansion rate H(z) (Shafieloo, Sahni & Starobinsky 2012; Sahni, Shafieloo & Starobinsky 2014), appear to have revealed significant tension between its predictions and recent measurements (see, e.g. Zheng et al. 2016).In this paper, we directly address the problems highlighted by the various analyses carried out with the H(z) data, which apparently do not confirm the anticipated transition from early deceleration E-mail: kyleaf@email.arizona.edu (KL); melia@physics.arizona.eduto more recent acceleration in the cosmic expansion rate (Jimenez & Loeb 2002;Moresco et al. 2016a). With this type of work, one typically compiles a unified sample of H(z) versus redshift measurements based on various approaches, including the determination of differ...

Validation of the Numen Field by the Energy Conditions in the Early Universe

2023

Annalen der Physik

The energy conditions in general relativity are introduced to establish powerful theorems without having to restrict their applicability to specific choices of the stress‐energy tensor. They are famously invoked, e.g., to prove the singularity theorems of Penrose and Hawking, but have also been applied elsewhere, including various tests of certain cosmological theories. These conditions have become somewhat controversial, however, because they appear to be violated by commonly accepted scenarios, such as inflation shortly after the Big Bang and late‐time acceleration of the cosmic expansion. But accommodating these processes by abandoning all of the energy conditions will promote other disquieting possibilities, including the breakdown of causality with traversable wormholes and closed timeloops. This paper advocates for the opposite viewpoint, demonstrating that the ‘numen’ scalar field, derived from the zero active mass condition in general relativity, satisfies all of the energy conditions in the early Universe. This unique feature among scalar fields adds to its success in accounting for the observed properties of the cosmic microwave background better than its inflationary counterpart. Specifically, numen's complete consistency with all of the energy conditions, and inflation's violation of at least one of them, provides additional justification for theoretically favoring the former over the latter.