Bibcode
Melia, F.; López-Corredoira, M.
Bibliographical reference
Astronomy and Astrophysics, Volume 610, id.A87, 5 pp.
Advertised on:
3
2018
Journal
Citations
29
Refereed citations
26
Description
Aim. The lack of large-angle correlations in the fluctuations of the
cosmic microwave background (CMB) conflicts with predictions of
slow-roll inflation. But while probabilities (≲0.24%) for the
missing correlations disfavour the conventional picture at
≳3σ, factors not associated with the model itself may be
contributing to the tension. Here we aim to show that the absence of
large-angle correlations is best explained with the introduction of a
non-zero minimum wave number kmin for the fluctuation power
spectrum P(k). Methods: We assumed that quantum fluctuations were
generated in the early Universe with a well-defined power spectrum P(k),
although with a cut-off kmin ≠ 0. We then re-calculated
the angular correlation function of the CMB and compared it with Planck
observations. Results: The Planck 2013 data rule out a zero
kmin at a confidence level exceeding 8σ. Whereas purely
slow-roll inflation would have stretched all fluctuations beyond the
horizon, producing a P(k) with kmin = 0 - and therefore
strong correlations at all angles - a kmin ≠ 0 would
signal the presence of a maximum wavelength at the time
(tdec) of decoupling. This argues against the basic
inflationary paradigm, and perhaps even suggests non-inflationary
alternatives, for the origin and growth of perturbations in the early
Universe. In at least one competing cosmology, the Rh = ct
universe, the inferred kmin corresponds to the gravitational
radius at tdec.
Related projects
![We can’t see dark matter, but its gravity sculpts what we do see from our vantage point inside the Milky Way galaxy. This supercomputer simulation, which looks at our cosmic neighborhood from the outside, is a realistic, data-driven reconstruction of the web of dark matter that guided galaxies to their present positions. Where huge dark tendrils cross, bright galaxies cluster; the Virgo cluster alone includes thousands. Simulation and Reconstruction: Steffen Hess and Francisco-Shu Kitaura, Leibniz Institute for Astrophysics Potsdam. Visualization: Tom Abel and Ralf Kaehler. Credits: National Geographic The Invisible Scaffolding of Space](/sites/default/files/styles/crop_square_2_2_to_320px/public/images/project/Imagen%20Kitaura.jpg?h=b3e11503&itok=8oVjxQtK)
Cosmology with Large Scale Structure Probes
The Cosmic Microwave Background (CMB) contains the statistical information about the early seeds of the structure formation in our Universe. Its natural counterpart in the local universe is the distribution of galaxies that arises as a result of gravitational growth of those primordial and small density fluctuations. The characterization of the
FRANCISCO SHU
KITAURA JOYANES