Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background
Affiliation
Univ Arizona, Dept Phys, Appl Math ProgramUniv Arizona, Dept Astron
Issue Date
2018-03-09Keywords
cosmic background radiationcosmology: observations
cosmology: theory
early Universe
inflation
large-scale structure of Universe
Metadata
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EDP SCIENCES S ACitation
Melia, F., & Lopez-Corredoira, M. (2018). Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background. Astronomy & Astrophysics, 610, A87.Journal
ASTRONOMY & ASTROPHYSICSRights
© ESO, 2018.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
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.Note
Open access journalISSN
0004-63611432-0746
Version
Final accepted manuscriptAdditional Links
https://www.aanda.org/10.1051/0004-6361/201732181https://arxiv.org/pdf/1712.07847.pdf
ae974a485f413a2113503eed53cd6c53
10.1051/0004-6361/201732181