Missing large-angle correlations versus even-odd point-parity imbalance in the cosmic microwave background

Abstract

Context. The existence of a maximum correlation angle (θ max 60 • ) in the two-point angular temperature correlations of cosmic microwave background (CMB) radiation, measured by WMAP and Planck, stands in sharp contrast to the prediction of standard inflationary cosmology, in which the correlations should extend across the full sky (i.e., 180 • ). The introduction of a hard lower cutoff (k min ) in the primordial power spectrum, however, leads naturally to the existence of θ max . Among other cosmological anomalies detected in these data, an apparent dominance of odd-over-even parity multipoles has been seen in the angular power spectrum of the CMB. This feature, however, may simply be due to observational contamination in certain regions of the sky. Aims. In attempting to provide a more detailed assessment of whether this odd-over-even asymmetry is intrinsic to the CMB, we therefore proceed in this paper, first, to examine whether this odd-even parity imbalance also manifests itself in the angular correlation function and, second, to examine in detail the interplay between the presence of θ max and this observed anomaly. Methods. We employed several parity statistics and recalculated the angular correlation function for different values of the cutoff k min in order to optimize the fit to the different Planck 2018 data. Results. We find a phenomenological connection between these features in the data, concluding that both must be considered together in order to optimize the theoretical fit to the Planck 2018 data. Conclusions. This outcome is independent of whether the parity imbalance is intrinsic to the CMB, but if it is, the odd-over-even asymmetry would clearly point to the emergence of new physics.

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

“…[7] The most recent analysis of the Planck data shows that a likely reason for this large-scale anomaly is a hard cutoff, k min = 4.34 ± 0.50∕r cmb , where r cmb is the comoving distance to the surface of last scattering, in the (scalar) fluctuation power spectrum P s (k). [10][11][12] Generic inflation would instead be consistent with an essentially zero k min which, however, is ruled out at over 8𝜎 by these data. Such a spectral cutoff is not easy to accommodate with an inflationary scalar field because k min would signal the first mode crossing the Hubble horizon and freezing during the quasi-de Sitter expansion, [13] establishing the time at which inflation started.…”

“…Both of these anomalies are eliminated by the use of a power spectrum, P s (k), with the aforementioned cutoff, k min . [10,12] The fact that both of the empirically derived anomalies can be accounted for with the same feature in P s (k), i.e., k min , adds weight to the reality of such a cutoff. Actually, it appears that an odd-even parity imbalance is also required to optimize the fit to the Planck-2018 data.…”

“…[ 7 ] The most recent analysis of the Planck data shows that a likely reason for this large‐scale anomaly is a hard cutoff, $$k_{\rm min}=4.34\pm 0.50/r_{\rm cmb}$$, where r cmb is the comoving distance to the surface of last scattering, in the (scalar) fluctuation power spectrum $$P_{\rm s}(k)$$. [ 10–12 ] Generic inflation would instead be consistent with an essentially zero k min which, however, is ruled out at over 8σ by these data.…”

A Population III–Generated Dust Screen at z ∼ 16

“…An in-depth analysis of the latest Planck data focusing on this particular issue (Melia & Lopez-Corredoira 2018;Melia et al 2021;Sanchis-Lozano et al 2022) has shown that the paucity of large-angle correlations is best explained by the presence of a cutoff,…”

“…This outcome is highly relevant to our identification of where the anisotropies in the CMB were produced because it provides an entirely new length scale (i.e., l max ) one may use to estimate z dust . The optimization that completely removes the angular correlation anomaly is given as =  u 4.34 0.50 min , where º u k r min min dust in terms of the comoving radius (r dust ) to the dust screen (Melia & Lopez-Corredoira 2018;Sanchis-Lozano et al 2022). It is easy to see that one may therefore write…”