Anisotropic power spectrum and the observed low-lpower in PLANCK CMB data

Abstract

In this work, we study a direction dependent power spectrum in anisotropic Finsler space-time. We use this direction dependent power spectrum to address the low-l power observed in WMAP and PLANCK data. The angular power spectrum of the temperature fluctuations has a lower amplitude in comparison to the ΛCDM model in the multipole range l = 2 − 40. Our theoretical model gives a correction to the isotropic angular power spectrum C T T l due to the breaking of the rotational invariance of the primordial power spectrum. We estimate best-fit model parameters along with the six ΛCDM cosmological parameters using PLANCK likelihood code in CosmoMC software. We see that this modified angular power spectrum fits the CMB temperature data in the multipole range l = 2 − 10 to a good extent but fails for the whole multipole range l = 2 − 40.

Berwald spacetimes and very special relativity

“…In Lorentzian geometry these symmetry demands on spacetime lead to a metric of Friedman-Lemaître-Robertson-Walker (FLRW) type. Finsler geometry has also been considered in the context of cosmological models [49][50][51][52][53][54]. In [11] the most general homogeneous and isotropic Finsler spacetimes were derived.…”

A comprehensive study of modulation effects on CMB polarization

“…Our results imply that the presence of non-diagonal correlations in the polarization field, suggested in the literature [17], cannot be attributed to a modulation in the scalar modes E and B. However our analysis doesn't rule out the possibility that such correlations can arise due to modified power spectra based models [16][17][18][19][20][21][22] that may further arise due to reasons like spacetime non-commutativity [18,43], direction Fig. 2 Plot of the modulating function f in different cases.…”

“…For example, a dipole modulation leads to non diagonal correlations between and ± 1 multipoles. In the literature, the presence of these non-diagonal correlations has been explained on the basis of modification of the primordial power spectrum [16][17][18][19][20][21][22].…”

Finsler space–time can explain both parity asymmetry and power deficit seen in CMB temperature anisotropies

“…However, several largescale anomalies has been reported by WMAP (Hinshaw et al 2013) and PLANCK (Ade et al 2016b) team. For the CMB temperature anisotropies, the anomalies include the power suppression (Efstathiou 2003;Bonga & Gupt 2016;Cai et al 2015;Chang et al 2012;Zhao et al 2015;Chang et al 2018), the parity asymmetry (Hansen et al 2012;Aluri & Jain 2012;Liu et al 2013;Zhao 2014;Land & Magueijo 2005a;Kim & Naselsky 2010b,a;Gruppuso et al 2011), an alignment of quadrupole and octopole (Chang et al 2015;Copi et al 2015a;Land & Magueijo 2005b;Copi et al 2004;Abramo et al 2006), the hemispherical power asymmetry (Chang & Wang 2013;Rath & Jain 2013;Rath et al 2015;Eriksen et al 2007), and the lack of angular power on angular scales larger than 60 • (Spergel et al 2003;Copi et al 2009Copi et al , 2015b.…”