Predicting the CMB power spectrum for binary polyhedral spaces

TL;DR

This paper demonstrates that finite, multi-connected universe models based on binary polyhedral spaces can explain the low quadrupole and octopole anomalies in the CMB power spectrum, using a novel computational technique.

Contribution

It introduces a new method to compute the CMB spectrum and variance for binary polyhedral spaces using group-averaging operators and Lie group symmetries.

Findings

Spectrum and variance computed up to k=102.

Spectrum can be derived from the radial function alone.

Uncertainty in total energy density estimates can be reduced significantly.

Abstract

The COBE and the first-year WMAP data both find the CMB quadrupole and octopole to be anomalously low. Here it is shown, that a finite, multi-connected universe may explain this anomaly, supporting earlier analyses [5][18]. A novel technique, pioneered by [16] is used to compute the spectrum and its variance up to k=102. Based on the properties of the Lie group of rotations of S^3 it is shown that the spectrum and its variance may be computed solely from the matrix elements of the group-averaging operator, for each of the manifolds S^3/I^*, S^3/O^* and S^3/T^*. Further, it is proved that the spectrum of the CMB may be calculated solely from the radial function, due to the symmetry properties of the Lie-algebra, which is rigorously proven. It is shown, that if the topology of the universe is S^3/I^* the uncertainty on the estimates for the total energy density of the universe may be reduced by an order of magnitude. Finally, the paper highlights how the unavailability of an explicit probability function for the observations, given the model, is a challenge for Monte-Carlo simulations of the binary polyhedral spaces which has to be addressed in future work.