Cosmological Avatars of the Landscape II: CMB and LSS Signatures

TL;DR

This paper explores how modifications to the Friedmann equation from landscape models imprint unique signatures on the CMB and LSS, potentially explaining observed data and revealing noninflationary contributions.

Contribution

It demonstrates how long wavelength mode effects alter cosmological spectra, providing distinctive observational signatures that differentiate this model from others.

Findings

Suppression of $\sigma_8$ and CMB $TT$ spectrum at large angles.

Imprinted features on matter power spectrum indicating primordial voids.

Correlation signatures between cosmic shear and temperature anisotropies suggest noninflationary LSS contributions.

Abstract

This is the second paper in the series that confronts predictions of a model of the landscape with cosmological observations. We show here how the modifications of the Friedmann equation due to the decohering effects of long wavelength modes on the wavefunction of the Universe defined on the landscape leave unique signatures on the CMB spectra and large scale structure (LSS). We show that the effect of the string corrections is to suppress $\sigma_8$ and the CMB $TT$ spectrum at large angles, thereby bringing WMAP and SDSS data for $\sigma_8$ into agreement. We find interesting features imprinted on the matter power spectrum $P(k)$: power is suppressed at large scales indicating the possibility of primordial voids competing with the ISW effect. Furthermore, power is enhanced at structure and substructure scales, $k\simeq 10^{-2-0} h~{\rm Mpc}^{-1}$. Our smoking gun for discriminating this proposal from others with similar CMB and LSS predictions come from correlations between cosmic shear and temperature anisotropies, which here indicate a noninflationary channel of contribution to LSS, with unique ringing features of nonlocal entanglement displayed at structure and substructure scales.