Diversity in the Phoenix Universe

TL;DR

This paper explores how the cyclic universe model can produce diverse regions with varying density fluctuations and non-gaussian features, aligning with observational data and enriching the universe's global structure.

Contribution

It demonstrates that the phoenix universe framework naturally leads to spatially varied density and non-gaussianity, expanding the understanding of cosmic diversity.

Findings

Regions with fluctuation amplitude Q ~ 10^{-4.5}

Non-gaussianity parameters f_{NL} ~ ±10, g_{NL} ~ -10^3

Agreement with current observational constraints

Abstract

It has recently been argued by Copeland et al. that in eleven dimensions two orbifold planes can collide and bounce in a regular way, even when the bulk metric is perturbed away from Milne spacetime to a Kasner solution. In this paper, we point out that as a consequence the global "phoenix" structure of the cyclic universe is significantly enriched. Spatially separated regions, with different density fluctuation amplitudes as well as different non-gaussian characteristics, are all physically realized. Those regions containing by far the most structure are specified by a fluctuation amplitude of Q ~ 10^{-4.5} and local non-gaussianity parameters f_{NL} ~ O(+/- 10) and g_{NL} ~ O(-10^3), in agreement with current observations.