Cosmic Evolution in a Cyclic Universe

TL;DR

This paper proposes a cyclic universe model based on ekpyrotic scenario and M-theory, where the universe undergoes endless cycles of expansion and contraction, with cosmic acceleration playing a key role in resetting initial conditions.

Contribution

It introduces a detailed cyclic universe model incorporating cosmic acceleration to reset initial conditions and ensure an eternal, repeating cosmic cycle based on M-theory concepts.

Findings

The universe undergoes endless cycles of big bang and big crunch.

Cosmic acceleration helps remove debris and reset initial conditions.

The model acts as an attractor, ensuring cyclicity persists indefinitely.

Abstract

Based on concepts drawn from the ekpyrotic scenario and M-theory, we elaborate our recent proposal of a cyclic model of the Universe. In this model, the Universe undergoes an endless sequence of cosmic epochs which begin with the Universe expanding from a `big bang' and end with the Universe contracting to a `big crunch.' Matching from `big crunch' to `big bang' is performed according to the prescription recently proposed with Khoury, Ovrut and Seiberg. The expansion part of the cycle includes a period of radiation and matter domination followed by an extended period of cosmic acceleration at low energies. The cosmic acceleration is crucial in establishing the flat and vacuous initial conditions required for ekpyrosis and for removing the entropy, black holes, and other debris produced in the preceding cycle. By restoring the Universe to the same vacuum state before each big crunch, the acceleration insures that the cycle can repeat and that the cyclic solution is an attractor.