A Cyclic Model of the Universe

TL;DR

A cosmological model in which the universe undergoes an endless sequence of cosmic epochs that begin with a "bang" and end in a “crunch" is proposed, which produces the homogeneity, flatness, and energy needed to begin the next cycle.

Abstract

We propose a cosmological model in which the universe undergoes an endless sequence of cosmic epochs each beginning with a `bang' and ending in a `crunch.' The temperature and density are finite at each transition from crunch to bang. Instead of having an inflationary epoch, each cycle includes a period of slow accelerated expansion (as recently observed) followed by slow contraction. The combination produces the homogeneity, flatness, density fluctuations and energy needed to begin the next cycle.

Figures (1)

• Figure 1: Schematic plot of the potential $V(\phi)$ versus field $\phi$. In M theory, $\phi$ determines the distance between branes, and $\phi \rightarrow -\infty$ as the branes collide. We define $\phi$ to be zero where $V(\phi)$ crosses zero and, therefore, $\phi$ is positive when the branes are at their maximal separation. Far to the right, the potential asymptotes to $\rho_Q^0$, the current value of the quintessence (dark energy) density. The solid circles represent the dark energy dominated stage; the grey represent the contracting phase during which density fluctuations are generated; the open circles represent the phase when the scalar kinetic energy dominates; and the broken circle represents the stage when the universe is radiation dominated. Further details of the sequence of stages are described in the article.