Eternal inflation and the initial singularity

TL;DR

The paper demonstrates that any physically reasonable eternally inflating spacetime inevitably begins with an initial singularity, highlighting a fundamental limitation of eternal inflation models.

Contribution

It proves that eternal inflation models cannot be free of initial singularities under reasonable physical assumptions.

Findings

Eternal inflation spacetimes must have an initial singularity.

The initial singularity is unavoidable in physically reasonable models.

Supports the idea that inflationary models have a beginning.

Abstract

It is shown that a physically reasonable spacetime that is eternally inflating to the future must possess an initial singularity.