Universes out of almost empty space

TL;DR

This paper demonstrates that baby universes can form from nearly empty space with minimal energy, challenging previous assumptions and exploring their properties and implications.

Contribution

It introduces a new classical solution showing baby universes can emerge from almost flat space with negligible energy, expanding understanding of universe formation.

Findings

Baby universes can form from almost empty space with arbitrarily small energy.

The solution involves string-like matter configurations.

Implications for universe creation and cosmology are discussed.

Abstract

Baby universes (inflationary or non--inflationary) are regions of spacetime that disconnect from the original ambient spacetime, which we take to be asymptotically flat spacetime. A particular kind of baby universe solution, involving string--like matter, is studied to show that it can be formed by ``investing'' an arbitrarily small amount of energy, i.e. it can appear from an almost flat space at the classical level. Since this possibility has not yet been clearly recognized in the literature, we then discuss in detail its properties, relevance and possible generalizations.