A Multiverse Outside of the Swampland

TL;DR

This paper proposes a multiverse model arising from landscapes without de Sitter minima, compatible with eternal inflation, and explains fundamental constants without trans-Planckian issues, introducing new mechanisms for universe creation.

Contribution

It demonstrates the feasibility of multiverse scenarios without de Sitter minima and introduces models compatible with the refined de Sitter conjecture and Coleman-De Luccia transitions.

Findings

Multiverse can arise without de Sitter minima during eternal inflation.

Models compatible with the refined de Sitter conjecture are easily constructed.

Transitions between vacua can generate baby Universes during inflation.

Abstract

A Multiverse can arise from landscapes without de Sitter minima. It can be populated during a period of eternal inflation without trans-Planckian field excursions and without flat potentials. This Multiverse can explain the values of the cosmological constant and of the weak scale. In the process of proving these statements we derive a few simple, but counter-intuitive results. We show that it is easy to write models of eternal inflation compatible with the distance and refined de Sitter conjectures. Secondly, tunneling transitions that move fields from a lower-energy vacuum to a higher-energy vacuum and generate baby Universes are possible, and occur during eternal inflation. Finally, we relax the assumption of no de Sitter minima and show that this more standard Multiverse can be populated by Coleman-De Luccia transitions in about 100 $e$-folds of inflation.