Populating the landscape in an inhomogeneous universe

TL;DR

This paper uses 3+1D Numerical Relativity simulations to study how an initially inhomogeneous universe evolves, revealing mechanisms for the formation of de Sitter and Anti-de Sitter vacua, including bubble formation and black hole collapse.

Contribution

It introduces a novel numerical relativity approach to simulate scalar field evolution in an inhomogeneous universe, exploring landscape population dynamics.

Findings

Different vacua regions form with clear boundaries

Expanding de Sitter bubbles coexist with collapsing AdS regions

Black holes can form from collapsing AdS bubbles

Abstract

The primordial Universe might be highly inhomogeneous. We perform the 3+1D Numerical Relativity simulation for the evolution of scalar field in an initial inhomogeneous expanding Universe, and investigate how it populates the landscape with both de Sitter (dS) and AdS vacua. The simulation results show that eventually either the field in different region separates into different vacua, so that the expanding dS or AdS bubbles (the bubble wall is expanding but the spacetime inside AdS bubbles is contracting) come into being with clear bounderies, or overall region is dS expanding with a few smaller AdS bubbles (which collapsed into black holes) or inhomogeneously collapsing.