Catalytic Creation of Baby Bubble Universe with Small Positive Cosmological Constant

TL;DR

This paper explores how black holes and string clouds can catalyze the formation of a baby universe with a tiny positive cosmological constant, using a five-dimensional anti-de Sitter spacetime model.

Contribution

It introduces a novel mechanism for creating a bubble universe with a small positive cosmological constant via catalysis by black holes and string clouds.

Findings

Small cosmological constant bubble is favored by catalysis.

Black hole and string cloud parameters can reproduce current matter and radiation densities.

The study applies to a recently proposed four-dimensional bubble universe in five-dimensional AdS space.

Abstract

We investigate the decay of metastable de Sitter, Minkowski and anti-de Sitter vacua catalyzed by a black hole and a cloud of strings. We apply the method to the creation of the four dimensional bubble universe in the five dimensional anti-de Sitter spacetime recently proposed by Banerjee, Danielsson, Dibitetto, Giri and Schillo. We study the bounce action for the creation and find that the bubble with very small cosmological constant, of order $\Lambda^{(4)}/M^2_4 \sim 10^{-120}$, is favored by the catalysis by assuming appropriate mass scales of the black hole and the cloud of strings to reproduce the present energy densities of matter and radiation in the bubble universe.