The Cosmological Constant in the Quantum Multiverse

TL;DR

This paper introduces a quantum-mechanical framework for the multiverse that predicts the distribution of the cosmological constant, aligning with observed values and favoring a positive cosmological constant.

Contribution

It develops a unified quantum framework for multiverse predictions and calculates the probability distribution of the cosmological constant, addressing previous measure issues.

Findings

Observed cosmological constant is consistent with the predicted distribution.

The framework prefers a positive cosmological constant over a negative one.

Results are robust against variations in galaxy formation and life evolution models.

Abstract

Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and outcomes of particular experiments, according to a single probability formula. This provides complete unification of the eternally inflating multiverse and many worlds in quantum mechanics. In this paper we elucidate how cosmological parameters can be calculated in this framework, and study the probability distribution for the value of the cosmological constant. We consider both positive and negative values, and find that the observed value is consistent with the calculated distribution at an order of magnitude level. In particular, in contrast to the case of earlier measure proposals, our framework prefers a positive cosmological constant over a negative one. These results depend only moderately on how we model galaxy formation and life evolution therein.