Cosmological constant is probably adjustable in brane worlds

TL;DR

This paper investigates the probability of the universe evolving into a near-flat state within brane world models that feature self-tuning properties of the cosmological constant, suggesting it is highly probable under certain parameters.

Contribution

It demonstrates that in specific brane world models, the transition amplitude favors nearly flat universes, indicating the cosmological constant may be adjustable.

Findings

Transition amplitude is exponentially dominated by small curvature.

Probability favors universes with very small cosmological constant.

Certain parameter ranges lead to a high likelihood of near-flat universes.

Abstract

In the brane world scenario, possessing the self-tuning property of the cosmological constant, we study the probability amplitude for an initial state of the Universe to transform to final states with some curvatures. In the Kim, Kyae and Lee model, there exists a finite range of parameters such that the transition amplitude to a near flat universe is exponentially dominated by the smallness of curvature, > e^{positive number}/{Lambda-bar}^2}, i.e. is dominated by an almost flat universe of |Lambda-bar|<epsilon.