Varying Fine-Structure Constant and the Cosmological Constant Problem

TL;DR

This paper explores the potential link between variations in the fine-structure constant and the cosmological constant problem, proposing a scalar-tensor theory involving a dilaton field to explain recent observational data.

Contribution

It introduces a scalar-tensor framework with a dilaton field to unify explanations for the variability of alpha and the accelerating universe.

Findings

Constraints from Oklo phenomenon limit alpha variability

QSO measurements suggest non-uniform alpha variation over time

Scalar-tensor theory can account for both phenomena with a common scalar field behavior

Abstract

We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time-variability of the fine- structure constant $\alpha$. Comparing this with the recent result from the measurement of distant QSO's appears to indicate a non-uniform time-dependence, which we argue to be related to another recent finding of the accelerating universe. This view is implemented in terms of the scalar-tensor theory, applied specifically to the small but nonzero cosmological constant. Our detailed calculation shows that these two phenomena can be understood in terms of a common origin, a particular behavior of the scalar field, dilaton. We also sketch how this theoretical approach makes it appropriate to revisit non- Newtonian gravity featuring small violation of Weak Equivalence Principle at medium distances.