Cosmological Constant, Fine Structure Constant and Beyond

TL;DR

This paper explores a model where the cosmological constant varies with the fine structure constant, constrained by quasar absorption data, and interprets it as a combination of dark energy and warm dark matter.

Contribution

It develops a framework for a varying cosmological constant linked to the fine structure constant and constrains it using observational data, offering a novel interpretation involving dark energy and warm dark matter.

Findings

Model parameters are tightly constrained to about 10^{-5}.

Varying cosmological constant model is consistent with warm dark matter constraints.

Framework links varying mbda to lpha and observational data.

Abstract

In the present work, we consider the cosmological constant model $\Lambda\propto\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the hint of varying fine structure constant $\alpha$ was found in 1998. If $\Lambda\propto\alpha^{-6}$ is right, it means that the cosmological constant $\Lambda$ should also be varying. Here, we try to develop a suitable framework to model this varying cosmological constant $\Lambda\propto\alpha^{-6}$, in which we view it from an interacting vacuum energy perspective. Then, we consider the observational constraints on these models by using the 293 $\Delta\alpha/\alpha$ data from the absorption systems in the spectra of distant quasars. We find that the model parameters can be tightly constrained to the very narrow ranges of ${\cal O}(10^{-5})$ typically. On the other hand, we can also view the varying cosmological constant model $\Lambda\propto\alpha^{-6}$ from another perspective, namely it can be equivalent to a model containing "dark energy" and "warm dark matter", but there is no interaction between them. We find that this is also fully consistent with the observational constraints on warm dark matter.