Coupling quintessence kinetics to electromagnetism

Understand

We propose a general model where quintessence couples to electromagnetism via its kinetic term.

• This novelty generalizes the linear dependence of the gauge kinetic function on $\phi$, commonly adopted in the literature.
• The interaction naturally induces a time variation of the fine-structure constant that can be formulated within a disformally coupled framework, akin to a Gordon metric.
• Through a suitable parametrization of the scalar field and the coupling function, we test the model against observations sensitive to the variation of $\alpha$.