Coupling quintessence kinetics to electromagnetism

Abstract We propose a general model where quintessence couples to electromagnetism via its kinetic term. This novelty generalizes the linear dependence of gauge function on ϕ , commonly adopted in literature. The interaction naturally induces time variation fine-structure constant that can be formulated within disformally coupled framework, akin Gordon metric. Through suitable parametrization scalar field and coupling function, we test against observations sensitive α . undertake Bayesian analysis infer free parameters with data from Earth based, astrophysical early Universe experiments. find evolution is specific each cosmological era slows down at late times when dark energy accelerates Universe. While most stringent bound obtained atomic clocks measurements, quasars provide constraint consistent weak equivalence principle tests. promising further tested upcoming more precise such as those ESPRESSO spectrograph.