Variations of $\alpha$ and $G$ from nonlinear multidimensional gravity

Understand

To explain the recently reported large-scale spatial variations of the fine structure constant $\alpha$, we apply some models of curvature-nonlinear multidimensional gravity.

• Under the reasonable assumption of slow changes of all quantities as compared with the Planck scale, the original theory reduces to a multi-scalar field theory in four dimensions.
• On this basis, we consider different variants of isotropic cosmological models in both Einstein and Jordan conformal frames.
• One of the models turns out to be equally viable in both frames, but in the Jordan frame the model predicts simultaneous variations of $\alpha$ and the gravitational constant $G$, equal in magnitude.