Dilaton-induced variations in Planck constant and speed of light: An alternative to Dark Energy

Abstract

We reveal a novel aspect of scale-invariant actions that allow matter to couple with a dilaton field: $\,$The dynamics of the dilaton can induce variations in the Planck constant $\hbar$ and speed of light $c$. $\,$Our mechanism for generating variable $\hbar$ and $c$ in $\textit{curved}$ spacetimes via the dilaton offers a viable alternative account for late-time cosmic acceleration, bypassing the need for dark energy.