Gravitational lens time-delay as a probe of a possible time variation of the fine-structure constant

Abstract

A new method based on large scale structure observations is proposed to probe a possible temporal variation of the fine-structure constant (α). Our analyses are based on time-delay of Strong Gravitational Lensing and Type Ia Supernovae observations. By considering the runaway dilaton scenario, where the cosmological temporal evolution of the fine-structure constant is given by Δαα≈-γln(1+z), we obtain limits on the physical properties parameter of the model (γ) at the level 10 - 2 (1 σ). Although our limits are less restrictive than those obtained by quasar spectroscopy, the approach presented here provides new bounds on the possibility of Δαα≠0 at a different range of redshifts.