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

A new method based on large scale structure observations is proposed to probe a possible temporal variation of the fine-structure constant ( $$\alpha $$ ). 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 $$\frac{\Delta \alpha }{\alpha } \approx -\gamma \ln {(1+z)}$$ , we obtain limits on the physical properties parameter of the model ( $$\gamma $$ ) at the level $$10^{-2}$$ ( $$1\sigma $$ ). Although our limits are less restrictive than those obtained by quasar spectroscopy, the approach presented here provides new bounds on the possibility of $$\frac{\Delta \alpha }{\alpha } \ne 0$$ at a different range of redshifts.