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

TL;DR

This paper introduces a novel method using gravitational lens time-delay and supernovae data to constrain potential variations in the fine-structure constant over cosmic time, offering bounds at different redshifts.

Contribution

It presents a new approach combining large-scale structure observations with lensing and supernova data to limit the variation of the fine-structure constant.

Findings

Limits on the parameter γ at the level of 10^{-2} (1σ)

Constraints are less restrictive than quasar spectroscopy but cover different redshift ranges

Provides bounds on Δα/α at various cosmic epochs

Abstract

A new method based on large-scale structure observations is proposed to probe a possible time 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 a class of runaway dilaton models, where the cosmological 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 $\frac{\Delta \alpha}{\alpha} \neq 0$ at a different range of redshifts.