Fundamental physics with ESPRESSO: Constraining a simple parametrisation for varying <i>?</i>

The spectrograph ESPRESSO recently obtained a limit on the variation of fine-structure constant, $\alpha$, through measurements along line sight bright quasar with precision $1.36$ ppm at $1\sigma$ level. This imposes new constraints cosmological models varying $\alpha$. We assume such model where electromagnetic sector is coupled to scalar field dark energy responsible for current acceleration Universe. parametrise $\alpha$ two extra parameters, one defining evolution quintessence component and other fixing coupling field. objective this work constrain these parameters both astrophysical local probes. also carried out comparative analysis how each data probe may our parametrisation. performed Bayesian by comparing predictions observations. datasets are composed spectra measurements, including latest point, as well Planck observations cosmic microwave background. combined results from atomic clocks MICROSCOPE experiment. placed parameter consistent null field, therefore compatible $\Lambda$CDM cosmology. dominated E\"otv\"os bound. More precise will be extremely important study it probes an interval redshift not accessible types However, particular model, available favour resulting mostly strong limits.