Fundamental physics with ESPRESSO: Constraints on Bekenstein and dark energy models from astrophysical and local probes*

Dynamical scalar fields in an effective four-dimensional field theory are naturally expected to couple to the rest of the theory???s degrees of freedom, unless some new symmetry is postulated to suppress these couplings. In particular, a coupling to the electromagnetic sector will lead to spacetime variations of the fine-structure constant, ??. Astrophysical tests of the space-time stability of ?? are therefore a powerful probe of new physics. Here we use ESPRESSO and other contemporary measurements of ??, together with background cosmology data, local laboratory atomic clock and weak equivalence principle measurements, to place stringent constraints on the simplest examples of the two broad classes of varying ?? models: Bekenstein models and quintessence-type dark energy models, both of which are parametric extensions of the canonical ??CDM model. In both cases, previously reported constraints are improved by more than a factor of ten. This improvement is largely due to the very strong local constraints, but astrophysical measurements can help to break degeneracies between cosmology and fundamental physics parameters.

Automated summary

It is expected that dynamical scalar fields in an effective four-dimensional field theory couple to the theory's other degrees of freedom if no new symmetry is introduced to suppress these couplings. This coupling can lead to spacetime variations of the fine-structure constant, which can be tested through astrophysical measurements. In this study, using ESPRESSO and other contemporary measurements, as well as background cosmology data, laboratory atomic clock measurements, and weak equivalence principle measurements, constraints are placed on two classes of varying fine-structure constant models, resulting in significant improvements compared to previous constraints.