Fundamental Physics with ESPRESSO, Constraining a simple parametrisation for varying $\alpha$

Abstract

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

9 pages, 7 figures, as published in A&A

References in corpus (16)

• Equivalence Principle Violations and Couplings of a Light Dilaton
• Spatial variation in the fine-structure constant -- new results from VLT/UVES
• The status of varying constants: a review of the physics, searches and implications
• Revision of VLT/UVES constraints on a varying fine-structure constant
• Impact of instrumental systematic errors on fine-structure constant measurements with quasar spectra
• Comment on "Limits on the Time Variation of the Electromagnetic Fine-Structure Constant in the Low Energy Limit from Absorption Lines in the Spectra of Distant Quasars"
• High-precision limit on variation in the fine-structure constant from a single quasar absorption system
• The UVES Large Program for testing fundamental physics - III. Constraints on the fine-structure constant from 3 telescopes
• Space test of the Equivalence Principle: first results of the MICROSCOPE mission
• Subaru Telescope limits on cosmological variations in the fine-structure constant
• Fundamental physics with ESPRESSO: Precise limit on variations in the fine-structure constant towards the bright quasar HE 0515$-$4414
• Constraining the Variation of the Fine Structure Constant with Observations of Narrow Quasar Absorption Lines
• Euclid: constraining dark energy coupled to electromagnetism using astrophysical and laboratory data
• Varying fine-structure constant cosmography
• Consistency of local and astrophysical tests of the stability of fundamental constants
• Fundamental physics with ESPRESSO: Constraints on Bekenstein and dark energy models from astrophysical and local probes

Cited by in corpus (6)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Non-parametric reconstruction of the fine structure constant with galaxy clusters
• Coupling quintessence kinetics to electromagnetism
• Relaxing cosmological constraints on current neutrino masses
• Scaling solutions in three-form cosmology
• Future Dark Energy Constraints from Atomic Clocks