Fundamental cosmology in the E-ELT era: the status and future role of tests of fundamental coupling stability

Martins, C. J. A. P.

doi:10.1007/s10714-014-1843-7

Cited by 32 publications

(48 citation statements)

References 58 publications

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“…In addition to the intrinsic importance of these more precise measurements, which our present work highlights, they will also lead to improved constraints on dynamical dark energy and on Weak Equivalence Principle violations. A roadmap for these tests can be found in [2].…”

Section: Discussionmentioning

confidence: 99%

Stability of fundamental couplings: A global analysis

Martins

Pinho

2017

Phys. Rev. D

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Astrophysical tests of the stability of fundamental couplings are becoming an increasingly important probe of new physics. Motivated by the recent availability of new and stronger constraints we update previous works testing the consistency of measurements of the fine-structure constant α and the proton-to-electron mass ratio µ = mp/me (mostly obtained in the optical/ultraviolet) with combined measurements of α, µ and the proton gyromagnetic ratio gp (mostly in the radio band). We carry out a global analysis of all available data, including the 293 archival measurements of Webb et al. and 66 more recent dedicated measurements, and constraining both time and spatial variations. While nominally the full datasets show a slight statistical preference for variations of α and µ (at up to two standard deviations), we also find several inconsistencies between different sub-sets, likely due to hidden systematics and implying that these statistical preferences need to be taken with caution. The statistical evidence for a spatial dipole in the values of α is found at the 2.3 sigma level. Forthcoming studies with facilities such as ALMA and ESPRESSO should clarify these issues.

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Section: Discussionmentioning

confidence: 99%

Stability of fundamental couplings: A global analysis

Martins

Pinho

2017

Phys. Rev. D

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“…Whenever dynamical scalar fields are present, one naturally expects them to couple to the rest of the model, unless a yetunknown symmetry suppresses these couplings [3]. In particular, a coupling to the electromagnetic sector will lead to spacetime variations of the fine-structure constant, which unavoidably imply a violation of the Einstein Equivalence Principle-see [4,5] for recent reviews.…”

Section: Introductionmentioning

confidence: 99%

“…A significant effort is being put into independently confirming this result, including a dedicated Large Program with the Very Large Telescope's UVES spectrograph [7][8][9]. Improving these tests * Ana.Leite@astro.up.pt † Carlos.Martins@astro.up.pt is also a flagship science case for forthcoming facilities such as ESPRESSO [10] and ELT-HIRES [11]; a roadmap for these future tests is discussed in [5]. Meanwhile, an extensive range of theoretical models including varying couplings have been studied (see [4] for an overview).…”

Section: Introductionmentioning

confidence: 99%

Current and future constraints on Bekenstein-type models for varying couplings

Leite

Martins

2016

Phys. Rev. D

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Astrophysical tests of the stability of dimensionless fundamental couplings, such as the finestructure constant α and the proton-to-electron mass ratio µ, are an optimal probe of new physics. There is a growing interest in these tests, following indications of possible spacetime variations at the few parts per million level. Here we make use of the latest astrophysical measurements, combined with background cosmological observations, to obtain improved constraints on Bekensteintype models for the evolution of both couplings. These are arguably the simplest models allowing for α and µ variations, and are characterized by a single free dimensionless parameter, ζ, describing the coupling of the underlying dynamical degree of freedom to the electromagnetic sector. In the former case we find that this parameter is constrained to be |ζα| < 4.8 × 10 −6 (improving previous constraints by a factor of 6), while in the latter (which we quantitatively compare to astrophysical measurements for the first time) we find ζµ = (2.7 ± 3.1) × 10 −7 ; both of these are at the 99.7% confidence level. For ζα this constraint is about 20 times stronger than the one obtained from local Weak Equivalence Principle tests, while for ζµ it is about 2 orders of magnitude weaker. We also discuss the improvements on these constraints to be expected from the forthcoming ESPRESSO and ELT-HIRES spectrographs, conservatively finding a factor around 5 for the former and around 50 for the latter.

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“…In view of the paradigm-shifting ramifications of these findings, mined from data taken for other purposes, and concerns about the wavelength calibration of the HIRES and UVES spectrographs (which seem to have been borne out by the recent identification of long range distortions [5]), the UVES LARGE Program of dedicated observations has been initiated to check the evidence for non-zero changes in α [6]. However, the difficulties of the spectroscopic measurements involved demand a new generation of ultra-stable high resolution spectrographs [7], two of which (PEPSI and ESPRESSO) it is envisaged will begin operating within a year or so.…”

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confidence: 99%