scholarly journals Measuring the fine structure constant on a white dwarf surface; a detailed analysis of Fe V absorption in G191-B2B

2020 ◽  
Author(s):  
J Hu ◽  
J K Webb ◽  
T R Ayres ◽  
M B Bainbridge ◽  
J D Barrow ◽  
...  
Keyword(s):  
Fine Structure ◽  
White Dwarf ◽  
Hubble Space Telescope ◽  
Zeeman Effect ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Gravitational Fields ◽  
Systematic Uncertainties ◽  
Isotopic Abundances ◽  
Comprehensive Search

Abstract The gravitational potential φ = GM/Rc2 at the surface of the white dwarf G191-B2B is 10,000 times stronger than that at the Earth’s surface. Numerous photospheric absorption features are detected, making this a suitable environment to test theories in which the fundamental constants depend on gravity. We have measured the fine structure constant, α, at the white dwarf surface, used a newly calibrated Hubble Space Telescope STIS spectrum of G191-B2B, two new independent sets of laboratory Fe V wavelengths, and new atomic calculations of the sensitivity parameters that quantify Fe V wavelength dependency on α. The two results obtained are: Δα/α0 = (6.36 ± 0.35stat ± 1.84sys) × 10−5 and Δα/α0 = (4.21 ± 0.48stat ± 2.25sys) × 10−5. The measurements hint that the fine structure constant increases slightly in the presence of strong gravitational fields. A comprehensive search for systematic errors is summarised, including possible effects from line misidentifications, line blending, stratification of the white dwarf atmosphere, the quadratic Zeeman effect and electric field effects, photospheric velocity flows, long-range wavelength distortions in the HST spectrum, and variations in the relative Fe isotopic abundances. None fully account for the observed deviation but the systematic uncertainties are heavily dominated by laboratory wavelength measurement precision.

scholarly journals Constraining the magnetic field on white dwarf surfaces; Zeeman effects and fine structure constant variation

2019 ◽  
Vol 485 (4) ◽  
pp. 5050-5058 ◽  
Author(s):  
J Hu ◽  
J K Webb ◽  
T R Ayres ◽  
M B Bainbridge ◽  
J D Barrow ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Fine Structure ◽  
White Dwarf ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Line Profiles ◽  
Space Telescope ◽  
Gravitational Fields ◽  
Upper Limit ◽  
The Magnetic Field

ABSTRACT White dwarf (WD) atmospheres are subjected to gravitational potentials around 105 times larger than occur on Earth. They provide a unique environment in which to search for any possible variation in fundamental physics in the presence of strong gravitational fields. However, a sufficiently strong magnetic field will alter absorption line profiles and introduce additional uncertainties in measurements of the fine structure constant. Estimating the magnetic field strength is thus essential in this context. Here, we model the absorption profiles of a large number of atomic transitions in the WD photosphere, including first-order Zeeman effects in the line profiles, varying the magnetic field as a free parameter. We apply the method to a high signal-to-noise, high-resolution, far-ultraviolet Hubble Space Telescope/Space Telescope Imaging Spectrograph spectrum of the WD G191−B2B. The method yields a sensitive upper limit on its magnetic field of B < 2300 G at the 3σ level. Using this upper limit, we find that the potential impact of quadratic Zeeman shifts on measurements of the fine structure constant in G191−B2B is 4 orders of magnitude below laboratory wavelength uncertainties.

scholarly journals Limits on the Dependence of the Fine-Structure Constant on Gravitational Potential from White-Dwarf Spectra

2013 ◽  
Vol 111 (1) ◽  
Author(s):  
J. C. Berengut ◽  
V. V. Flambaum ◽  
A. Ong ◽  
J. K. Webb ◽  
John D. Barrow ◽  
...  
Keyword(s):  
Fine Structure ◽  
Gravitational Potential ◽  
White Dwarf ◽  
Structure Constant ◽  
Fine Structure Constant

scholarly journals The Theoretical Value of the Hubble Constant Ho and Unification of the Fundamental Forces of Nature

2021 ◽  
Vol 3 (4) ◽  
pp. 17-24
Author(s):  
Paul Cadelina Rivera
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Hubble Constant ◽  
High Energy ◽  
Theoretical Explanation ◽  
Fine Structure Constant ◽  
Fundamental Relation ◽  
Gravitational Fields ◽  
Cosmological Observations ◽  
Fundamental Forces

The Hubble constant Ho represents the speed of expansion of the universe and various cosmological observations and modeling methods were utilized by astronomers for a century to pin down its exact value. Determining Ho from cosmological observations is a long and tedious process requiring highly accurate datasets. To circumvent this need, a simple theoretical approach is introduced in this study which uses the concept of gravitational weakening and seismic-induced recession. As tremors occur among celestial objects, their gravitational fields would also change. This resulted in a fundamental relation of Ho and the computed rate of recession that gives a theoretical value for Ho=69.921 Km/s/Mpc. Using the newly discovered seismic-induced gravitational weakening and time dilation, it is possible that various astrophysical methods using different measurement methods would converge to this theoretical Ho value when cosmological distances and time delay measurements are corrected with the simple formulas we derived. The new model assumes that, as quakes occur in celestial objects, luminosity-induced acceleration and high-energy collision of protons and electrons may produce a massive number of neutrinos, quarks and other subatomic particles. Furthermore, the fine structure constant was found to be inversely proportional to Ho-squared and that the fine-structure constant obtained in this study gives a new physical interpretation of α. New relations for the speed of light, orbital velocity, gravitational force and the Hubble constant were further derived from the new recession constant using approximate relations for the Newtonian and electric force constant. This resulted in a modified gravitational law that is both repulsive and attractive and a theoretical explanation of the phenomenon of light-induced gravitation analogous to the electromagnetic force where photon is the force-carrier. Finally, the fundamental forces of gravitation, electromagnetism and strong nuclear force are now unified.

scholarly journals Updated Constraints on the Variations of the Fine-Structure Constant from an Analysis of White-Dwarf Spectra

Symmetry ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 936
Author(s):  
Le
Keyword(s):  
Fine Structure ◽  
Temporal Variation ◽  
White Dwarf ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Spatial And Temporal Variation ◽  
Dwarf Star

I used observed spectra from the white-dwarf star G191-B2B to constrain the spatial and temporal variation of the fine-structure constant,[...]

scholarly journals Probing the Gravitational Dependence of the Fine-Structure Constant from Observations of White Dwarf Stars

Universe ◽  
2017 ◽  
Vol 3 (2) ◽  
pp. 32 ◽  
Author(s):  
Matthew Bainbridge ◽  
Martin Barstow ◽  
Nicole Reindl ◽  
W.-Ü Tchang-Brillet ◽  
Thomas Ayres ◽  
...  
Keyword(s):  
Fine Structure ◽  
White Dwarf ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Dwarf Stars ◽  
White Dwarf Stars

scholarly journals New Limit on Space-Time Variations in the Proton-to-Electron Mass Ratio from Analysis of Quasar J110325-264515 Spectra

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 344
Author(s):  
T. D. Le
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
Space Time ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Mass Ratio ◽  
Quasar Spectra ◽  
Time Variations ◽  
Using Data ◽  
The Universe

Astrophysical tests of current values for dimensionless constants known on Earth, such as the fine-structure constant, α , and proton-to-electron mass ratio, μ = m p / m e , are communicated using data from high-resolution quasar spectra in different regions or epochs of the universe. The symmetry wavelengths of [Fe II] lines from redshifted quasar spectra of J110325-264515 and their corresponding values in the laboratory were combined to find a new limit on space-time variations in the proton-to-electron mass ratio, ∆ μ / μ = ( 0.096 ± 0.182 ) × 10 − 7 . The results show how the indicated astrophysical observations can further improve the accuracy and space-time variations of physics constants.

scholarly journals Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector

2019 ◽  
Vol 218 ◽  
pp. 02012
Author(s):  
Graziano Venanzoni
Keyword(s):  
Fine Structure ◽  
Energy Region ◽  
Direct Evidence ◽  
Branching Ratio ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Recent Measurement ◽  
Single Measurement ◽  
Lepton Universality ◽  
Hadronic Contribution

I will report on the recent measurement of the fine structure constant below 1 GeV with the KLOE detector. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribution to the running of α(s), which is the strongest direct evidence both in time-and space-like regions achieved in a single measurement. From a fit of the real part of Δα(s) and assuming the lepton universality the branching ratio BR(ω → µ+µ−) = (6.6 ± 1.4stat ± 1.7syst) · 10−5 has been determined

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