scholarly journals Strong limit on the spatial and temporal variations of the fine-structure constant

2014 ◽  
Vol 11 (S308) ◽  
pp. 628-630
Author(s):  
T. D. Le
Keyword(s):  
Fine Structure ◽  
Structure Constant ◽  
High Sensitivity ◽  
Temporal Variations ◽  
Mean Value ◽  
Spatial And Temporal Variations ◽  
Fine Structure Constant ◽  
Strong Limit ◽  
History Of ◽  
The Universe

AbstractObserved spectra of quasars provide a powerful tool to test the possible spatial and temporal variations of the fine-structure constant α = e2/ћc over the history of the Universe. It is demonstrated that high sensitivity to the variation of α can be obtained from a comparison of the spectra of quasars and laboratories. We reported a new constraint on the variation of the fine-structure constant based on the analysis of the optical spectra of the fine-structure transitions in [NeIII], [NeV], [OIII], [OI] and [SII] multiplets from 14 Seyfert 1.5 galaxies. The weighted mean value of the α-variation derived from our analysis over the redshift range 0.035 < z < 0.281 Δα/α= (4.50 ± 5.53) \times 10-5. This result presents strong limit improvements on the constraint on Δα/α compared to the published in the literature

scholarly journals TIME VARIATION OF FINE STRUCTURE CONSTANT AND PROTON-ELECTRON MASS RATIO WITH QUINTESSENCE

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2003-2011 ◽  
Author(s):  
SEOKCHEON LEE
Keyword(s):  
Fine Structure ◽  
Scalar Field ◽  
Field Potential ◽  
Structure Constant ◽  
Coupling Constants ◽  
Fine Structure Constant ◽  
Electron Mass ◽  
Mass Ratio ◽  
History Of ◽  
The Universe

Recent astrophysical observations of quasar absorption systems indicate that the fine structure constant α and the proton-electron mass ratio μ may have evolved through the history of the universe. Motivated by these observations, we consider the cosmological evolution of a quintessence-like scalar field ϕ coupled to gauge fields and matter which leads to effective modifications of the coupling constants and particle masses over time. We show that a class of models where the scalar field potential V(ϕ) and the couplings to matter B(ϕ) admit common extremum in ϕ naturally explains constraints on variations of both the fine structure constant and the proton-electron mass ratio.

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 Keck constraints on a varying fine-structure constant: wavelength calibration errors

2009 ◽  
Vol 5 (H15) ◽  
pp. 315-315
Author(s):  
Michael T. Murphy ◽  
John K. Webb ◽  
Victor V. Flambaum
Keyword(s):  
Fine Structure ◽  
Metal Ion ◽  
Random Effect ◽  
Structure Constant ◽  
Mean Value ◽  
Small Samples ◽  
Fine Structure Constant ◽  
Median Error ◽  
Systematic Effects ◽  
Value Changes

AbstractThe Keck telescope's High Resolution Spectrograph (HIRES) has previously provided evidence for a smaller fine-structure constant, α, compared to the current laboratory value, in a sample of 143 quasar absorption systems: Δα/α=(-0.57±0.11)×10−5. The analysis was based on a variety of metal-ion transitions which, if α varies, experience different relative velocity shifts. This result is yet to be robustly contradicted, or confirmed, by measurements on other telescopes and spectrographs; it remains crucial to do so. It is also important to consider new possible instrumental systematic effects which may explain the Keck/HIRES results. Griest et al. (2009) recently identified distortions in the echelle order wavelength scales of HIRES with typical amplitudes ±250 m s−1. Here we investigate the effect such distortions may have had on the Keck/HIRES varying α results. Using a simple model of these intra-order distortions, we demonstrate that they cause a random effect on Δα/α from absorber to absorber because the systems are at different redshifts, placing the relevant absorption lines at different positions in different echelle orders. The typical magnitude of the effect on Δα/α is ~0.4×10−5 for individual absorbers which, compared to the median error on Δα/α in the sample, ~1.9×10−5, is relatively small. Consequently, the weighted mean value changes by less than 0.05×10−5 if the corrections we calculate are applied. Unsurprisingly, with corrections this small, we do not find direct evidence that applying them is actually warranted. Nevertheless, we urge caution, particularly for analyses aiming to achieve high precision Δα/α measurements on individual systems or small samples, that a much more detailed understanding of such intra-order distortions and their dependence on observational parameters is important if they are to be avoided or modelled reliably.

scholarly journals Four direct measurements of the fine-structure constant 13 billion years ago

2020 ◽  
Vol 6 (17) ◽  
pp. eaay9672 ◽  
Author(s):  
Michael R. Wilczynska ◽  
John K. Webb ◽  
Matthew Bainbridge ◽  
John D. Barrow ◽  
Sarah E. I. Bosman ◽  
...  
Keyword(s):  
Fine Structure ◽  
Temporal Change ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Analysis Method ◽  
Weighted Mean ◽  
Near Ir ◽  
Very Large Telescope ◽  
Direct Measurements ◽  
The Universe

Observations of the redshift z = 7.085 quasar J1120+0641 are used to search for variations of the fine structure constant, a, over the redshift range 5:5 to 7:1. Observations at z = 7:1 probe the physics of the universe at only 0.8 billion years old. These are the most distant direct measurements of a to date and the first measurements using a near-IR spectrograph. A new AI analysis method is employed. Four measurements from the x-shooter spectrograph on the Very Large Telescope (VLT) constrain changes in a relative to the terrestrial value (α0). The weighted mean electromagnetic force in this location in the universe deviates from the terrestrial value by Δα/α = (αz − α0)/α0 = (−2:18 ± 7:27) × 10−5, consistent with no temporal change. Combining these measurements with existing data, we find a spatial variation is preferred over a no-variation model at the 3:9σ level.

scholarly journals Variation of the fundamental constants over the cosmological time: veracity of Dirac’s intriguing hypothesis

2016 ◽  
Vol 94 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Cláudio Nassif ◽  
A.C. Amaro de Faria
Keyword(s):  
Fine Structure ◽  
Early Universe ◽  
Early Period ◽  
Planck Scale ◽  
Structure Constant ◽  
Energy Scale ◽  
Fine Structure Constant ◽  
Cosmological Time ◽  
Age Of The Universe ◽  
The Universe

We investigate how the universal constants, including the fine structure constant, have varied since the early universe close to the Planck energy scale (EP ∼ 1019 GeV) and, thus, how they have evolved over the cosmological time related to the temperature of the expanding universe. According to a previous paper (Nassif and Amaro de Faria, Jr. Phys. Rev. D, 86, 027703 (2012). doi:10.1103/PhysRevD.86.027703), we have shown that the speed of light was much higher close to the Planck scale. In the present work, we will go further, first by showing that both the Planck constant and the electron charge were also too large in the early universe. However, we conclude that the fine structure constant (α ≅ 1/137) has remained invariant with the age and temperature of the universe, which is in agreement with laboratory tests and some observational data. Furthermore, we will obtain the divergence of the electron (or proton) mass and also the gravitational constant (G) at the Planck scale. Thus, we will be able to verify the veracity of Dirac’s belief about the existence of “coincidences” between dimensionless ratios of subatomic and cosmological quantities, leading to a variation of G with time, that is, the ratio of the electrostatic to gravitational forces between an electron and a proton (∼1041) is roughly equal to the age of the universe divided by an elementary time constant, so that the strength of gravity, as determined by G, must vary inversely with time in the approximation of lower temperature or for times very far from the early period, to compensate for the time-variation of the Hubble parameter (H ∼ t−1). In short, we will show the validity of Dirac’s hypothesis only for times very far from the early period or T ≪ TP (∼1032 K).

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