ORCID Profile
0000-0002-4718-1051
Current Organisation
E O Lawrence Berkeley National Laboratory
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Publisher: Oxford University Press (OUP)
Date: 14-01-2015
Publisher: Oxford University Press (OUP)
Date: 14-02-2017
DOI: 10.1093/MNRAS/STX381
Publisher: AIP Publishing
Date: 28-05-2022
DOI: 10.1063/5.0088264
Abstract: We present a comparative analysis of urban magnetic fields between two American cities: Berkeley (California) and Brooklyn Borough of New York City (New York). Our analysis uses data taken over a four-week period during which magnetic field data were continuously recorded using a fluxgate magnetometer with 70 pT/Hz noise. We identified significant differences in the magnetic signatures. In particular, we noticed that Berkeley reaches a near-zero magnetic field activity at night, whereas magnetic activity in Brooklyn continues during nighttime. We also present auxiliary measurements acquired using magnetoresistive vector magnetometers (VMRs), with the noise of 300 pT/Hz, and demonstrate how cross correlation, and frequency-domain analysis, combined with data filtering can be used to extract urban-magnetometry signals and study local anthropogenic activities. Finally, we discuss the potential of using magnetometer networks to characterize the global magnetic field of cities and give directions for future development.
Publisher: Elsevier BV
Date: 12-2018
Publisher: Oxford University Press (OUP)
Date: 22-03-2017
DOI: 10.1093/MNRAS/STX681
Publisher: Oxford University Press (OUP)
Date: 23-10-2020
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.
Publisher: EDP Sciences
Date: 06-2012
Publisher: IOP Publishing
Date: 06-2018
Publisher: Elsevier BV
Date: 05-2020
Publisher: American Association for the Advancement of Science (AAAS)
Date: 24-04-2020
Abstract: Fine-structure constant measurements 13 Ga ago, plus lower redshift data, test space-time variation of a fundamental constant.
Publisher: Oxford University Press (OUP)
Date: 21-04-2018
Publisher: MDPI AG
Date: 30-03-2017
Publisher: Springer Science and Business Media LLC
Date: 12-2021
DOI: 10.1038/S41567-021-01393-Y
Abstract: Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared with the Galaxy but much larger than the Earth. Here we report the results of the search for transient signals from the domain walls of axion-like particles by using the global network of optical magnetometers for exotic (GNOME) physics searches. We search the data, consisting of correlated measurements from optical atomic magnetometers located in laboratories all over the world, for patterns of signals propagating through the network consistent with domain walls. The analysis of these data from a continuous month-long operation of GNOME finds no statistically significant signals, thus placing experimental constraints on such dark matter scenarios.
Location: United States of America
No related grants have been discovered for Vincent Dumont.