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T. E. Chupp

Bio: T. E. Chupp is an academic researcher from Harvard University. The author has contributed to research in topics: Neutron & Avalanche photodiode. The author has an hindex of 7, co-authored 10 publications receiving 341 citations. Previous affiliations of T. E. Chupp include University of Michigan & Smithsonian Astrophysical Observatory.

Papers
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Journal ArticleDOI
TL;DR: The authors' data produce an upper limit (1
Abstract: We have performed a test of Lorentz invariance by searching for a time-dependent quadrupole splitting of Zeeman levels in $^{21}\mathrm{Ne}$. A component of the splitting at a twice the Earth's sidereal frequency (${\mathrm{\ensuremath{\Omega}}}_{\mathrm{S}}$) would suggest a preferred direction which affects the local physics of the $^{21}\mathrm{Ne}$ nucleus. The technique employs polarized $^{21}\mathrm{Ne}$ and $^{3}\mathrm{He}$ gases produced by spin exchange with laser optically pumped Rb. Both species are contained in the same glass cell, the $^{3}\mathrm{He}$ providing magnetometry and a monitor of systematic effects. Data from two runs produce an upper limit at the 1\ensuremath{\sigma} confidence level of 2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}21}$ eV (0.45\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$ Hz) on the Lorentz-invariance violating contribution to the binding energy. This result is comparable to that of the most precise previous experiment.

123 citations

Journal ArticleDOI
TL;DR: In this article, a stable-state noble gas Zeeman maser operating with $3 and $129 was realized by spin exchange with laser optically pumped Rb. In a two-cell setup maser conditions for both species can be optimized allowing a wide array of precision measurements.
Abstract: Steady-state noble gas Zeeman masers operating with $^{3}\mathrm{He}$ and $^{129}\mathrm{Xe}$ have been realized by spin exchange with laser optically pumped Rb. These masers can operate continuously for arbitrary lengths of time. For measurement intervals \ensuremath{\tau}=1000 to 10 000 s, frequency measurement precision for a phase locked $^{129}\mathrm{Xe}$ maser is shown to be better than 1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}2}$${\mathrm{\ensuremath{\tau}}}^{\mathrm{\ensuremath{-}}3/2}$ Hz. Startup transients are used to study gain characteristics. In a two-cell setup maser conditions for both species can be optimized allowing a wide array of precision measurements.

72 citations

Journal ArticleDOI
TL;DR: Observation de la coherence entre les 4 sous-niveaux magnetiques de 21 Ne en precession libre sur 4,5 h and detection directe de the composante quadripolaire de la relaxation de coherence constitue un test de the linearite de the mecanique quantique.
Abstract: We have observed coherence among the four magnetic sublevels of freely precessing $^{21}\mathrm{Ne}$ for times of 4.5 h. This has allowed direct detection of the quadrupole component of coherence relaxation and a test of linearity of quantum mechanics. The quadrupole component of relxation is evident in the different relaxation rates for the three lines of the NMR spectrum. Nonlinear corrections to quantum mechanics are found to be less than 1.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}26}$ of the binding energy per nucleon of $^{21}\mathrm{Ne}$.

58 citations

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TL;DR: The first demonstration of nuclear orientation of radon atoms is reported, using the nuclear-magnetic-resonance method, at the ISOLDE isotope separator of CERN.
Abstract: This paper reports the first demonstration of nuclear orientation of radon atoms. The method employed was spin exchange with potassium atoms polarized by optical pumping. The radon isotopes were produced at the ISOLDE isotope separator of CERN. The nuclear alignment of /sup 209/Rn and /sup 223/Rn has been measured by observation of ..gamma..-ray anisotropies and the magnetic dipole moment for /sup 209/Rn has been measured by the nuclear-magnetic-resonance method to be chemically bond..mu..chemically bond = 0.838 81(39)..mu../sub N/.

36 citations

Journal ArticleDOI
TL;DR: A measurement of elastic scattering of polarized electrons from polarized $^{3}\mathrm{He}$ confirmed that the nuclei in the electron beam had the expected polarization.
Abstract: We have developed a polarized $^{3}\mathrm{He}$ target for polarized electron scattering measurements. The target has a $^{3}\mathrm{He}$ density of 1.1\ifmmode\times\else\texttimes\fi{}${10}^{20}$ nuclei ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$, a total length of 7.5 cm and thin glass windows of 120--180 \ensuremath{\mu}m thickness. $^{3}\mathrm{He}$ polarization as large as 40% was produced, limited only by the available laser power. The $^{3}\mathrm{He}$ polarization was maintained during bombardment with up to 22 \ensuremath{\mu}A of 578 MeV electrons. A measurement of elastic scattering of polarized electrons from polarized $^{3}\mathrm{He}$ confirmed that the nuclei in the electron beam had the expected polarization. The polarization is produced by spin exchange with laser optically pumped Rb vapor, and the target design incorporates two separated volumes, one for optical pumping and the other for the electron bombardment. Extensions of this design are practical for fixed target electron scattering from polarized $^{3}\mathrm{He}$ planned for SLAC and CEBAF.

29 citations


Cited by
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TL;DR: A comprehensive survey of recent work on modified theories of gravity and their cosmological consequences can be found in this article, where the authors provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a selfcontained, comprehensive and up-to-date introduction to the subject as a whole.

3,674 citations

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TL;DR: Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging.
Abstract: The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein’s equivalence principle (EEP) is well supported by experiments such as the Eotvos experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.

3,394 citations

Journal ArticleDOI
Abstract: This article describes the various experimental bounds on the variation of the fundamental constants of nature. After a discussion of the role of fundamental constants, their definition and link with metrology, it reviews the various constraints on the variation of the fine-structure constant, the gravitational, weak- and strong-interaction couplings and the electron-to-proton mass ratio. The review aims (1) to provide the basics of each measurement, (2) to show as clearly as possible why it constrains a given constant, and (3) to point out the underlying hypotheses. Such an investigation is of importance in comparing the different results and in understanding the recent claims of the detection of a variation of the fine-structure constant and of the electron-to-proton mass ratio in quasar absorption spectra. The theoretical models leading to the prediction of such variation are also reviewed, including Kaluza-Klein theories, string theories, and other alternative theories. Cosmological implications of these results are also discussed. The links with the tests of general relativity are emphasized.

1,051 citations

Journal ArticleDOI
TL;DR: This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible.
Abstract: Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.

1,008 citations

Journal ArticleDOI
TL;DR: Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion.
Abstract: The status of experimental tests of general relativity and of theoretical frameworks for analysing them are reviewed. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eotvos experiment, tests of special relativity, and the gravitational redshift experiment. Future tests of EEP and of the inverse square law will search for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected to half a percent using the binary pulsar, and new binary pulsar systems may yield further improvements. When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.

828 citations