Chronometric measurements in geodesy and geophysics

2020 ◽  
Author(s):  
Pacôme Delva ◽  
Guillaume Lion
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
High Spatial Resolution ◽  
Relativistic Effects ◽  
Atomic Clocks ◽  
Fundamental Physics ◽  
Geodynamic Processes ◽  
New Ideas ◽  
Mass Transfers

<p>At the beginning of the 20th century the theories of special and general relativity were developed by Einstein and his contemporaries. These physical theories revolutionize our conceptions of time and of the measurement of time. The atomic clocks, which appeared in the 1950s, are so accurate and stable that it is now essential to take into account many relativistic effects. The development and worldwide comparisons of such atomic clocks allowed for some of the most stringent of fundamental physics, as well as new ideas for the search of dark matter. On a more applied level, when taking general relativity for granted, distant comparisons of atomic clocks can be used for navigation and positioning, as well as the determination of the geopotential. I will show how the chronometric observables can fit and be used within the context of classical geodesy and geophysics, presenting various applications: determination of the geopotential with high spatial resolution, vertical reference system, and discussing the possible applications associated to the geodynamic processes related to mass transfers.</p>

scholarly journals Development of a space cold atom clock

2020 ◽  
Vol 7 (12) ◽  
pp. 1828-1836
Author(s):  
Wei Ren ◽  
Tang Li ◽  
Qiuzhi Qu ◽  
Bin Wang ◽  
Lin Li ◽  
...  
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Cold Atoms ◽  
Cold Atom ◽  
Deep Space ◽  
Fundamental Physics ◽  
Time Frequency ◽  
Frequency Standards ◽  
Scientific Experiments ◽  
Primary Frequency

Abstract Atomic clocks with cold atoms play important roles in the field of fundamental physics as well as primary frequency standards. Operating such cold atom clocks in space paves the way for further exploration in fundamental physics, for example dark matter and general relativity. We developed a space cold atom clock (SCAC), which was launched into orbit with the Space Lab TG-2 in 2016. Before it deorbited with TG-2 in 2019, the SCAC had been working continuously for almost 3 years. During the period in orbit, many scientific experiments and engineering tests were performed. In this article, we summarize the principle, development and in-orbit results. These works provide the basis for construction of a space-borne time-frequency system in deep space.

scholarly journals EXPERIMENTAL DESIGN FOR THE LATOR MISSION

2004 ◽  
Vol 13 (10) ◽  
pp. 2035-2063 ◽  
Author(s):  
SLAVA G. TURYSHEV ◽  
MICHAEL SHAO ◽  
KENNETH L. NORDTVEDT
Keyword(s):  
Experimental Design ◽  
Relativistic Effects ◽  
Communication Technologies ◽  
Range Interaction ◽  
Fundamental Physics ◽  
Long Baseline ◽  
Expected Performance ◽  
Long Range Interaction ◽  
Improve Determination

This paper discusses experimental design for the Laser Astrometric Test Of Relativity (LATOR) mission. LATOR is designed to reach unprecedented accuracy of 1 part in 108 in measuring the curvature of the solar gravitational field as given by the value of the key Eddington post-Newtonian parameter γ. This mission will demonstrate the accuracy needed to measure effects of the next post-Newtonian order (∝G2) of light deflection resulting from gravity's intrinsic non-linearity. LATOR will provide the first precise measurement of the solar quadrupole moment parameter, J2, and will improve determination of a variety of relativistic effects including Lense–Thirring precession. The mission will benefit from the recent progress in the optical communication technologies — the immediate and natural step above the standard radio-metric techniques. The key element of LATOR is a geometric redundancy provided by the laser ranging and long-baseline optical interferometry. We discuss the mission and optical designs, as well as the expected performance of this proposed mission. LATOR will lead to very robust advances in the tests of fundamental physics: this mission could discover a violation or extension of general relativity, or reveal the presence of an additional long range interaction in the physical law. There are no analogs to the LATOR experiment; it is unique and is a natural culmination of solar system gravity experiments.

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

scholarly journals Dark matter and fundamental physics with the Cherenkov Telescope Array

2013 ◽  
Vol 43 ◽  
pp. 189-214 ◽  
Author(s):  
M. Doro ◽  
J. Conrad ◽  
D. Emmanoulopoulos ◽  
M.A. Sànchez-Conde ◽  
J.A. Barrio ◽  
...  
Keyword(s):  
Dark Matter ◽  
Fundamental Physics ◽  
Telescope Array ◽  
Cherenkov Telescope

Characterization and Control of Copper CMP with Optoacoustic Metrology

2001 ◽  
Vol 671 ◽  
Author(s):  
Michael Gostein ◽  
Paul Lefevre ◽  
Alex A. Maznev ◽  
Michael Joffe
Keyword(s):  
Film Thickness ◽  
Spatial Resolution ◽  
Chemical Mechanical Polishing ◽  
High Spatial Resolution ◽  
Mechanical Polishing ◽  
Length Measurement ◽  
And Control ◽  
Non Destructive

ABSTRACTWe discuss applications of optoacoustic film thickness metrology for characterization of copper chemical-mechanical polishing (CMP). We highlight areas where the use of optoacoustics for CMP characterization provides data complementary to that obtained by other techniques because of its ability to directly measure film thickness with high spatial resolution in a rapid, non-destructive manner. Examples considered include determination of planarization length, measurement of film thickness at intermediate stages of polish, and measurement of arrays of metal lines.

scholarly journals Testing General Relativity with Atomic Clocks

2009 ◽  
Vol 148 (1-4) ◽  
pp. 233-247 ◽  
Author(s):  
S. Reynaud ◽  
C. Salomon ◽  
P. Wolf
Keyword(s):  
General Relativity ◽  
Atomic Clocks

scholarly journals Precision Determination of the Mass Function of Dark Matter Halos

2006 ◽  
Vol 646 (2) ◽  
pp. 881-885 ◽  
Author(s):  
Michael S. Warren ◽  
Kevork Abazajian ◽  
Daniel E. Holz ◽  
Luis Teodoro
Keyword(s):  
Dark Matter ◽  
Mass Function ◽  
Dark Matter Halos ◽  
Precision Determination

scholarly journals The emergence of the red sequence at z~2 seen through galaxy clustering in the UKIDSS UDS

2012 ◽  
Vol 8 (S295) ◽  
pp. 105-108
Author(s):  
William G. Hartley ◽  
Omar Almaini ◽  
Alice Mortlock ◽  
Chris Conselice ◽  
Keyword(s):  
Dark Matter ◽  
Cross Correlation ◽  
Near Infrared ◽  
Correlation Technique ◽  
Dark Matter Halos ◽  
Star Forming ◽  
Deep Survey ◽  
Cross Correlation Technique ◽  
Infrared Survey

AbstractWe use the UKIDSS Ultra-Deep Survey, the deepest degree-scale near-infrared survey to date, to investigate the clustering of star-forming and passive galaxies to z ~ 3.5. Our new measurements include the first determination of the clustering for passive galaxies at z > 2, which we achieve using a cross-correlation technique. We find that passive galaxies are the most strongly clustered, typically hosted by massive dark matter halos with Mhalo > 1013 M⊙ irrespective of redshift or stellar mass. Our findings are consistent with models in which a critical halo mass determines the transition from star-forming to passive galaxies.

A Tale of Two Infinities

2021 ◽  
Author(s):  
Gianfranco Bertone
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Traditional Approach ◽  
Fundamental Physics ◽  
Modern Cosmology ◽  
Nobel Prize In Physics ◽  
The Universe ◽  
Modern Astronomy

The spectacular advances of modern astronomy have opened our horizon on an unexpected cosmos: a dark, mysterious Universe, populated by enigmatic entities we know very little about, like black holes, or nothing at all, like dark matter and dark energy. In this book, I discuss how the rise of a new discipline dubbed multimessenger astronomy is bringing about a revolution in our understanding of the cosmos, by combining the traditional approach based on the observation of light from celestial objects, with a new one based on other ‘messengers’—such as gravitational waves, neutrinos, and cosmic rays—that carry information from otherwise inaccessible corners of the Universe. Much has been written about the extraordinary potential of this new discipline, since the 2017 Nobel Prize in physics was awarded for the direct detection of gravitational waves. But here I will take a different angle and explore how gravitational waves and other messengers might help us break the stalemate that has been plaguing fundamental physics for four decades, and to consolidate the foundations of modern cosmology.

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