oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
STE-QUEST Mission and System Design - Overview after completion of Phase-A  [PDF]
Gerald Hechenblaikner,Marc-Peter Hess,Marianna Vitelli,Jan Beck
Physics , 2013, DOI: 10.1007/s10686-014-9373-6
Abstract: STE-QUEST is a fundamental science mission which is considered for launch within the Cosmic Vision programme of the European Space Agency (ESA). Its main scientific objectives relate to probing various aspects of Einstein's theory of general relativity by measuring the gravitational red-shift of the earth, the moon and the sun as well as testing the weak equivalence principle to unprecedented accuracy. In order to perform the measurements, the system features a spacecraft equipped with two complex instruments, an atomic clock and an atom interferometer, a ground-segment encompassing several ground-terminals collocated with the best available ground atomic clocks, and clock comparison between space and ground via microwave and optical links. The baseline orbit is highly eccentric and exhibits strong variations of incident solar flux, which poses challenges for thermal and power subsystems in addition to the difficulties encountered by precise-orbit-determination at high altitudes. The mission assessment and definition phase (Phase-A) has recently been completed and this paper gives a concise overview over some system level results.
STE-QUEST - Test of the Universality of Free Fall Using Cold Atom Interferometry  [PDF]
D. Aguilera,H. Ahlers,B. Battelier,A. Bawamia,A. Bertoldi,R. Bondarescu,K. Bongs,P. Bouyer,C. Braxmaier,L. Cacciapuoti,C. Chaloner,M. Chwalla,W. Ertmer,M. Franz,N. Gaaloul,M. Gehler,D. Gerardi,L. Gesa,N. Gürlebeck,J. Hartwig,M. Hauth,O. Hellmig,W. Herr,S. Herrmann,A. Heske,A. Hinton,P. Ireland,P. Jetzer,U. Johann,M. Krutzik,A. Kubelka,C. L?mmerzahl,A. Landragin,I. Lloro,D. Massonnet,I. Mateos,A. Milke,M. Nofrarias,M. Oswald,A. Peters,K. Posso-Trujillo,E. Rasel,E. Rocco,A. Roura,J. Rudolph,W. Schleich,C. Schubert,T. Schuldt,S. Seidel,K. Sengstock,C. F. Sopuerta,F. Sorrentino,D. Summers,G. M. Tino,C. Trenkel,N. Uzunoglu,W. von Klitzing,R. Walser,T. Wendrich,A. Wenzlawski,P. We?els,A. Wicht,E. Wille,M. Williams,P. Windpassinger,N. Zahzam
Physics , 2013, DOI: 10.1088/0264-9381/31/11/115010
Abstract: The theory of general relativity describes macroscopic phenomena driven by the influence of gravity while quantum mechanics brilliantly accounts for microscopic effects. Despite their tremendous individual success, a complete unification of fundamental interactions is missing and remains one of the most challenging and important quests in modern theoretical physics. The STE-QUEST satellite mission, proposed as a medium-size mission within the Cosmic Vision program of the European Space Agency (ESA), aims for testing general relativity with high precision in two experiments by performing a measurement of the gravitational redshift of the Sun and the Moon by comparing terrestrial clocks, and by performing a test of the Universality of Free Fall of matter waves in the gravitational field of Earth comparing the trajectory of two Bose-Einstein condensates of Rb85 and Rb87. The two ultracold atom clouds are monitored very precisely thanks to techniques of atom interferometry. This allows to reach down to an uncertainty in the E\"otv\"os parameter of at least 2x10E-15. In this paper, we report about the results of the phase A mission study of the atom interferometer instrument covering the description of the main payload elements, the atomic source concept, and the systematic error sources.
Quantum Tests of the Einstein Equivalence Principle with the STE-QUEST Space Mission  [PDF]
Brett Altschul,Quentin G. Bailey,Luc Blanchet,Kai Bongs,Philippe Bouyer,Luigi Cacciapuoti,Salvatore Capozziello,Naceur Gaaloul,Domenico Giulini,Jonas Hartwig,Luciano Iess,Philippe Jetzer,Arnaud Landragin,Ernst Rasel,Serge Reynaud,Stephan Schiller,Christian Schubert,Fiodor Sorrentino,Uwe Sterr,Jay D. Tasson,Guglielmo M. Tino,Philip Tuckey,Peter Wolf
Physics , 2014, DOI: 10.1016/j.asr.2014.07.014
Abstract: We present in detail the scientific objectives in fundamental physics of the Space-Time Explorer and QUantum Equivalence Space Test (STE-QUEST) space mission. STE-QUEST was pre-selected by the European Space Agency together with four other missions for the cosmic vision M3 launch opportunity planned around 2024. It carries out tests of different aspects of the Einstein Equivalence Principle using atomic clocks, matter wave interferometry and long distance time/frequency links, providing fascinating science at the interface between quantum mechanics and gravitation that cannot be achieved, at that level of precision, in ground experiments. We especially emphasize the specific strong interest of performing equivalence principle tests in the quantum regime, i.e. using quantum atomic wave interferometry. Although STE-QUEST was finally not selected in early 2014 because of budgetary and technological reasons, its science case was very highly rated. Our aim is to expose that science to a large audience in order to allow future projects and proposals to take advantage of the STE-QUEST experience.
Probing the Flyby Anomaly with the future STE-QUEST mission  [PDF]
Jorge Páramos,Gerald Hechenblaikner
Physics , 2012, DOI: 10.1016/j.pss.2013.02.005
Abstract: In this study, we demonstrate that the flyby anomaly, an unexpected acceleration detected in some of the gravitational assists of the Galileo, NEAR, Cassini and Rosetta spacecraft, could be probed by accurate orbital tracking available in the proposed Space-Time Explorer and Quantum Equivalence Principle Space Test (STE- QUEST); following a recent work, we focus on the similarity between an hyperbolic flyby and the perigee passage in a highly elliptic orbit of the latter, as well as its Global Navigation Satellite System precise orbital determination capabilities.
The Association of the Moon and the Sun with Large Earthquakes  [PDF]
Lyndie Chiou
Physics , 2012,
Abstract: The role of the moon in triggering earthquakes has been studied since the early 1900s. Theory states that as land tides swept by the moon cross fault lines, stress in the Earth's plates intensifies, increasing the likelihood of small earthquakes. This paper studied the association of the moon and sun with larger magnitude earthquakes (magnitude 5 and greater) using a worldwide dataset from the USGS. Initially, the positions of the moon and sun were considered separately. The moon showed a reduction of 1.74% (95% confidence) in earthquakes when it was 10 hours behind a longitude on earth and a 1.62% increase when it was 6 hours behind. The sun revealed even weaker associations (<1%). Binning the data in 6 hours quadrants (matching natural tide cycles) reduced the associations further. However, combinations of moon-sun positions displayed significant associations. Cycling the moon and sun in all possible quadrant permutations showed a decrease in earthquakes when they were paired together on the East and West horizons of an earthquake longitude (4.57% and 2.31% reductions). When the moon and sun were on opposite sides of a longitude, there was often a small (about 1%) increase in earthquakes. Reducing the bin size from 6 hours to 1 hour produced noisy results. By examining the outliers in the data, a pattern emerged that was independent of earthquake longitude. The results showed a significant decrease (3.33% less than expected) in earthquakes when the sun was located near the moon. There was an increase (2.23%) when the moon and sun were on opposite sides of the Earth. The association with earthquakes independent of terrestrial longitude suggests that the combined moon-sun tidal forces act deep below the Earth's crust where circumferential forces are weaker.
Accounting for the Sun and the Moon in Fermi-LAT Analysis  [PDF]
Gudlaugur Johannesson,Elena Orlando,for the Fermi-LAT collaboration
Physics , 2013,
Abstract: The Sun and the Moon are quiescent gamma-ray sources that are clearly detectable in Fermi-LAT data. While moving through the sky, the Sun and the Moon can be a significant background in the analysis of Fermi-LAT data if they pass through the region of interest. Accurate modeling of their intensity is needed in this case, accounting for the correct exposure of their track along the sky. We present the Solar System Tools (SST) which calculate the templates of the Sun's and the Moon's intensity in the sky for a given observing period and a model of their steady emission. These tools are available in the standard Fermi-LAT Science Tools.
Moon and Sun shadowing effect in the MACRO detector  [PDF]
MACRO Collaboration
Physics , 2003, DOI: 10.1016/S0927-6505(03)00169-5
Abstract: Using data collected by the MACRO experiment from 1989 to the end of its operations in 2000, we have studied in the underground muon flux the shadowing effects due to both the Moon and the Sun. We have observed the Moon shadowing effect with a significance of 6.5 sigma and the Sun shadowing effect with a significance of 4.3 sigma. The observed displacement of the Sun shadow, due to the configurations of the solar and interplanetary magnetic fields, has been used to quote the antiproton/proton flux limits for primaries of about 20 TeV energy.
Moon and Sun Shadowing Observed by the MACRO Detector  [PDF]
N. Giglietto,for the MACRO collaboration
Physics , 1999,
Abstract: Using over 40 million muons collected since 1989 by the MACRO detector we have searched for a depletion of muons coming from the direction of the Moon due to primary cosmic rays striking the Moon. We observe this Moon shadow in the expected position with a statistical significance of more than 5 standard deviations. We have analyzed the same data for an analogous Sun shadow, and have found a signal with a significance of about 4 standard deviations. The Sun shadow is displaced from the Sun's position by about 0.6 degrees North in ecliptic coordinates. This displacement is compatible with a deflection of primary cosmic rays due to the Interplanetary Magnetic Field in the 10-20 TeV primary energy range which is relevant to the underground muons observed by MACRO.
Study of the Shadows of the Moon and the Sun with VHE Cosmic Rays  [PDF]
R. Atkins,W. Benbow,D. Berley,M. -L. Chen,D. G. Coyne,R. S. Delay,B. L. Dingus,D. E. Dorfan,R. W. Ellsworth,D. Evans,A. Falcone,L. Fleysher,R. Fleysher,G. Gisler,J. A. Goodman,T. J. Haines,C. M. Hoffman,S. Hugenberger,L. A. Kelley,I. Leonor,J. Macri,M. McConnell,J. F. McCullough,J. E. McEnery,R. S. Miller,A. I. Mincer,M. F. Morales,P. Nemethy,J. M. Ryan,M. Schneider,B. Shen,A. Shoup,G. Sinnis,A. J. Smith,G. W. Sullivan,T. N. Thompson,O. T. Tumer,K. Wang,M. O. Wascko,S. Westerhoff,D. A. Williams,T. Yang,G. B. Yodh
Physics , 1999,
Abstract: Milagrito, a prototype for the Milagro detector, operated for 15 months in 1997-8 and collected 8.9 billion events. It was the first extensive air shower (EAS) array sensitive to showers intiated by primaries with energy below 1 TeV. The shadows of the sun and moon observed with cosmic rays can be used to study systematic pointing shifts and measure the angular resolution of EAS arrays. Below a few TeV, the paths of cosmic rays coming toward the earth are bent by the helio- and geo-magnetic fields. This is expected to distort and displace the shadows of the sun and the moon. The moon shadow, offset from the nominal (undeflected) position, has been observed with high statistical significance in Milagrito. This can be used to establish energy calibrations, as well as to search for the anti-matter content of the VHE cosmic ray flux. The shadow of the sun has also been observed with high significance.
Differential atom interferometry with $^{87}$Rb and $^{85}$Rb for testing the UFF in STE-QUEST  [PDF]
C Schubert,J Hartwig,H Ahlers,K Posso-Trujillo,N. Gaaloul,U. Velte,A. Landragin,A. Bertoldi,B. Battelier,P. Bouyer,F. Sorrentino,G. M. Tino,M. Krutzik,A. Peters,S. Herrmann,C. L?mmerzahl,L. Cacciapouti,E. Rocco,K. Bongs,W. Ertmer,E. M. Rasel
Physics , 2013,
Abstract: In this paper we discuss in detail an experimental scheme to test the universality of free fall (UFF) with a differential $^{87}$Rb / $^{85}$Rb atom interferometer applicable for extended free fall of several seconds in the frame of the STE-QUEST mission. This analysis focuses on suppression of noise and error sources which would limit the accuracy of a violation measurement. We show that the choice of atomic species and the correctly matched parameters of the interferometer sequence are of utmost importance to suppress leading order phase shifts. In conclusion we will show the expected performance of $2$ parts in $10^{15}$ of such an interferometer for a test of the UFF.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.