Bulletin of the American Physical Society
2005 36th Meeting of the Division of Atomic, Molecular and Optical Physics
Tuesday–Saturday, May 17–21, 2005; Lincoln, Nebraska
Session C2: Precision Tests of Relativity and Gravitation |
Hide Abstracts |
Sponsoring Units: PMTG Chair: Ronald L. Walsworth, Harvard-Smithsonian Center for Astrophysics Room: Burnham Yates Conference Center Ballroom II |
Wednesday, May 18, 2005 1:30PM - 2:06PM |
C2.00001: Lorentz and CPT Violation: Status and Prospects Invited Speaker: Lorentz and CPT symmetry is an intrinsic component of our best existing theories of nature, including QED, the Standard Model, and General Relativity. However, in an underlying theory that combines quantum physics with gravity, this invariance could be violated. The resulting physics emerging at presently accessible energies is described by the general effective field theory for Lorentz and CPT violation called the Standard-Model Extension (SME). Precision measurements using sensitive techniques from atomic and optical physics have the potential to reveal the experimental signals predicted by the SME. [Preview Abstract] |
Wednesday, May 18, 2005 2:06PM - 2:42PM |
C2.00002: A modern Michelson-Morley experiment using ultrastable optical resonators Invited Speaker: This talk will describe a modern version of the classic Michelson-Morley experiment testing the isotropy of light propagation and thus the foundations of Special Relativity. The latest experimental setup employs of an assembly of orthogonal ultrastable optical resonators mounted inside a liquid Helium cryostat, which itself is actively rotated using a high performance air-supported turntable. The cavity resonance frequencies are continuously monitored using monolithic Nd:YAG lasers and analyzed for periodic modulations indicating violations of Lorentz-invariance. Compared to pervious experiments using cryogenic optical resonators (COREs), but relying solely on Earth's rotation, this new version is expected to lead to orders of magnitude improvement in sensitivity to Lorentz-Invariance violation. We present the initial results of this experimental effort at the $\Delta $c($\theta )$/c $\sim $ 10$^{-16}$ level for an direction dependent variation of the speed of light and discuss the potential for future improvements. [Preview Abstract] |
Wednesday, May 18, 2005 2:42PM - 3:18PM |
C2.00003: Laboratory Tests of Newtonian Gravity Invited Speaker: Torsion balances provide a table-top experimental tool to test the equivalence principle and inverse square law of gravity, properties of gravity that have recently been called into question. Modern theories of quantum gravity predict new spatial dimensions that may lead to an observable violation of the inverse square law and new scalar interactions that violate both the equivalence principle and inverse square law. The dark energy that pervades the universe may lead to similar violations of these laws. Our group at the University of Washington has developed torsion balances to test these laws. We have experimental results that set new limits on the violation of the equivalence principle at length scales larger than one meter and that probe the inverse square law at distances as small as 50 microns. The latest results from our group will be presented. [Preview Abstract] |
Wednesday, May 18, 2005 3:18PM - 3:54PM |
C2.00004: The Gravity Probe B Relativity Mission Invited Speaker: The Gravity Probe B satellite was launched from Vandenberg Airforce Base on April 20, 2004. The satellite and its payload were designed to perform a high precision experimental test of the general theory of relativity. Measurements are now being made of the precession rates of the four cryogenic, electrostatically-supported, mechanical gyroscopes relative to the guide star, IM Pegasi. Simultaneously, using Very Long Baseline Interferometry, the proper motion of this guide star is being measured relative to extragalactic reference sources by a group at the Harvard-Simithsonian Center for Astrophysics. Combining these two measurements, the precession rate of the gyroscopes relative to the extragalactic reference sources may be determined, and this precession rate may be compared with the geodetic and frame-dragging precession rates as predicted by the general theory of relativity. The geodetic effect is due to the gravitational interaction of the spinning gyroscope with its orbital motion, while the frame-dragging effect is due to the gravitational interaction of the spinning gyroscopes with the Earth's angular momentum. In the 640 km circular, polar orbit, general relativity predicts that these precession rates will respectively be 6.6 arc seconds/year in the plane of the orbit and 41 milli-arc-seconds/year perpendicular to the plane of the orbit. The goal of the mission is to measure the precession rates of each of the four gyroscopes to an accuracy significantly better than 0.5 milli-arc-seconds/year. This talk will describe the payload and satellite hardware and discuss the method of measuring the orientation of the gyroscope spin axis relative to the guide star as well as measurements designed to place tight limits on potential systematic errors. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700