| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
|
| Initial Amendment Date: | July 25, 2012 |
| Latest Amendment Date: | June 18, 2014 |
| Award Number: | 1142032 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Vladimir Papitashvili
vpapita@nsf.gov (703)292-7425 OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | August 1, 2012 |
| End Date: | July 31, 2015 (Estimated) |
| Total Intended Award Amount: | $559,974.00 |
| Total Awarded Amount to Date: | $559,974.00 |
| Funds Obligated to Date: |
FY 2013 = $160,018.00 FY 2014 = $157,303.00 |
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
1 NASSAU HALL PRINCETON NJ US 08544-2001 (609)258-3090 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
Physics Dept., Washington Rd. Princeton NJ US 08544-2020 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): |
OFFICE OF MULTIDISCIPLINARY AC, PRECISION MEASUREMENTS, ANT Astrophys & Geospace Sci |
| Primary Program Source: |
01001314DB NSF RESEARCH & RELATED ACTIVIT 01001415DB NSF RESEARCH & RELATED ACTIVIT 0100XXXXDB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): | |
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
Lorentz symmetry, the feature of nature that makes experimental results independent of the orientation or the boost velocity of the laboratory through space, lies at the foundation of both the quantum field theory and the theory of general relativity. Their unification is regarded as one of the biggest, but yet unmet, challenges in physics. Special relativity postulates that all laws of physics are invariant under Lorentz transformations, which include ordinary rotations and changes in the velocity of a reference frame. Subsequently, quantum field theories all incorporated Lorentz Invariance in their basic structure. The force of gravity, unlike other fundamental forces, is characterized by a dimensionful coupling constant that introduces a characteristic energy of the Plank scale. However, the existence of such fixed high energy scale is not Lorentz-invariant; hence, tests of Lorentz symmetry attract a lot of interest as one of the most promising ways for searching experimental effects of the quantum gravity. Respective high-sensitivity experimental techniques were developed to search for a spatial anisotropy caused by Lorentz-violating spin interaction. Spatial anisotropy of an Earth laboratory is mainly defined by three effects: gravity, magnetic fields, and Earth rotation. Spin measurements are particularly sensitive to rotations which mimic Lorentz violating effects, while gravity affects the mechanical stability of the apparatus. In contrast, magnetic fields can be relatively easily shielded. Therefore, the most isotropic location for such experiments is at one of the geographic poles, where Earth rotation vector is parallel to the gravity vector. This award is to test Lorentz Invariance with unprecedented precision by deploying a very sensitive atomic spin sensor at the South Pole Station in Antarctica, where it is unaffected by the Earth's rotation. The experiment will constrain several possible forms of Lorentz violation in the sensitivity range where the effects of quantum gravity can be expected, improving existing limits by a factor of thousand. The project will attract wide attention as a simple test of the spatial isotropy of the Universe, and observation of any finite effects would certainly have a tremendous impact on the understanding of space-time shedding light on one of the most challenging problems in physics ? origin of gravity. The project will also involve training for the postdocs and students at the graduate and undergraduate levels.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The goal of the experiment was to perform a precision test of one of the fundamental predictions of the theory of relativity, that the speed of light is the same in all directions. To perform the most accurate test, the experimental apparatus was located at the Amundsen-Scott South Pole Station, close to the axis of Earth's rotation. This is the most symmetrical place on Earth. We looked for possible changes in the speed of light by monitoring their effect on Neon atoms contained in a special apparatus and illuminated with lasers. The experiment was operated for 2 years, collecting data mostly during the winter at the South Pole. Analysis of the data has allowed us to confirm that the speed of light is the same in all directions to an unprecedented precision, a few parts in 10^30, a quadrillion quadrillions. This confirms a basic prediction of Einstein's theory of relativity and sheds light on attempts to unify relativity with quantum mechanics. We also looked for other new physics effects, for example due to dark matter particles, by taking advantage of the unique location at the South Pole. This is the first precision atomic physics experiment performed at the Amundsen-Scott South Pole Station, it demonstrated the potential of this location for precision tests of fundamental physics.
Last Modified: 12/31/2015
Modified by: Michael V Romalis
Please report errors in award information by writing to: awardsearch@nsf.gov.
