Testing Local Position Invariance with Four Cesium-Fountain Primary Frequency Standards and Four NIST Hydrogen Masers

Journal Article · Fri Feb 16 00:00:00 EST 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.98.070802· OSTI ID:20955460

Ashby, N; Heavner, T P; Jefferts, S R; Parker, T E; Radnaev, A G; Dudin, Y O ^[1]

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1. Department of Physics, University of Colorado, Boulder, Colorado 80309-0390 (United States)

We report the most sensitive tests to date of the assumption of local position invariance (LPI) underlying general relativity, based on a 7 yr comparison of cesium and hydrogen atomic clocks (frequency standards). The latest results place an upper limit that is over 20 times smaller than the previous most sensitive tests; this is consistent with the null shift predicted by LPI. The result is based on precise comparisons of frequencies of four hydrogen masers maintained by NIST, with four independent Cs fountain clocks--one at NIST and three in Europe--as the Sun's gravitational potential at Earth's surface varies due to Earth's orbital eccentricity.

• OSTI ID: 20955460
• Journal Information: Physical Review Letters, Vol. 98, Issue 7; Other Information: DOI: 10.1103/PhysRevLett.98.070802; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMIC CLOCKS
CESIUM
GENERAL RELATIVITY THEORY
HYDROGEN
MASERS