Ashby N, Heavner T P, Jefferts S R, Parker T E, Radnaev A G, Dudin Y O
Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA.
Phys Rev Lett. 2007 Feb 16;98(7):070802. doi: 10.1103/PhysRevLett.98.070802.
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.
我们报告了基于铯原子钟和氢原子钟（频率标准）长达7年的比对，对广义相对论所基于的局部位置不变性（LPI）假设进行的迄今为止最灵敏的检验。最新结果给出的上限比之前最灵敏的检验小20多倍；这与LPI预测的零偏移一致。该结果基于美国国家标准与技术研究院（NIST）维护的四个氢脉泽的频率与四个独立的铯喷泉钟——一个在NIST，三个在欧洲——的精确比对，因为地球轨道偏心率导致地球表面太阳引力势发生变化。
