Measurement of the blackbody radiation shift of the Cs-133 hyperfine transition in an atomic fountain

摘要

We used a Cs fountain to measure the Stark shift of the ground-state hyperfine transition frequency in cesium (9.2 GHz) due to the electric field of the blackbody radiation. The relative shift at 300 K deduced from our measurements, including the leading and the second-order term in temperature, is (-1.45+/-0.09)x10(-14) and agrees with our recent theoretical evaluation (-1.51+/-0.07)x10(-14) [Micalizio Phys. Rev. A 69, 053401 (2004)]. These values differ from that currently used (-1.735+/-0.003)x10(-14), with significant implications on frequency standards accuracy, on clocks comparison and on a variety of high-precision physics tests, such as the time stability of fundamental constants.