National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom.
National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom and School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Phys Rev Lett. 2014 Nov 21;113(21):210801. doi: 10.1103/PhysRevLett.113.210801. Epub 2014 Nov 17.
Singly ionized ytterbium, with ultranarrow optical clock transitions at 467 and 436 nm, is a convenient system for the realization of optical atomic clocks and tests of present-day variation of fundamental constants. We present the first direct measurement of the frequency ratio of these two clock transitions, without reference to a cesium primary standard, and using the same single ion of 171Yb+. The absolute frequencies of both transitions are also presented, each with a relative standard uncertainty of 6×10(-16). Combining our results with those from other experiments, we report a threefold improvement in the constraint on the time variation of the proton-to-electron mass ratio, μ/μ=0.2(1.1)×10(-16) yr(-1), along with an improved constraint on time variation of the fine structure constant, α/α=-0.7(2.1)×10(-17) yr(-1).
单离子化镱，其在 467nm 和 436nm 处具有超窄光学钟跃迁，是实现光学原子钟和检验现今基本常数变化的理想体系。我们首次直接测量了这两个钟跃迁的频率比，无需参考铯基准，并使用同一 171Yb+单离子。我们还给出了这两个跃迁的绝对频率，其相对标准不确定度均为 6×10(-16)。将我们的结果与其他实验的结果相结合，我们报告了质子与电子质量比 μ/μ 的时间变化的约束的三倍改善，其值为 0.2(1.1)×10(-16) yr(-1)，同时精细结构常数 α/α 的时间变化的约束也得到了改善，其值为-0.7(2.1)×10(-17) yr(-1)。
