Abstract
Repeated measurements of the frequency ratio of 199Hg + and 27A1+ singleatom optical clocks over the course of a year yield a constraint on the possible present-era temporal variation of the fine-structure constant a. The time variation of the measured ratio corresponds to a time variation in the fine structure constant of ά/α = (-1.6 ± 2.3) × 10-17/year, consistent with no change. The frequency ratio of these clocks was measured with a fractional uncertainty of 5.2 × 10-17. Stability simulations for optical clocks whose probe period is limited by 1/f-noise in the laser local oscillator provide an estimate of the optimal probe period, as well as a modified expression for the theoretical clock stability.
Original language | English |
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Title of host publication | Proceedings of the 7th Symposium on Frequency Standards and Metrology, ISFSM 2008 |
Pages | 20-33 |
Number of pages | 14 |
Publication status | Published - 2009 |
Event | 7th Symposium on Frequency Standards and Metrology, ISFSM 2008 - Pacific Grove, CA, United States Duration: 5 Oct 2008 → 11 Oct 2008 |
Conference
Conference | 7th Symposium on Frequency Standards and Metrology, ISFSM 2008 |
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Country/Territory | United States |
City | Pacific Grove, CA |
Period | 5/10/08 → 11/10/08 |