87Sr lattice clock with inaccuracy below 10 -15.
ABSTRACT Aided by ultrahigh resolution spectroscopy, the overall systematic uncertainty of the 1S0-3P0 clock resonance for lattice-confined 87Sr has been characterized to 9 x 10(-16). This uncertainty is at a level similar to the Cs-fountain primary standard, while the potential stability for the lattice clocks exceeds that of Cs. The absolute frequency of the clock transition has been measured to be 429 228 004 229 874.0(1.1) Hz, where the 2.5 x 10(-15) fractional uncertainty represents the most accurate measurement of a neutral-atom-based optical transition frequency to date.
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ABSTRACT: We have measured the absolute frequency of the optical lattice clock based on 87Sr at PTB with an uncertainty of 3.9 × 10−16 using two caesium fountain clocks. This is close to the accuracy of todayʼs best realizations of the SI second. The absolute frequency of the 5 s2 1S0 – 5s5p 3P0 transition in 87Sr is 429 228 004 229 873.13(17) Hz. Our result is in excellent agreement with recent measurements performed in different laboratories worldwide. We improved the total systematic uncertainty of our Sr frequency standard by a factor of five and reach 3 × 10−17, opening new prospects for frequency ratio measurements between optical clocks for fundamental research, geodesy or optical clock evaluation.New Journal of Physics 07/2014; 16(7):073023. DOI:10.1088/1367-2630/16/7/073023 · 3.67 Impact Factor
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ABSTRACT: Progress in atomic, optical and quantum science has led to rapid improvements in atomic clocks. At the same time, atomic clock research has helped to advance the frontiers of science, affecting both fundamental and applied research. The ability to control quantum states of individual atoms and photons is central to quantum information science and precision measurement, and optical clocks based on single ions have achieved the lowest systematic uncertainty of any frequency standard. Although many-atom lattice clocks have shown advantages in measurement precision over trapped-ion clocks, their accuracy has remained 16 times worse. Here we demonstrate a many-atom system that achieves an accuracy of 6.4 × 10(-18), which is not only better than a single-ion-based clock, but also reduces the required measurement time by two orders of magnitude. By systematically evaluating all known sources of uncertainty, including in situ monitoring of the blackbody radiation environment, we improve the accuracy of optical lattice clocks by a factor of 22. This single clock has simultaneously achieved the best known performance in the key characteristics necessary for consideration as a primary standard-stability and accuracy. More stable and accurate atomic clocks will benefit a wide range of fields, such as the realization and distribution of SI units, the search for time variation of fundamental constants, clock-based geodesy and other precision tests of the fundamental laws of nature. This work also connects to the development of quantum sensors and many-body quantum state engineering (such as spin squeezing) to advance measurement precision beyond the standard quantum limit.Nature 01/2014; 506(7486). DOI:10.1038/nature12941 · 42.35 Impact Factor
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ABSTRACT: We present an investigation of two-color magneto-optical trap (MOT) based on cesium 6S 1/2 -6P 3/2 -8S 1/2 ladder-type atomic system, which employs the optical forces due to photon scattering from the excited states 6P 3/2 (F'=5)-8S 1/2 (F"=4) (794.6nm) transition, and replaces one pair of the three pairs of cooling laser beams operating on a single-photon red detuning to the 6S 1/2 (F=4)-6P 3/2 (F'=5) (852.3nm) transition in a conventional 3D MOT, and this two-color MOT can efficiently cool and trap atoms in a vapor cell on both the negative and positive sides of the two-photon resonance. We found an interesting phenomenon that when the 794.6nm cooling laser is tuned resonant with the 6P 3/2 (F'=5)-8S 1/2 (F"=4) transition and the intensity of 852.3nm cooling laser is too strong, the number of trapped atoms in the two-color MOT will be suppressed due to the heating from photons scattering. These works should be helpful to increasing optical thickness of trapped atoms and the practical applications of two-color MOT.