An Atomic Clock with 10
            <sup>–18</sup>
            Instability

Hinkley, N.; Sherman, Jeffrey A.; Phillips, Nathaniel B.; Schioppo, M.; Lemke, Nathan D.; Beloy, K.; Pizzocaro, Marco; Oates, C. W.; Ludlow, Andrew D.

doi:10.1126/science.1240420

Cited by 766 publications

(688 citation statements)

References 38 publications

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“…Optical lattice fre quency standards have now demonstrated systematic fractional uncertainties at the 10 −17 -10 −18 level [5] and also an unprec edented frequency stability [23] opening the path for frequency comparisons beyond the uncertainty of the realization of the SI units in hundreds of seconds [24]. In particular, different groups developed ytterbium optical lattice frequency stand ards worldwide [23][24][25][26] and the spin and angular momentum forbidden transition S 1 0 -P 3 0 of ytterbium 171 at 578 nm is recommended as a secondary representation of the SI second by the International Committee for Weights and Measures (CIPM). Absolute frequency measurement of this transition has been performed relative to the realization of the second with caesium standards at the National Institute of Standards and Technology (NIST) [8], at the National Metrology Institute of Japan (NMIJ) [27,28], and at the Korea Research Institute of Standards and Science (KRISS) [26].…”

Section: Introductionmentioning

confidence: 99%

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

et al. 2017

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We report the absolute frequency measurement of the unperturbed transition S 1 0 -P 3 0 at 578 nm in 171 Yb realized in an optical lattice frequency standard relative to a cryogenic caesium fountain. The measurement result is 518 295 836 590 863.59(31) Hz with a relative standard uncertainty of 5.9 10 16 × − . This value is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the International System of Units.

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Section: Introductionmentioning

confidence: 99%

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

et al. 2017

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“…about two orders of magnitude improvement in accuracy is needed to test the alpha-dipole hypothesis. Current-best optical-clocks approach fractional uncertainty of ∼ 10 −18 [6][7][8]. However, the transitions used in these clocks are not sufficiently sensitive to the variation of α [9].…”

Section: Ionmentioning

confidence: 99%

Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

2015

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We study the Ho 14+ ion as a candidate for extremely accurate and stable optical atomic clock which is sensitive to the time variation of the fine structure constant. We demonstrate that the proposed system has all desired features including relatively strong optical electric dipole and magnetic dipole transitions which can be used for cooling and detection. Zero quadrupole moments for the relevant states in the clock transition allows interrogating multiple ions to improve the clock stability.PACS numbers: 06.30. Ft, 06.20.Jr, 31.15.A, 32.30.Jc Theories unifying gravity with other fundamental interactions suggest a possibility for fundamental constants to vary in space or time (see, e.g. [1]). Searching for variation of the fundamental constants is an important way of testing these theories and finding new physics beyond standard model. Laboratory measurements limit the rate at which the fine structure constant α (α = e 2 /hc) varies in time to about 10 −17 per year [2,3]. On the other hand, the analysis of quasar absorption spectra shows that the fine structure constant may vary on astronomical scale along a certain direction in space forming the so called alpha-dipole [4]. Earth movement in the framework of the alpha-dipole (towards area of bigger alpha) 4f 6 5s 4f 5 s 2~4 0000 cm -1clock hfs-E1 λ~400 nm 6 H 5/2 (5) IonGround state Clock state Energy (cm −1 ) Er 14+ 4f 7 5s J = 4 4f 6 5s 2 J = 0 18555 Dy 10+ 4f 7 5p J = 3 4f 6 5p 2 J = 0 20835 Ho 14+ 4f 6 5s J = 0.5 4f 5 5s 2 J = 2.5 23800 would lead to the local time variation of α on the scale of 10 −19 per year [5]. To test the alpha-dipole hypothesis in terrestrial studies one needs a better accuracy in the laboratory measurements. The current best limit on the local time variation of α has been obtained by comparing Al + and Hg + optical clocks [2]. The result of this comparison limits time variation of alpha to (∂α/∂t)/α = (−1.6±2.3)×10 −17 yr −1 [2]), i.e. about two orders of magnitude improvement in accuracy is needed to test the alpha-dipole hypothesis. Current-best optical-clocks approach fractional uncertainty of ∼ 10 −18 [6][7][8]. However, the transitions used in these clocks are not sufficiently sensitive to the variation of α [9]. If α does change in time, the relative change δω/ω of the clock frequencies in any given period of time would be about an order of magnitude smaller than relative change in δα/α.It has been suggested in [10] to use highly-charged ions (HCI) as extremely accurate atomic clocks to probe possible variation of α. While HCIs are less sensitive to external perturbations due to their compact size, their sensitivity to variation of α is enhanced due to larger relativistic effects. In spite of the general trend of increasing energy intervals in HCIs, it is still possible to find clock transitions which are in optical range. This is due to electron energy level crossing while moving from the Modelung to the Coulomb level ordering with increasing

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“…Proposed in 2001 [21][22], OLCs made tremendous progress in the last decade. OLCs have demonstrated unprecedented frequency stabilities of a few 10 −16 / √ τ and a record accuracy below 10 −17 [1], overcoming the best ion clocks [1,[23][24][25][26]. With current improvement in laser stabilization, OLCs are expected to reach a QPN limited stability on the order of 10 −17 / √ τ within a few years, thus enabling even better characterization of systematic effects.…”

Section: Optical Lattice Clocksmentioning

confidence: 99%

Atomic fountains and optical clocks at SYRTE: Status and perspectives

Abgrall

Chupin

Sarlo

et al. 2015

Comptes Rendus. Physique

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In this article, we report on the work done with the LNE-SYRTE atomic clock ensemble during the last 10 years. We cover progress made in atomic fountains and in their application to timekeeping. We also cover the development of optical lattice clocks based on strontium and on mercury. We report on tests of fundamental physical laws made with these highly accurate atomic clocks. We also report on work relevant to a future possible redefinition of the SI second. IntroductionResearch on highly accurate atomic frequency standards and their applications is making fast and steady progress. The quest for ever increased accuracy is advancing hand in hand with advances in quantum physics, with better understanding and manipulation of atomic systems, with exploration of fundamental laws of nature and with the development of important services and infrastructures for science and society. The quest for increased accuracy is also a powerful incentive to innovation in such areas as lasers, laser stabilization, low noise electronics, stable oscillators, low noise detection of optical signals, fiber devices and cold-atom based instrumentation for ground or space applications. Finally, in addition to enhancing existing applications, improved accuracy leads to new applications.This article focuses on key achievements and trends of the last 10 years. Over this period of time, the first generation of laser-cooled standards, using the atomic fountain geometry, reached maturity and had large impact on international timekeeping. The typical accuracy of these frequency standards, 2 parts in 10 16 , is now permanently accessible both locally and globally. At the same time, a new generation of optical clocks showed tremendous and steady improvement, gaining more than two orders of magnitude in a decade. To date, an accuracy of 6.4 × 10 −18 [1] was reported. Similarly, major improvements occurred in many other aspects of optical frequency metrology, notably in optical frequency combs and optical fiber links.In this article, we will report on developments of the LNE-SYRTE atomic clock ensemble since our 2004 report in the Special Issue of the Comptes Rendus de l'Académie des sciences on Fundamental Metrology [2]. This work exemplifies many of the above mentioned features of research on highly accurate atomic frequency standards. We will focus on frequency standards and their impact on timescales and timekeeping, on clock comparisons, including optical-to-microwave comparisons with combs, and their applications. Several

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An Atomic Clock with 10 ^–18 Instability

Cited by 766 publications

References 38 publications

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

Atomic fountains and optical clocks at SYRTE: Status and perspectives

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An Atomic Clock with 10 –18 Instability

Cited by 766 publications

References 38 publications

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of171Yb

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of171Yb

Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

Atomic fountains and optical clocks at SYRTE: Status and perspectives

Contact Info

Product

Resources

About

An Atomic Clock with 10 ^–18 Instability

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb