Direct comparison of optical lattice clocks with an intercontinental baseline of 9000  km

Hachisu, Hidekazu; Fujieda, Miho; Nagano, S.; Gotoh, Tadahiro; Nogami, Asahiko; Ido, T.; Falke, Stephan; Huntemann, N.; Grebing, Christian; Lipphardt, B.; Lisdat, Ch.; Piester, D.

doi:10.1364/ol.39.004072

Cited by 45 publications

(26 citation statements)

References 22 publications

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“…Also, they are highly interesting for frequency metrology and time keeping in creating a consistent worldwide network of the next-generation ultraprecise clocks. Although comparisons at the full performance level of state-of-the-art optical clocks are possible on a continental scale [18,19] through a few specialized optical fiber links [20][21][22], intercontinental links are so far restricted to satellite-based methods that cannot fully exploit the clock performance [23]. A transfer standard enables world-wide interconnections between optical clocks and will thus benefit the efforts towards a redefinition of the SI second.…”

Section: Pacs Numbersmentioning

confidence: 99%

Transportable Optical Lattice Clock with7×10−17Uncertainty

et al. 2017

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We present a transportable optical clock (TOC) with 87 Sr. Its complete characterization against a stationary lattice clock resulted in a systematic uncertainty of 7.4 × 10 −17 which is currently limited by the statistics of the determination of the residual lattice light shift. The measurements confirm that the systematic uncertainty is reduceable to below the design goal of 1 × 10 −17 . The instability of our TOC is 1.3 × 10 −15 / √ τ . Both, the systematic uncertainty and the instability are to our best knowledge currently the best achieved with any type of transportable clock. For autonomous operation the TOC is installed in an air-conditioned car-trailer. It is suitable for chronometric leveling with sub-meter resolution as well as intercontinental cross-linking of optical clocks, which is essential for a redefiniton of the SI second. In addition, the TOC will be used for high precision experiments for fundamental science that are commonly tied to precise frequency measurements and it is a first step to space borne optical clocks. PACS numbers:The best clocks in the world reach a fractional systematic uncertainty at the low 10 −18 level [1-4] and instabilities near or even below 10 2,[4][5][6], surpassing the clocks realizing the SI second in both by two orders of magnitude. This has triggered a discussion about a redefinition of the SI second [7,8], pushes the frontiers of precision spectroscopy and tests fundamental physics [9][10][11][12][13][14], and enables chronometric leveling [15][16][17][18][19], where gravitational redshifts are exploited to measure height differences.So far, the operation of optical clocks has been constrained to laboratories. However, transportable clocks are required for the necessary flexibility in the choice of measurement sites for applications like chronometric leveling. Also, they are highly interesting for frequency metrology and time keeping in creating a consistent worldwide network of the next-generation ultraprecise clocks. Although comparisons at the full performance level of state-of-the-art optical clocks are possible on a continental scale [18,19] through a few specialized optical fiber links [20][21][22], intercontinental links are so far restricted to satellite-based methods that cannot fully exploit the clock performance [23]. A transfer standard enables world-wide interconnections between optical clocks and will thus benefit the efforts towards a redefinition of the SI second.Making laboratory setups compact and robust for transport is also the first step towards granting a wide community of users access to these devices [24][25][26]. Furthermore, transportability is a first step towards applications of optical clocks in space. Developments in these directions are ongoing for optical lattice clocks (OLCs) with strontium [27,28]; however, to our knowledge the single-ion clock reported recently [29] is the only other transportable clock with uncertainty below 10 −16 .The requirements on such a TOC are challenging indeed: To enable comparisons of other optical cl...

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Section: Pacs Numbersmentioning

confidence: 99%

Transportable Optical Lattice Clock with7×10−17Uncertainty

et al. 2017

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“…With a larger transponder bandwidth, this situation could be improved. The Atomic Clock Ensemble in Space (ACES) project [57], planned for the International Space Station after 2016, will make use of a microwave link that should lead to a fractional instability and inaccuracy of 3 × 10 −16 for a one-day measuring time. Optical links, either free space [58] or via optical telecommunication fibres [42], are even more promising.…”

Section: Comparisons Of Optical Clocks Remote From Each Othermentioning

confidence: 99%

Towards a redefinition of the second based on optical atomic clocks

Riehle

2015

Comptes Rendus. Physique

149

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Future redefinition of the second Frequency and time dissemination Mots-clés :Horloges optiques atomiques Étalons de fréquence Redéfinition future de la seconde Diffusion des fréquences et des signaux horairesThe rapid increase in accuracy and stability of optical atomic clocks compared to the caesium atomic clock as the primary standard of time and frequency asks for a future redefinition of the second in the International System of Units (SI). The status of the optical clocks based on either single ions in radio-frequency traps or on neutral atoms stored in an optical lattice is described, with special emphasis on the current work at the Physikalisch-Technische Bundesanstalt (PTB, Braunschweig, Germany). Besides the development and operation of different optical clocks with estimated fractional uncertainties in the 10 −18 range, the supporting work on ultra-stable lasers as core elements and the means to compare remote optical clocks with transportable standards, optical fibres, or frequency ratios is reported. Finally, the conditions, methods and next steps are discussed, which are the prerequisites for a future redefinition of the second. © 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.r é s u m é L'amélioration rapide en termes de précision et de stabilité des horloges atomiques optiques par rapport à l'horloge atomique au césium, qui constitue la référence primaire pour le temps et la fréquence, appelle une future redéfinition de la seconde dans le système international d'unités (SI). L'état d'avancement des horloges optiques basées sur des ions uniques dans des pièges radiofréquence ou sur des atomes neutres confinés dans le réseau optique est décrit, en insistant particulièrement sur le travail en cours à la PhysikalischTechnische Bundesanstalt (PTB, Brunswick, Allemagne). À côté du développement et de la mise en oeuvre de différentes horloges optiques avec des incertitudes fractionnelles estimées d'un ordre de grandeur de 10 −18 , les travaux sous-jacents sur les lasers ultra-stables comme éléments centraux ainsi que les moyens de comparer les horloges optiques lointaines avec des étalons transportables, des fibres optiques ou des rapports de fréquence * 507 sont exposés. Finalement, les conditions, les méthodes et les prochaines étapes sont discutées, qui sont des prérequis à une redéfinition de la seconde.

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“…A testament to the realizability of this system is the increasing number of OLC experiments popping up around the world, especially with the Strontium isotope which exhibits laser cooling and trapping wavelengths all accessible via diode lasers [22,26,27,28,29,30]. Perhaps unsurprisingly, the benefits imparted by using ever more stable laser local oscillators to interrogate the atoms make the state-of-the-art versions of these clocks very sensitive to thermal noise of both the cavity spacer and mirror coatings, and presently limits miniaturization of these systems.…”

Section: New Results From a Cryogenic Cs Fountain Clock At The Nationmentioning

confidence: 99%

Building a better atomic clock

Bloom¹

2013

Phys. Today

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DateThe final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. this work documents the first optical lattice clock to best all other atomic clock implementations, a mere 8 years after the first proof of principle experiments. In this thesis I will describe how we have overcome a number of important systematic uncertainties to achieve these results. This revolution in accuracy and precision opens the door for new experiments utilizing the clock as a probe of quantum many-body physics. To this end, a new apparatus has been designed that combines the unprecedented precision of clock experiments with the amazing progress attained in quantum gas experiments. DedicationTo my family, both old and new.

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Direct comparison of optical lattice clocks with an intercontinental baseline of 9000 km

Cited by 45 publications

References 22 publications

Transportable Optical Lattice Clock with7×10−17Uncertainty

Transportable Optical Lattice Clock with7×10−17Uncertainty

Towards a redefinition of the second based on optical atomic clocks

Building a better atomic clock

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