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Towards a redefinition of the second based on optical atomic clocks
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The 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.
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“Our work not only enables the above mentioned applications, but also clears the path towards a redefinition of the unit of time, the SI second2425 through regular and practical international comparisons of optical clocks.”
From A clock network for geodesy and fundamental science (2016) · cites this paper as [24]
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Metadata
- Authors
- Riehle, F.
- Corresponding author
- Riehle, Fritz
- ORCID
- Riehle, Fritz
- Venue
- Comptes Rendus. Physique
- Publisher
- MathDoc/Centre Mersenne
- Published
- 2015-06-01
- Volume
- 16
- Issue
- 5
- Pages
- 506-515
- ISSN
- 1631-0705 (ISSN-L)
- 1878-1535
- OpenAlex
- W1512386837
- Cited by
- 174
- References
- 65
- Citations by year
- 2026: 11 · 2025: 12 · 2024: 13 · 2023: 21 · 2022: 13 · 2021: 11 · 2020: 12 · 2019: 26 · 2018: 16 · 2017: 20 · 2016: 19
- FWCI
- 9.27
- Type
- journal article
- Language
- en
- Open access
- green
- arxiv.org
- Locations
- Comptes Rendus Physique (publishedVersion)
- arXiv (Cornell University) (submittedVersion)
- Physical Reports (submittedVersion)
- arXiv (Cornell University)
- Funders
- DFG (RTG 1729)
- Topics
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Advanced Frequency and Time Standards
- Physical Sciences › Physics and Astronomy › Instrumentation › Scientific Measurement and Uncertainty Evaluation
- Physical Sciences › Computer Science › Computer Networks and Communications › Network Time Synchronization Technologies
- Keywords
- redefinition of the second, optical atomic clocks, SI units, radio-frequency trap, optical lattice clock, neutral atoms, fractional frequency uncertainty, ultra-stable lasers, frequency transfer, frequency ratio, cesium atomic clock, time and frequency standards
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