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40Ca+ optical clocks in China
- Source :
- AVS Quantum Science. 3:044701
- Publication Year :
- 2021
- Publisher :
- American Vacuum Society, 2021.
-
Abstract
- In this review, the improvements made in the past two decades for 40Ca+ optical clocks in China are presented. Uncertainty of below 1.3×10−17 was achieved by applying the “magic” RF trapping frequency and introducing a generalized Ramsey excitation scheme. The stability of 40Ca+ optical clocks has been improved to 2.5×10−15/τ with an uptime rate of 93.8% by implementing two ameliorated lock algorithms in the Ramsey excitation scheme. A long-term clock frequency comparison shows a clock stability of 6.3 × 10−18 in an averaging time of 524 000 s. A robust and transportable clock installed in an air-conditioned car trailer can achieve almost the same performance of laboratory clocks. A height difference between transportable and laboratory clocks was measured with an uncertainty of 0.33 m and the absolute frequency of 40Ca+ optical clock transitions was remeasured as 411 042 129 776 400.41(23) Hz, with a fractional uncertainty of 5.6×10−16 based on a Cs fountain clock in the National Institute of Metrology after the transportable clock was transported from Wuhan to Beijing. The author predicts that transportable single-ion optical clocks especially based on the 40Ca+ will make a significant contribution to the construction of a world-wide optical clock network and the redefinition of the unit of time in the future.
- Subjects :
- Physics
Record locking
Computer Networks and Communications
business.industry
Absolute frequency
Clock rate
Electrical engineering
Height difference
Condensed Matter Physics
Stability (probability)
Atomic and Molecular Physics, and Optics
Electronic, Optical and Magnetic Materials
Metrology
Computational Theory and Mathematics
Optical clock
Electrical and Electronic Engineering
Physical and Theoretical Chemistry
business
Subjects
Details
- ISSN :
- 26390213
- Volume :
- 3
- Database :
- OpenAIRE
- Journal :
- AVS Quantum Science
- Accession number :
- edsair.doi...........f519c8daef2043d42f063168b9d85608