Measurement of collision frequency shift in strontium optical lattice clock

doi:10.7498/aps.68.20191147

	Measurement of collision frequency shift in strontium optical lattice clock
	Lu Xiao-Tong 1,2; Li Ting 1,2; Kong De-Huan 1,2; Wang Ye-Bing 1,2; Chang Hong 1,2
刊名	ACTA PHYSICA SINICA
	2019-12-05
卷号	68 期号:23 页码:6
关键词	collision frequency shift strontium optical lattice clock optical lattice spin-polarized spectrum
ISSN号	1000-3290
DOI	10.7498/aps.68.20191147
英文摘要	In a one-dimensional Fermion optical lattice clock, the p-wave scattering can occur when collision energy is sufficient to overcome the centrifugal barrier of p-wave scattering. According to Pauli exclusion principle, the s-wave scattering is forbidden between two identical Fermions. However, the s-wave scattering may also exist due to inhomogeneous excitation which leads to some difference between two Fermions. In terms of the uncertainty evaluation of a neutral atomic optical lattice clock, the frequency correction and uncertainty caused by atomic interaction cannot be ignored, and it will affect the evaluation of AC stark frequency shift. So the uncertainty evaluation of the collision frequency shift should be as small as possible. Only in this way can a neutral atomic optical lattice clock have a state-of-the-art performance. The collision frequency shift originates from the interaction between atoms trapped in an identical lattice. In this study, the collision frequency shift of Sr-87 optical lattice clock at the National Timing Service Center is measured experimentally. A horizontal one-dimensional optical lattice is constructed. The number of tapped atoms is about 104 at a temperature of 3.4 mu K. A laser is used to pump the atoms to either of the Zeeman energy levels of m(F) = +/- 9/2 in the ground state, and the clock transition spin polarization spectrum is obtained. In a spin polarized Fermions system, the collision frequency shift relating to atomic density is measured by the method of self-comparison. The method of self-comparison, which takes full advantage of the excellent short-term stability of the clock laser, can be used to measure the frequency difference caused by the variety of system parameters. Owing to the fact that the collision frequency shift is proportional to atomic density, the collision frequency shift can be measured by the method of self-comparison between high and low atomic density. In the experiment, the systematic state is changed between high and low atomic density by periodically changing the loading time of the first stage of cooling. In order to reduce the statistical uncertainty of the measurement, the collision frequency shift is separately measured 37 times. Finally, when the atomic density is 4 x 10(10)/cm(3), the collision frequency shift is -0.13 Hz, and the statistical uncertainty of the measurement is 3.1 x 10(-17). The Allan deviation of self-comparison between low and high atomic density reaches 4 x 10(-17) after 8000 s averaging time, indicating that the accuracy of the measurement is reliable and on the order of 10(-17). This work lays a foundation of the total uncertainty evaluation of Sr-87 optical lattice clock.
资助项目	National Natural Science Foundation of China[11803042] ; National Natural Science Foundation of China[11474282] ; National Natural Science Foundation of China[61775220] ; National Key Research and Development Program of China[2016YFF0200201] ; Chinese Academy of Sciences[XDB21030100] ; Chinese Academy of Sciences[QYZDB-SSW-JSC004] ; Youth Innovation Promotion Association the Chinese Academy of Sciences[2019400]
WOS研究方向	Physics
语种	英语
出版者	CHINESE PHYSICAL SOC
WOS记录号	WOS:000501344000010
资助机构	National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key Research and Development Program of China ; National Key Research and Development Program of China ; Chinese Academy of Sciences ; Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences ; Youth Innovation Promotion Association the Chinese Academy of Sciences
内容类型	期刊论文
源URL	[http://210.72.145.45/handle/361003/12015]
专题	中国科学院国家授时中心
通讯作者	Wang Ye-Bing; Chang Hong
作者单位	1.Natl Time Serv Ctr, CAS Key Lab Time & Frequency Primary Stand, Xian 710600, Shaanxi, Peoples R China 2.Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Lu Xiao-Tong,Li Ting,Kong De-Huan,et al. Measurement of collision frequency shift in strontium optical lattice clock[J]. ACTA PHYSICA SINICA,2019,68(23):6.
APA	Lu Xiao-Tong,Li Ting,Kong De-Huan,Wang Ye-Bing,&Chang Hong.(2019).Measurement of collision frequency shift in strontium optical lattice clock.ACTA PHYSICA SINICA,68(23),6.
MLA	Lu Xiao-Tong,et al."Measurement of collision frequency shift in strontium optical lattice clock".ACTA PHYSICA SINICA 68.23(2019):6.