[1] [1] Takamoto M, Hong F L, Higashi R, et al. An optical lattice clock［J］. Nature, 2005,435(7040): 321-324. DOI: 10.1038/nature03541.

[2] [2] Bloom B J, Nicholson T L, Williams J R, et al. An optical lattice clock with accuracy and stability at the 10－18 level［J］. Nature, 2014, 506(7486): 71-75. DOI: 10.1038/nature12941.

[3] [3] Nicholson T L, Campbell S L, Hutson R B, et al. Systematic evaluation of an atomic clock at 2×1018 total uncertainty［J］. Nature Communications, 2015, 6: 6896. DOI: 10.1038/ncomms7896.

[4] [4] Huntemann N, Sanner C, Lipphardt B, et al. Single-Ion Atomic Clock with 3×10－18 Systematic Uncertainty［J］. Physical Review Letters, 2016, 116(6): 063001. DOI: 10.1103/PhysRevLett.116.063001.

[5] [5] Riehle F, Gill P, Arias F, et al. The CIPM list of recommended frequency standard values: guidelines and procedures［J］. Metrologia, 2018, 55(2): 188-200. DOI: 10.1088/1681-7575/aaa302.

[6] [6] Mcgrew W F, Zhang X, Fasano R J, et al. Atomic clock performance enabling geodesy below the centimetre level［J］. Nature, 2018, 564(7734): 87. DOI: 10.1038/s41586-018-0738-2.

[7] [7] Brewer S M, Chen J S, Hankin A M , et al. 27Al+ Quantum-Logic Clock with a Systematic Uncertainty below 10－18［J］. Physical Review Letters, 2019, 123(3): 033201. DOI: 10.1103/PhysRevLett.123.033201.

[8] [8] Oelker E, Hutson R B, Kennedy C J, et al. Demonstration of 4.8×10－17 stability at 1s for two independent optical clocks［J］. Nature Photonics, 2019, 13(10): 714-719. DOI: 10.1038/s41566-019-0493-4.

[9] [9] Derevianko A, Pospelov M. Hunting for topological dark matter with atomic clocks［J］. Nature Physics, 2014, 10(12): 933-936. DOI:10.1038/nphys3137.

[10] [10] Wciso P, Morzyński P, Bober M, et al. Experimental constraint on dark matter detection with optical atomic clocks［J］. Nature Astronomy, 2018, 1(1): 0009. DOI: 10.1038/s41550-016-0009.

[11] [11] Wciso P, Ablewski P, Beloy K, et al. New bounds on dark matter coupling from a global network of optical atomic clocks［J］. Science Advances, 2018, 4(12): 4869. DOI: 10.1126/sciadv.aau4869.

[12] [12] Hachisu H, Nakagawa F, Hanado Y, et al. Months-long real-time generation of a time scale based on an optical clock［J］. Scientific Reports, 2018, 8(1): 1-12. DOI: 10.1038/s41598-018-22423-5.

[13] [13] Yao J, Sherman J A, Fortier T, et al. Optical-Clock-Based Time Scale［J］. Physical Review Applied, 2019, 12(4): 044069. DOI: 10.1103/PhysRevApplied.12.044069.

[14] [14] Delva P, Puchades N, Schoenemann E, et al. Gravitational Redshift Test Using Eccentric Galileo Satellites［J］. Physical Review Letters, 2018, 121(23): 231101. DOI: 10.1103/PhysRevLett.121.231101.

[15] [15] Herrmann S, Finke F, Lülf M, et al. Test of the gravitational redshift with Galileo satellites in an eccentric orbit［J］. Physical Review Letters, 2018, 121(23): 231102. DOI: 10.1103/PhysRevLett.121.231102.

[16] [16] Takamoto M, Ushijima I, Ohmae N, et al. Test of general relativity by a pair of transportable optical lattice clocks［J］. Nature Photonics, 2020, 14(7): 1-5. DOI: 10.1038/s41566-020-0619-8.

[17] [17] Takano T, Takamoto M, Ushijima I, et al. Geopotential measurements with synchronously linked optical lattice clocks［J］. Nature Photonics, 2016, 10(10): 662-666. DOI:10.1038/nphoton.2016.159.

[18] [18] Lui H, Zhang X, Jiang K L, et al. Realization of Closed-Loop Operation of Optical Lattice Clock Based on 177Yb［J］. Chin Phys Lett, 2017, 34(2): 24-27. DOI: 10.1088/0256-307X/34/2/020601.