Atomic clock performance beyond the geodetic limit

作     者：McGrew, W.F. Zhang, X. Fasano, R.J. Schaffer, S.A. Beloy, K. Nicolodi, D. Brown, R.C. Hinkley, N. Milani, G. Schioppo, M. Yoon, T.H. Ludlow, A.D. 

作者机构：National Institute of Standards and Technology 325 Broadway BoulderCO80305 United States Department of Physics University of Colorado BoulderCO80309 United States State Key Laboratory of Advanced Optical Communication Systems and Networks Institute of Quantum Electronics School of Electronics Engineering and Computer Science Peking University Beijing100871 China Niels Bohr Institute University of Copenhagen Blegdamsvej 17 Copenhagen2100 Denmark Georgia Tech Research Institute AtlantaGA30332 United States Stable Laser Systems BoulderCO80301 United States Istituto Nazionale di Ricerca Metrologica Strada delle Cacce 91 Torino10135 Italy Politecnico di Torino Corso duca degli Abruzzi 24 Torino10125 Italy  TeddingtonTW110LW United Kingdom Department of Physics Korea University 145 Anam-ro Seongbuk-gu Seoul02841 Korea Republic of 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2018年

核心收录：

主　　题：Earth (planet) 

摘      要：The passage of time is tracked by counting oscillations of a frequency reference, such as Earth s revolutions or swings of a pendulum. By referencing atomic transitions, frequency (and thus time) can be measured more precisely than any other physical quantity, with the current generation of optical atomic clocks reporting fractional performance below the 10-17level1-5. However, the theory of relativity prescribes that the passage of time is not absolute, but impacted by an observer s reference frame. Consequently, clock measurements exhibit sensitivity to relative velocity, acceleration and gravity potential. Here we demonstrate optical clock measurements surpassing the present-day ability to account for the gravitational distortion of space-time across the surface of Earth. In two independent ytterbium optical lattice clocks, we demonstrate unprecedented levels in three fundamental benchmarks of clock performance. In units of the clock frequency, we report systematic uncertainty of 1.4 × 10-18, measurement instability of 3.2 × 10-19and reproducibility characterised by ten blinded frequency comparisons, yielding a frequency difference of [-7±(5)stat±(8)sys] × 10-19. While differential sensitivity to gravity could degrade the performance of these optical clocks as terrestrial standards of time, this same sensitivity can be used as an exquisite probe of geopotential5-9. Near the surface of Earth, clock comparisons at the 1 × 10-18 level provide 1 cm resolution along gravity, outperforming state-of-the-art geodetic techniques. These optical clocks can further be used to explore geophysical phenomena10, detect gravitational waves11, test general relativity12 and search for dark matter. Copyright © 2018, The Authors. All rights reserved.