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Uncertainty evaluation of an 171Yb optical lattice clock at NMIJ
摘要： We report an uncertainty evaluation of an 171Yb optical lattice clock with a total fractional uncertainty of 3.6 × 10^{-16}, which is mainly limited by the lattice-induced light shift and the blackbody radiation shift. Our evaluation of the lattice-induced light shift, the density shift, and the second-order Zeeman shift is based on an interleaved measurement where we measure the frequency shift using the alternating stabilization of a clock laser to the 6s2 1S0–6s6p 3P0 clock transition with two different experimental parameters. In the present evaluation, the uncertainties of two sensitivity coefficients for the lattice-induced hyperpolarizability shift d incorporated in a widely used light shift model by RIKEN and the second-order Zeeman shift aZ are improved compared with the uncertainties of previous coefficients. The hyperpolarizability coefficient d is determined by investigating the trap potential depth and the light shifts at the lattice frequencies near the two-photon transitions 6s6p3P0–6s8p3P0, 6s8p3P2, and 6s5f3F2. The obtained values are d = ?1.1(4) μHz and aZ = ?6.6(3) Hz/mT2. These improved coefficients should reduce the total systematic uncertainties of Yb lattice clocks at other institutes.
关键词： precise measurement,optical lattice clock,optical frequency comb,Frequency standards,SI second
更新于2025-09-23 15:23:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Measurement of Molecular Transition Frequencies with the Uncertainties Lower Than 10 <sup>?17</sup>
摘要： Precise measurement of atomic transition frequencies (neutral, ion) have been performed and the uncertainty of the order of 10-18 has been attained with several transitions. However, the measurement uncertainty lower than 10-15 has never been attained with molecular transition frequencies. Precise measurement of molecular transition frequencies are useful to develop physics beyond the standard model: detection of electron electric dipole moment, detection of symmetry violation between optical isomers of chiral molecules, and search for the variation in the proton-to-electron mass ratio etc.. The attained systematic frequency is limited by the Stark, Zeeman, and electric quadrupole shifts, which have significant dependence on the electronic states and the angular momentum quantum numbers (electron orbital angular momentum, spin, nuclear spin, molecular rotation, and couplings between them). The molecular pure vibrational transition frequencies without changing any angular momentum quantum numbers are expected to be advantageous for precise measurement, because all frequency shifts at upper and lower states are more than 99 % canceled. Theoretical estimation of attainable accuracies will be given in this presentation.
关键词： electric quadrupole shift,precise measurement,uncertainty,Zeeman shift,Stark shift,molecular transition frequencies
更新于2025-09-12 10:27:22
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Precision Measurement of Magnetic Field Based on Second-Order Sideband Generation in a Hybrid Electromagnetic-Optomechanical System
摘要： Realizing the precise measurement of the magnetic field is of great significance in many fields, including optics, metrology, bioscience, and engineering technology. With the development of nanophotonics, optomechanical systems have provided an on-chip platform to explore new availability for high-sensitivity measurement due to its extreme sensitivity on weak force [Ref. Nat. Nanotechnol. 7, 509 (2012)]. In this paper, a theoretical scheme for precision measurement of magnetic field based on a nonlinear optomechanical effect: second-order sideband generation in a hybrid electromagnetic-optomechanical system is proposed. We find that the system exhibits a kenspeckle magnetic-field-dependent generation of the frequency component at the second-order sideband, which is more sensitive than the previous paper based on optomechanically induced transparency. Numerical calculations show that the measurement accuracy of the magnetic field in our scheme may reach the order of nT or even smaller, so our findings will provide a more accurate solution for the precise measurement of magnetic fields.
关键词： second-order sideband generation,Precise measurement,cavity optomechanics,magnetic field
更新于2025-09-09 09:28:46