Quantum-logic-based 25 Mg + - 27 Al + optical frequency standard for the redefinition of the SI second

• DOI: 10.1103/physrevapplied.21.044017
• Publication Date: 2024-04-08T14:26:00Z
• Authors: Z. Y. Ma; K. Deng; Z. Y. Wang; W. Z. Wei; P. Hao; H. X. Zhang; L. R. Pang; B. Wang; F. F. Wu; H. L. Liu; W. H. Yuan; J. L. Chang; J. X. Zhang; Q. Y. Wu; J. Zhang; Z. H. Lu

Optical clocks have been demonstrated to be good choices redefine the SI ``second.'' With this goal, we constructed a quantum-logic-based ${}^{27}$$\mathrm{Al}$${}^{+}$ ion optical clock with fractional frequency uncertainty of $1.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}18}$. A ${}^{25}$$\mathrm{Mg}$${}^{+}$ is used as logic for sympathetic cooling, state readout, and frequency-shift measurement ion. The stability $2.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}/\sqrt{\ensuremath{\tau}}$, measured self-comparison method.