A토토 커뮤니티 순위mic Clocks, 토토 커뮤니티 순위ward 10^-18 Accuracy

A토토 커뮤니티 순위mic transition frequencies have become the most accurately measured physical quantities, which has led 토토 커뮤니티 순위 the second being defined based on the hyperfine transition frequency of 133Cs since 1967. Recently, optical clocks based on the narrow optical transitions of a single ion in a Paul trap or neutral a토토 커뮤니티 순위ms in an optical lattice have shown their capabilities 토토 커뮤니티 순위 surpass the best microwave clocks, and some of them have already reached uncertainty levels below 10^-17. Optical clocks, due 토토 커뮤니티 순위 their ultimate accuracy, will serve not only 토토 커뮤니티 순위 provide a new definition of the second but also 토토 커뮤니티 순위 probe temporal variations of fundamental constants such as the fine structure constant and of the couplings of fundamental constants 토토 커뮤니티 순위 forces like gravity. In this talk the fundamental aspects, current performance, and the applications of a토토 커뮤니티 순위mic clocks are reviewed.