Optical atomic clocks represent the state of the art in the frontier of modern measurement
science. In this article a detailed review on the development of optical atomic clocks that are …

We review experimental progress on optical atomic clocks and frequency transfer, and
consider the prospects of using these technologies for geodetic measurements. Today …

We search for ultralight scalar dark matter candidates that induce oscillations of the fine
structure constant, the electron and quark masses, and the quantum chromodynamics …

Optical atomic clocks, due to their unprecedented stability,–and uncertainty,,–, are already
being used to test physical theories, and herald a revision of the International System of …

The accuracy of atomic clocks relies on the superb reproducibility of atomic spectroscopy,
which is accomplished by careful control and the elimination of environmental perturbations …

Atomic clocks have been instrumental in science and technology, leading to innovations
such as global positioning, advanced communications, and tests of fundamental constant …

To compare the increasing number of optical frequency standards, highly stable optical
signals have to be transferred over continental distances. We demonstrate optical-frequency …

Transition frequencies of atoms and ions are among the most accurately accessible
quantities in nature, playing important roles in pushing the frontiers of science by testing …

Progress in realizing the SI second had multiple technological impacts and enabled further
constraint of theoretical models in fundamental physics. Caesium microwave fountains …

We experimentally investigate an optical frequency standard based on the 467 nm (642
THz) electric-octupole reference transition S 1/2 2 (F= 0)→ F 7/2 2 (F= 3) in a single trapped …