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 …

The transfer of high-quality time–frequency signals between remote locations underpins
many applications, including precision navigation and timing, clock-based geodesy, long …

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

Timescale comparison between optical atomic clocks over ground-to-space and terrestrial
free-space laser links will have enormous benefits for fundamental and applied sciences …

Quantum entanglement has been generated and verified in cold-atom experiments and
used to make atom-interferometric measurements below the shot-noise limit. However …

At present, there is a vast number of textbooks on Einstein's theory of gravity (general
relativity, GR) that are available for different kinds of readers and at different levels of …

Based on the second-order quantum interference between frequency entangled photons
that are generated by parametric down conversion, a quantum strategic algorithm for …

The dissemination of atomic clocks with fiber-based techniques finds application in the fields
of metrology, fundamental physics, navigation, and spectroscopy but is a challenge in terms …

We demonstrate carrier-phase optical two-way time-frequency transfer (carrier-phase
OTWTFT) through the two-way exchange of frequency comb pulses. Carrier-phase OTWTFT …