Quantum theory has been successfully validated in numerous laboratory experiments. But
would such a theory, which effectively describes the behavior of microscopic physical …

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

Atomic clocks are vital in a wide array of technologies and experiments, including tests of
fundamental physics. Clocks operating at optical frequencies have now demonstrated …

Microwave photonic technologies, which upshift the carrier into the optical domain, have
facilitated the generation and processing of ultra-wideband electronic signals at vastly …

Optical atomic clocks require local oscillators with exceptional optical coherence owing to
the challenge of performing spectroscopy on their ultranarrow-linewidth clock transitions …

Laboratory optical atomic clocks achieve remarkable accuracy (now counted to 18 digits or
more), opening possibilities for exploring fundamental physics and enabling new …

State-of-the-art atomic clocks are based on the precise detection of the energy difference
between two atomic levels, which is measured in terms of the quantum phase accumulated …

A list of standard reference frequency values (LoF) of quantum transitions from the
microwave to the optical regime has been recommended by the International Committee for …

Microwave photonics offers transformative capabilities for ultra-wideband electronic signal
processing and frequency synthesis with record-low phase noise levels. Despite the intrinsic …

One goal of the second quantum revolution is developing an approach to transmit coherent
quantum information across the world, forming the basis of the quantum Internet. Achieving …