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

Particle physics today faces the challenge of explaining the mystery of dark matter, the origin
of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent …

WDs and neutron stars are far-reaching and multi-faceted laboratories in the hunt for dark
matter. We review detection prospects of wave-like, particulate, macroscopic and black hole …

The passage of time is tracked by counting oscillations of a frequency reference, such as
Earth's revolutions or swings of a pendulum. By referencing atomic transitions, frequency …

Concerted efforts are underway to establish an infrastructure for a global quantum Internet to
realise a spectrum of quantum technologies. This will enable more precise sensors, secure …

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

Networks of optical clocks find applications in precise navigation,, in efforts to redefine the
fundamental unit of the 'second',,–and in gravitational tests. As the frequency instability for …

Rapid progress in optical atomic clock performance has advanced the frontiers of
timekee**, metrology and quantum science,–. Despite considerable efforts, the …

A clock at a higher altitude ticks faster than one at a lower altitude, in accordance with
Einstein's theory of general relativity. The outstanding stability and accuracy of optical …

We conduct frequency comparisons between a state-of-the-art strontium optical lattice clock,
a cryogenic crystalline silicon cavity, and a hydrogen maser to set new bounds on the …