BACKGROUND The generation and control of coherent electromagnetic waves, such as
those provided by electronic oscillators in the radio frequency domain or lasers in the optical …

Quantum networks providing shared entanglement over a mesh of quantum nodes will
revolutionize the field of quantum information science by offering novel applications in …

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 …

We outline the experimental concept and key scientific capabilities of AION (Atom
Interferometer Observatory and Network), a proposed experimental programme using cold …

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 …

Linear quantum measurements with independent particles are bounded by the standard
quantum limit, which limits the precision achievable in estimating unknown phase …

Quantum sensors are used for precision timekee**, field sensing and quantum
communication,–. Comparisons among a distributed network of these sensors are capable …

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 …