Quantum sensing and metrology use coherent superposition states of quantum systems to
detect and measure physical effects of interest. Their sensitivity is typically limited by the …

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 …

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 …

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 …

Optical frequency combs were developed nearly two decades ago to support the world's
most precise atomic clocks. Acting as precision optical synthesizers, frequency combs …

We describe an optical atomic clock based on quantum-logic spectroscopy of the S 0 1↔ P
3 0 transition in Al+ 27 with a systematic uncertainty of 9.4× 10-19 and a frequency stability …

This paper outlines the roadmap towards the redefinition of the second, which was recently
updated by the CCTF Task Force created by the CCTF in 2020. The main achievements of …

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 …

Deployed optical clocks will improve positioning for navigational autonomy, provide remote
time standards for geophysical monitoring and distributed coherent sensing, allow time …

We compare two optical clocks based on the S 2 1/2 (F= 0)→ D 2 3/2 (F= 2) electric
quadrupole (E2) and the S 2 1/2 (F= 0)→ F 2 7/2 (F= 3) electric octupole (E3) transition of Yb …