With the establishment and maturation of the experimental programs searching for new
physics with sizeable couplings at the LHC, there is an increasing interest in the broader …

This article reviews recent developments in tests of fundamental physics using atoms and
molecules, including the subjects of parity violation, searches for permanent electric dipole …

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 …

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

We experimentally investigate an optical frequency standard based on the S 1/2 2 (F= 0)→ F
7/2 2 (F= 3) electric octupole (E 3) transition of a single trapped Yb+ 171 ion. For 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 present improved constraints on the coupling of ultralight bosonic dark matter to photons
based on long-term measurements of two optical frequency ratios. In these optical clock …

A new class of solutions to the electroweak hierarchy problem is presented that does not
require either weak-scale dynamics or anthropics. Dynamical evolution during the early …

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

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 …