Direct comparison of two spin-squeezed optical clock ensembles at the 10−17 level

JM Robinson, M Miklos, YM Tso, CJ Kennedy… - Nature Physics, 2024 - nature.com
Building scalable quantum systems that demonstrate performance enhancement based on
entanglement is a major goal in quantum computing and metrology. The main challenge …

Free-space dissemination of time and frequency with 10−19 instability over 113 km

Q Shen, JY Guan, JG Ren, T Zeng, L Hou, M Li, Y Cao… - Nature, 2022 - nature.com
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 …

Improved limits for violations of local position invariance from atomic clock comparisons

R Lange, N Huntemann, JM Rahm, C Sanner… - Physical Review Letters, 2021 - APS
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 …

Prospects and challenges for squeezing-enhanced optical atomic clocks

M Schulte, C Lisdat, PO Schmidt, U Sterr… - Nature …, 2020 - nature.com
Optical atomic clocks are a driving force for precision measurements due to the high
accuracy and stability demonstrated in recent years. While further improvements to the …

Search for ultralight dark matter from long-term frequency comparisons of optical and microwave atomic clocks

T Kobayashi, A Takamizawa, D Akamatsu… - Physical Review Letters, 2022 - APS
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 …

Comparing ultrastable lasers at 7 × 10−17 fractional frequency instability through a 2220 km optical fibre network

M Schioppo, J Kronjaeger, A Silva, R Ilieva… - Nature …, 2022 - nature.com
Ultrastable lasers are essential tools in optical frequency metrology enabling unprecedented
measurement precision that impacts on fields such as atomic timekee**, tests of …

New horizons: Scalar and vector ultralight dark matter

D Antypas, A Banerjee, C Bartram… - arxiv preprint arxiv …, 2022 - arxiv.org
The last decade has seen unprecedented effort in dark matter model building at all mass
scales coupled with the design of numerous new detection strategies. Transformative …

Testing gravity with cold atom interferometry: results and prospects

GM Tino - Quantum Science and Technology, 2021 - iopscience.iop.org
Atom interferometers have been developed in the last three decades as new powerful tools
to investigate gravity. They were used for measuring the gravity acceleration, the gravity …

Nuclear clocks for testing fundamental physics

E Peik, T Schumm, MS Safronova… - Quantum Science …, 2021 - iopscience.iop.org
The low-energy, long-lived isomer in 229 Th, first studied in the 1970s as an exotic feature in
nuclear physics, continues to inspire a multidisciplinary community of physicists. It has …

Search for topological defect dark matter with a global network of optical magnetometers

S Afach, BC Buchler, D Budker, C Dailey… - Nature Physics, 2021 - nature.com
Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can
form stable, macroscopic field configurations in the form of topological defects that could …