231 citations · 685 across the 20 of their papers we have counts for
20 papers
International comparison of optical frequencies with transportable optical lattice clocks
International Clock, Oscillator Networking, Collaboration +37
Optical clocks have improved their frequency stability and estimated accuracy by more than two orders of magnitude over the best caesium microwave clocks that realise the SI second…
Analysis of atomic-clock data to constrain variations of fundamental constants
Nathaniel Sherrill, Adam O. Parsons, Charles F. A. Baynham +13
We present a new framework to study the time variation of fundamental constants in a model-independent way. Model independence implies more free parameters than assumed in previous…
Frequency stability and phase noise measurements of a 5,860 km-long intercontinental seafloor optical fibre cable
Giuseppe Marra, Paul Gaynor, Mattia Cantono +8
Optical clock comparison via optical fibre links has been achieved over continental scales, but has not yet been demonstrated intercontinentally. The transfer of ultra-stable optic…
Measuring the stability of fundamental constants with a network of clocks
G. Barontini, L. Blackburn, V. Boyer +41
The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark m…
QSNET, a network of clocks for measuring the stability of fundamental constants
G. Barontini, V. Boyer, X. Calmet +19
The QSNET consortium is building a UK network of next-generation atomic and molecular clocks that will achieve unprecedented sensitivity in testing variations of the fine structure…
Improving the Q factor of an optical atomic clock using quantum non-demolition measurement
William Bowden, Alvise Vianello, Ian R Hill +2
Quantum non-demolition (QND) measurement is a remarkable tool for the manipulation of quantum systems. It allows specific information to be extracted while still preserving fragile…
A strontium optical lattice clock with uncertainty and measurement of its absolute frequency
Richard Hobson, William Bowden, Alissa Silva +5
We present a measurement of the absolute frequency of the 5s S to 5s5p P transition in Sr, which is a secondary representation of the SI second. We descr…
A mid-infrared magneto-optical trap of metastable strontium for an optical lattice clock
Richard Hobson, William Bowden, Alvise Vianello +2
We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92 m transition between the energy levels and $5s4…
Cavity-enhanced non-destructive detection of atoms for an optical lattice clock
Richard Hobson, William Bowden, Alvise Vianello +2
We demonstrate a new method of cavity-enhanced non-destructive detection of atoms for a strontium optical lattice clock. The detection scheme is shown to be linear in atom number u…
Direct comparisons of European primary and secondary frequency standards via satellite techniques
F. Riedel, A. Al-Masoudi, E. Benkler +46
We carried out a 26-day comparison of five simultaneously operated optical clocks and six atomic fountain clocks located at INRIM, LNE-SYRTE, NPL and PTB by using two satellite-bas…
A pyramid MOT with integrated optical cavities as a cold atom platform for an optical lattice clock
William Bowden, Richard Hobson, Ian R. Hill +6
We realize a two-stage, hexagonal pyramid magneto-optical trap (MOT) with strontium, and demonstrate loading of cold atoms into cavity-enhanced 1D and 2D optical lattice traps, all…
Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks
B. M. Roberts, P. Delva, A. Al-Masoudi +51
We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in…
Guidelines for developing optical clocks with fractional frequency uncertainty
Moustafa Abdel-Hafiz, Piotr Ablewski, Ali Al-Masoudi +42
There has been tremendous progress in the performance of optical frequency standards since the first proposals to carry out precision spectroscopy on trapped, single ions in the 19…
Rydberg Electrometry for Optical Lattice Clocks
William Bowden, Richard Hobson, Paul Huillery +3
Electrometry is performed using Rydberg states to evaluate the quadratic Stark shift of the clock transition in strontium. By measurin…
Test of special relativity using a fiber network of optical clocks
P. Delva, J. Lodewyck, S. Bilicki +28
Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching…
Development of a strontium optical lattice clock for the SOC mission on the ISS
S. Origlia, S. Schiller, M. S. Pramod +25
The ESA mission "Space Optical Clock" project aims at operating an optical lattice clock on the ISS in approximately 2023. The scientific goals of the mission are to perform tests…
A low maintenance Sr optical lattice clock
Ian R. Hill, Richard Hobson, William Bowden +4
We describe the Sr optical lattice clock apparatus at NPL with particular emphasis on techniques used to increase reliability and minimise the human requirement in its operation. C…
Modified hyper-Ramsey methods for the elimination of probe shifts in optical clocks
R. Hobson, W. Bowden, S. A. King +3
We develop a method of modified hyper-Ramsey spectroscopy in optical clocks, achieving complete immunity to the frequency shifts induced by the probing fields themselves. Using par…
Development of a strontium optical lattice clock for the SOC mission on the ISS
K. Bongs, Y. Singh, L. Smith +24
Ultra-precise optical clocks in space will allow new studies in fundamental physics and astronomy. Within an European Space Agency (ESA) program, the Space Optical Clocks (SOC) pro…
Zeeman Slowers for Strontium based on Permanent Magnets
Ian R. Hill, Yuri B. Ovchinnikov, Elizabeth M. Bridge +2
We present the design, construction, and characterisation of longitudinal- and transverse-field Zeeman slowers, based on arrays of permanent magnets, for slowing thermal beams of a…