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Displaying 1 - 12 of 12

Improved interspecies optical clock comparisons through differential spectroscopy

November 28, 2022
Author(s)
May E. Kim, Will McGrew, Nicholas Nardelli, Ethan Clements, Youssef Hassan, Xiaogang Zhang, Jose Valencia, Holly Leopardi, David Hume, Tara Fortier, Andrew Ludlow, David Leibrandt
Comparisons of high-accuracy optical atomic clocks \citeLudlow2015} are essential for precision tests of fundamental physics \citeSafronova2018}, relativistic geodesy \citeMcGrew2018, Grotti2018, Delva2019}, and the anticipated redefinition of the SI

Sub-recoil clock-transition laser cooling enabling shallow optical lattice clocks

September 8, 2022
Author(s)
Xiaogang Zhang, Kyle Beloy, Youssef Hassan, William McGrew, Chun-Chia Chen, Jacob Siegel, Tanner Grogan, Andrew Ludlow
Laser cooling is a key ingredient for quantum control of atomic systems in a variety of settings. In two-valence-electron atoms, two-stage Doppler cooling is typically used to bring atoms to the μK regime. Here, we implement a pulsed radial cooling scheme

Frequency Ratio Measurements with 18-Digit Accuracy Using a Network of Optical Clocks

March 24, 2021
Author(s)
Kyle Beloy, Martha I. Bodine, Tobias B. Bothwell, Samuel M. Brewer, Sarah L. Bromley, Jwo-Sy Chen, Jean-Daniel Deschenes, Scott Diddams, Robert J. Fasano, Tara Fortier, Youssef Hassan, David Hume, Dhruv Kedar, Colin J. Kennedy, Isaac Kader, Amanda Koepke, David Leibrandt, Holly Leopardi, Andrew Ludlow, Will McGrew, William Milner, Daniele Nicolodi, Eric Oelker, Tom Parker, John M. Robinson, Stefania Romisch, Stefan A. Schaeffer, Jeffrey Sherman, Laura Sinclair, Lindsay I. Sonderhouse, William C. Swann, Jian Yao, Jun Ye, Xiaogang Zhang
Atomic clocks occupy a unique position in measurement science, exhibiting higher accuracy than any other measurement standard and underpinning six out of seven base units in the SI system. By exploiting higher resonance frequencies, optical atomic clocks

Measurement of the 27Al+ and 87Sr absolute optical frequencies

January 21, 2021
Author(s)
Holly Leopardi, Kyle Beloy, Tobias B. Bothwell, Samuel M. Brewer, Sarah L. Bromley, Jwo-Sy Chen, Scott Diddams, Robert J. Fasano, Youssef S. Hassan, David B. Hume, Dhruv Kedar, Colin J. Kennedy, Isaac H. Khader, David R. Leibrandt, Andrew D. Ludlow, William F. McGrew, William R. Milner, Daniele Nicolodi, Eric Oelker, Thomas E. Parker, John M. Robinson, Stefania Romisch, Jeffrey A. Sherman, Lindsay I. Sonderhouse, William C. Swann, Jian Yao, Jun Ye, Xiaogang Zhang, Tara M. Fortier
We perform absolute measurement of the 27Al+ single-ion and 87Sr neutral lattice clock frequencies at the National Institute of Standards and Technology and JILA at the University of Colorado against a global ensemble of primary frequency standards. Over

Coherent Optical Clock Down-Conversion for Microwave Frequencies with 10-18 Instability

May 22, 2020
Author(s)
Takuma Nakamura, Josue Davila-Rodriguez, Holly Leopardi, Jeffrey Sherman, Tara Fortier, Xiaojun Xie, Joe C. Campbell, Will McGrew, Xiaogang Zhang, Youssef Hassan, Daniele Nicolodi, Kyle Beloy, Andrew Ludlow, Scott Diddams, Franklyn Quinlan
Optical atomic clocks are poised to redefine the SI second, thanks to stability and accuracy more than one hundred times better than the current microwave atomic clock standard. However, the best optical clocks have not seen their performance transferred

Modeling motional energy spectra and lattice light shifts in optical lattice clocks

May 8, 2020
Author(s)
Kyle Beloy, Will McGrew, Xiaogang Zhang, Daniele Nicolodi, Robert J. Fasano, Youssef Hassan, Roger Brown, Andrew Ludlow
We develop a model to describe the motional (i.e., external degree of freedom) energy spectra of atoms trapped in a one-dimensional optical lattice, taking into account both axial and radial confinement relative to the lattice axis. Our model respects the

Measurements of 25 Mg + and 27 Al + magnetic constants for improved ion clock accuracy

July 15, 2019
Author(s)
Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, Ethan Clements, Chin-wen Chou, Kyle Beloy, Will McGrew, Xiaogang Zhang, Robert J. Fasano, Daniele Nicolodi, Holly Leopardi, Tara Fortier, Scott Diddams, Andrew Ludlow, David J. Wineland, David Leibrandt, David Hume
We have measured the quadratic Zeeman coefficient for the 3P0 excited electronic state in 27Al+, C2=-71.944(24) MHz/T2 and the hyperfine constant of the 25Mg+ 2S1/2 ground electronic state, Ahfs = -596 254 250.981(45) Hz, with improved uncertainties. Both

Towards the optical second: verifying optical clocks at the SI limit

April 11, 2019
Author(s)
William F. McGrew, Xiaogang Zhang, Robert J. Fasano, Holly Leopardi, Daniele Nicolodi, Kyle P. Beloy, Jian Yao, Jeffrey A. Sherman, Stefan A. Schaeffer, Joshua J. Savory, Stefania Romisch, Christopher W. Oates, Thomas E. Parker, Tara M. Fortier, Andrew D. Ludlow
The pursuit of ever more precise measures of time and frequency motivates redefinition of the second in terms of an optical atomic transition. To ensure continuity with the current definition, based on the microwave hyperfine transition in 133 Cs, it is

First observation with global network of optical atomic clocks aimed for a dark matter detection

January 30, 2019
Author(s)
P. Wcislo, P. Ablewski, Kyle Beloy, S. Bilicki, M. Bober, Roger Brown, Robert J. Fasano, R. Ciurylo, H. Hachisu, T. Ido, J. Lodewyck, Andrew Ludlow, Will McGrew, P. Morzynski, Daniele Nicolodi, Marco Schioppo, M. Sekido, R. Le Targat, P. Wolf, Xiaogang Zhang, B. Zjawin, M. Zawada
We report on the first earth-scale quantum sensor network based on optical atomic clocks aimed at dark matter (DM) detection. Exploiting differences in the susceptibilities to the fine- structure constant of essential parts of an optical atomic clock, i.e

Atomic clock performance beyond Earth’s gravitational limit

December 6, 2018
Author(s)
William F. McGrew, Xiaogang Zhang, Robert J. Fasano, Stefan A. Schaeffer, Kyle P. Beloy, Daniele Nicolodi, Roger C. Brown, N. Hinkley, G. Milani, Marco Schioppo, T. H. Yoon, Andrew D. Ludlow
The passage of time is tracked by counting oscillations of a suitable frequency reference (e.g., the number of revolutions of Earth around the sun or the number of swings of a pendulum of a grandfather clock). By referencing the oscillations arising from

A Faraday-shielded, DC Stark-free optical lattice clock

May 2, 2018
Author(s)
Kyle P. Beloy, Xiaogang Zhang, William F. McGrew, Nathan M. Hinkley, Tai H. Yoon, Daniele Nicolodi, Robert J. Fasano, Stefan A. Schaeffer, Roger C. Brown, Andrew D. Ludlow
We demonstrate the absence of a DC Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed

Hyperpolarizability and Operational Magic Wavelength in an Optical Lattice Clock

December 19, 2017
Author(s)
Roger C. Brown, Nate B. Phillips, Kyle P. Beloy, William F. McGrew, Marco Schioppo, Robert J. Fasano, Gianmaria Milani, Xiaogang Zhang, Nathan M. Hinkley, Holly F. Leopardi, T H. Yoon, Daniele Nicolodi, Tara M. Fortier, Andrew D. Ludlow
Optical clocks benefit from tight atomic confinement enabling extended interrogation times as well as Doppler- and recoil-free operation. However, these benefits come at the cost of frequency shifts that, if not properly controlled, may degrade clock