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Search Publications by: David Leibrandt (Assoc)

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Displaying 1 - 23 of 23

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

Lifetime-Limited Interrogation of Two Independent 27Al+ Clocks using Correlation Spectroscopy

December 9, 2020
Author(s)
Ethan Clements, May E. Kim, Kaifeng Cui, Aaron M. Hankin, Samuel M. Brewer, Jose Valencia, Jwo-Sy Chen, Chin-wen Chou, David Leibrandt, David Hume
Laser decoherence limits the stability of optical clocks by broadening the observable resonance linewidths and adding noise during the dead time between clock probes. Correlation spectroscopy avoids these limitations by measuring correlated atomic

Quantum entanglement between an atom and a molecule

May 20, 2020
Author(s)
Yiheng Lin, David Leibrandt, Dietrich Leibfried, Chin-wen Chou
Expanding quantum control to a broad range of physical systems paves the way for advances in various aspects of science and technology, such as stringent tests of fundamental physics, quantum-enhanced sensors, and quantum information processing

Frequency-comb spectroscopy on pure quantum states of a single molecular ion

March 27, 2020
Author(s)
Chin-wen Chou, Alejandra L. Collopy, Christoph Kurz, Yiheng Lin, Michael E. Harding, Philipp N. Plessow, Tara M. Fortier, Scott A. Diddams, Dietrich G. Leibfried, David R. Leibrandt
Spectroscopy is a powerful tool for studying molecular properties and is commonly performed on large thermal ensembles of molecules that are perturbed by motional shifts and interactions with the environment and one another, resulting in convoluted spectra

Systematic uncertainty due to background-gas collisions in trapped-ion optical clocks

September 30, 2019
Author(s)
Aaron M. Hankin, Ethan Clements, Huang Yao, Samuel M. Brewer, Jwo-Sy Chen, Chin-wen Chou, David Hume, David Leibrandt
We describe a framework for calculating the frequency shift and uncertainty of trapped-ion optical atomic clocks caused by background-gas collisions, and apply this framework to an 27Al+ quantum-logic clock to enable a total fractional systematic

An 27 Al+ quantum-logic clock with systematic uncertainty below 10 -18

July 15, 2019
Author(s)
Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, Ethan Clements, Chin-wen Chou, David J. Wineland, David Hume, David Leibrandt
We describe an optical atomic clock based on quantum-logic spectroscopy of the 1S 0 3P 0 transition in 27Al + with a systematic uncertainty of 9.0 x 10-19 and a frequency stability of 1.2 X 10 -15/(T 1/2). A 25Mg + ion is simultaneously trapped with 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

Preparation and coherent manipulation of pure quantum states of a single molecular ion

May 11, 2017
Author(s)
Chin-Wen Chou, Christoph Kurz, David B. Hume, Philipp N. Plessow, David R. Leibrandt, Dietrich G. Leibfried
Laser cooling and trapping of atoms and atomic ions has led to breakthroughs in understanding of exotic phases of matter [1-3], development of exquisite sensors [4] and state-of-the-art atomic clocks [5]. For molecules, with their more complicated internal

Hyperfine-mediated electric quadrupole shifts in Al+ and In+ ion clocks

April 6, 2017
Author(s)
Kyle P. Beloy, David R. Leibrandt, Wayne M. Itano
We evaluate the electric quadrupole moments of the 1S0 and 3P0 clock states of 27Al+ and 115In+. To capture all dominant contributions, our analysis extends through third order of perturbation theory and includes hyperfine coupling of the electrons to both

Sympathetic Ground State Cooling and Time-dilation Shifts in an 27Al+ Optical Clock

February 3, 2017
Author(s)
Jwo-Sy Chen, Samuel M. Brewer, David B. Hume, Chin-Wen Chou, David J. Wineland, David R. Leibrandt
We report Raman sideband cooling of 25Mg+ to sympathetically cool the secular modes of motion in a 25Mg+-27Al+ two-ion pair to near the three-dimensional (3D) ground state. The evolution of the Fock state distributions during the cooling process is studied

Trapped-ion optical atomic clocks at the quantum limits

January 31, 2017
Author(s)
David R. Leibrandt, Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, David B. Hume, David J. Wineland, Chin-Wen Chou
Frequency and its inverse, time, are the most accurately measured quantities. Historically, improvements in the accuracy of clocks have enabled advances in navigation, communication, and science. Since 1967, the definition of the SI second has been based

Probing beyond the laser coherence time in optical clock comparisons

March 30, 2016
Author(s)
David B. Hume, David R. Leibrandt
We develop protocols that circumvent the laser noise limit in optical clock comparisons by synchronous probing of two clocks using phase-locked local oscillators. This allows for probe times longer than the laser coherence time, avoids the Dick effect, and

Exponential scaling of clock stability with atom number

March 28, 2015
Author(s)
Till P. Rosenband, David R. Leibrandt
In trapped-atom clocks, the primary source of decoherence is often the phase noise of the oscillator. In this case, it is theoretically possible to derive exponential performance gains by combining several atomic ensembles. For example, M ensembles of N

Shifts of optical frequency references based on spectral hole burning in Eu3+:Y2SiO5

March 6, 2013
Author(s)
David R. Leibrandt, Michael J. Thorpe, Till P. Rosenband
Spectral hole burning laser frequency stabilization in Eu3+:Y2SiO5 is performed in a cryogenic environment with high temperature stability and low levels of vibration. Several properties of Eu3+:Y2SiO5 spectral holes are measured, including magnetic field

Cavity-stabilized laser with acceleration sensitivity below 10 -12 /g -1

February 21, 2013
Author(s)
David R. Leibrandt, James C. Bergquist, Till P. Rosenband
We characterize the frequency-sensitivity of a cavity-stabilized laser to inertial forces and temperature fluctuations, and perform real-time feed-forward to correct for these sources of noise. We measure the sensitivity of the cavity to linear

Trapped-Ion State Detection through Coherent Motion

December 9, 2011
Author(s)
Till P. Rosenband, David Hume, Chin-Wen Chou, David R. Leibrandt, Michael J. Thorpe, David J. Wineland
Coherent control of trapped atomic ions has led to several recent advances in quantum information processing 1 and precision spectroscopy 2. A basic requirement for these and other quantum-metrology experiments is the ability to detect the state of an

Field-test of a robust, portable, frequency-stable laser

May 10, 2011
Author(s)
David R. Leibrandt, Michael J. Thorpe, James C. Bergquist, Till P. Rosenband
We operate a frequency-stable laser in a non-laboratory environment where the test platform is a passenger vehicle. We measure the acceleration experienced by the laser and actively correct for it to achieve a system acceleration sensitivity of df/f = 11(2

Spherical Reference Cavities for Ultra-Stable Lasers in Non-Laboratory Environments

February 14, 2011
Author(s)
David R. Leibrandt, Michael J. Thorpe, Mark Notcutt, Robert E. Drullinger, Till P. Rosenband, James C. Bergquist
We present an ultra-stable optical cavity design that is insensitive to both vibrations and orientation. The design is based on a spherical cavity spacer which is held rigidly at two points on a diameter of the sphere. Coupling of the support forces to the