U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Samuel M. Brewer (Assoc)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 27

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

Quadruply-ionized barium as a candidate for a high-accuracy optical clock

October 23, 2020
Author(s)
Kyle Beloy, Vladimir A. Dzuba, Samuel M. Brewer
We identify Ba$^4+}$ (Te-like) as a promising candidate for a high-accuracy optical clock. The lowest-lying electronic states are part of a $^3P_J$ fine structure manifold with anomalous energy ordering, being non-monotonic in $J$. We propose a clock based

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

Capture of Highly Charged Ions in a Pseudo-Hyperbolic Paul Trap

July 12, 2019
Author(s)
Joan M. Dreiling, Aung S. Naing, Joseph N. Tan, Joshua Hanson, Shannon Hoogerheide, Samuel M. Brewer
The confinement of ions in a radio-frequency (RF) trap (also known as a Paul trap) has proven to be advantageous in many applications. Typically, singly- or few-times-ionized atoms can be created in situ within the ion trap. Highly charged ions, on the

Lifetime of the metastable 2 P 1/2 state of F-like Ar 9+ isolated in a compact Penning trap

September 6, 2018
Author(s)
Samuel M. Brewer, Joan M. Dreiling, Nicholas D. Guise, Shannon M. Hoogerheide, Aung Naing, Joseph N. Tan
Multiple-ionized atoms can be captured at low energy in a compact Penning trap, allowing the isolation of a single charge state to measure the radiative lifetime of an atomic state that decays via weakly allowed transitions. Such a measurement is reported

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

Experiments with highly-ionized atoms in unitary Penning traps

August 14, 2015
Author(s)
Shannon Hoogerheide, Aung Naing, Joan M. Dreiling, Samuel M. Brewer, Nicholas D. Guise, Joseph N. Tan
Highly-ionized atoms with special properties have been proposed for interesting applications, including potential candidates for a new generation of optical atomic-clocks at the 1 part in 1019 level of precision, quantum-information processing, and tests

Multiply-ionized Atoms Isolated at low energy in a Unitary Penning Trap

January 9, 2015
Author(s)
Joseph N. Tan, Shannon Hoogerheide, Samuel M. Brewer, Nicholas D. Guise
Ions extracted from the EBIT at NIST are slowed and captured in a Penning trap that is made very compact ( 150 cm3) by a unitary architecture. Measurements after 1 ms of ion storage indicate that the captured ions are distributed with 5(1) eV of energy

Measurement of the Kr XVIII 3d 2D5/2 lifetime in a Unitary Penning Trap

April 24, 2014
Author(s)
Nicholas D. Guise, Joseph N. Tan, Samuel M. Brewer, Charlotte F. Fischer, P. Jonsson
The lifetime of the 3d 2D5/2 in the fine-structure doublet of the Kr XVIII ground configuration is measured using a compact Penning trap with 2.2 cm3 of trapping volume. Kr17+ ions produced in an electron beam ion trap (EBIT) are extracted and captured in

Capture and isolation of highly-charged ions in a compact Penning trap: V12

December 4, 2013
Author(s)
Samuel M. Brewer, Nicholas D. Guise, Joseph N. Tan
Room-temperature, compact Penning traps have been shown recently to be useful for capture and storage of highly-charged ions extracted from an EBIT ion source at the National Institute of Standards and Technology (NIST). Highly-charged argon and neon ions

Light polarization and quantum interference effects in unresolvable atomic lines: application to a precise measurement of the 6,7Li D2 lines.

March 7, 2013
Author(s)
Roger C. Brown, Saijun Wu, James V. Porto, Craig J. Sansonetti, Clayton Simien, Samuel M. Brewer, Joseph N. Tan, John D. Gillaspy
We characterize the effect of quantum interference of light scattering on the line shapes and measured line positions in atomic spectra. These effects occur when the excited state splittings are of order the excited state line widths, and represent an

Towards One-electron Ions in Rydberg States for Laser Spectroscopy

July 30, 2012
Author(s)
Joseph N. Tan, Samuel M. Brewer, Nicholas D. Guise
Simple quantum systems play important roles in the determination of fundamental constants. Very recently at NIST, bare nuclei created in an EBIT were extracted and captured in a novel compact Penning trap. This is a step towards production of one-electron

Highly Charged Ions in Rare Earth Permanent Magnet Penning Traps

July 13, 2012
Author(s)
Nicholas D. Guise, Samuel M. Brewer, Joseph N. Tan
A newly constructed apparatus at the United States National Institute of Standards and Technology (NIST) is designed for the isolation, manipulation, and study of highly charged ions. Highly charged ions are produced in the NIST electron-beam ion trap

Penning traps with unitary architecture for storage of highly charged ions

February 15, 2012
Author(s)
Joseph N. Tan, Samuel M. Brewer, Nicholas D. Guise
Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used to produce 0.32 T for ion trapping in unitary architectures that functionally couple the electric and

Absolute transition frequencies and quantum interference in a frequency comb based measurement of the 6,7Li D lines

July 6, 2011
Author(s)
Craig J. Sansonetti, Clayton Simien, John D. Gillaspy, Joseph N. Tan, Samuel M. Brewer, Roger C. Brown, Saijun Wu, James V. Porto
Optical frequencies of the D lines of 6,7Li were measured with a relative accuracy of 5x10-11 using an optical comb synthesizer. Quantum interference in the laser induced fluorescence for the partially-resolved D2 lines was found to produce polarization

Experiment at NIST towards one-electron ions in circular Rydberg states

June 20, 2011
Author(s)
Joseph N. Tan, Samuel M. Brewer, Nicholas D. Guise
An experimental effort is underway at NIST to enable tests of theory with oneelectron ions synthesized in circular Rydberg states from captured bare nuclei. Problematic effects which limit the accuracy of predicted energy levels for low-lying states are

EUV Spectral Lines of Highly-Charged Hf, Ta and Au Ions Observed with an Electron Beam Ion Trap

January 12, 2011
Author(s)
Ilija Draganic, Yuri Ralchenko, Joseph Reader, John D. Gillaspy, Joseph N. Tan, Joshua M. Pomeroy, Samuel M. Brewer, Dmitry D. Osin
Extreme ultraviolet spectra of highly charged hafnium, tantalum, and gold were produced with an electron beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST) and recorded with a flat-field grazing-incidence spectrometer in the