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Search Publications

NIST Authors in Bold

Displaying 1176 - 1200 of 2588

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

Prospects for Magnetic Field Communications and Location Using Quantum Sensors

December 14, 2017
Author(s)
Vladislav P. Gerginov, Fabio C. Da Silva, David A. Howe
Signal attenuation limits the operating range in wireless communications and location. To solve the reduced range problem, one can use low-frequency signals in combination with magnetic sensing. We propose the use of an optically-pumped magnetometer as a

Relativistic theory of the falling retroreflector gravimeter

December 12, 2017
Author(s)
Neil Ashby
We develop a relativistic treatment of interference between light reflected from a falling cube retroreflector in the vertical arm of an interferometer, and light in a reference beam in the horizontal arm. Coordinates that are nearly Minkowskian, attached

Measurements of the Newtonian Constant of Gravitation, G

November 30, 2017
Author(s)
Christian Rothleitner, Stephan Schlamminger
The Newtonian Constant of Gravitation G seems to be the fundamental constant that is most difficult to measure accurately. In the past three decades more than a dozen precision measurements were performed. Unfortunately the scatter of the data points is

Ultra-high contrast coherent population trapping resonances in a cold-atom microwave clock

November 29, 2017
Author(s)
Xiaochi Liu, V. I. Yudin, A. V. Taichenachev, John Kitching, Elizabeth Donley
A cold-atom coherent population trapping clock can achieve a better long-term frequency stability than similar clocks based on vapor cells, since long interrogation periods are possible without introducing systematic frequency shifts from buffer gases

CRITICALLY EVALUATED SPECTRAL DATA FOR NEUTRAL CARBON (C I)

November 22, 2017
Author(s)
Haris Kunari, Alexander Kramida
In this critical compilation, all known to us experimental data on the spectrum of neutral carbon were methodically evaluated and supplemented by parametric calculations with Cowan's code. The sources of experimental data vary from laboratory to

String-like Collective Motion and Diffusion in the Interfacial Region of Ice

November 20, 2017
Author(s)
Jack F. Douglas, Hao Zhang, Xuhang Tong, Xinyi Wang
We investigate the collective molecular motions and diffusion of water molecules in the mobile interfacial region of the secondary prismatic plane of hexagonal ice by molecular dynamics simulation based on the TIP4P/2005 water potential and metrologies of

Flux-tunable phase shifter for microwaves

November 7, 2017
Author(s)
Roope J. Kokkoniemi, Tuomas Ollikainen, Sakari Saarenpaa, Janne Kokkala, Ceren Dag, Mikko Mottonen, Russell Lake
We introduce a magnetic-flux-tunable phase shifter for propagating microwave photons, based on three equidistant superconducting quantum interference devices (SQUIDs) on a transmission line. We experimentally implement the phase shifter and demonstrate

High-Performance Coherent Population Trapping Clock Based on Laser-Cooled Atoms

November 2, 2017
Author(s)
Xiaochi Liu, Eugene Ivanov, V. I. Yudin, John Kitching, Elizabeth Donley
Atomic clocks based on laser-cooled atoms are capable of achieving long interrogation periods and hence narrow resonance linewidths because of the very low atom velocities achievable with laser cooling. The long interrogation periods are achieved without

Radiative rates of transitions from the 2s2p3 5Sdeg2 state in neutral carbon

November 1, 2017
Author(s)
Alexander Kramida, Haris Kunari
The measured radiative rates of the 2s22p2 3P1,2 – 2s2p3 5S°2 intercombination transitions in neutral carbon reported in the literature are critically evaluated in comparison with theoretical results. The experimental and theoretical values are compared

Perspectives for a new realization of the pascal by optical methods

October 24, 2017
Author(s)
Jay H. Hendricks, Karl Jousten, Jack A. Stone Jr., Patrick F. Egan, Tom Rubin, Christof Gaiser, Rene Schodel, James A. Fedchak, Jacob E. Ricker, Jens Fluegge, Stephen P. Eckel, Julia K. Scherschligt, Daniel S. Barker, Kevin O. Douglass, Gregory F. Strouse, Uwe Sterr, Waldimir Sabuga
Since the beginning of measurement of pressure in the 17th century, the unit of pressure has been defined by the relationship of force per unit area. The present state of optical technology now offers the possibility of using a thermodynamic definition

UV superconducting nanowire single-photondetectors with high efficiency, low noise, and4 K operating temperature

October 18, 2017
Author(s)
Varun Verma, Adriana Lita, Richard Mirin, Sae Woo Nam, Emma Wollman, Andrew Beyer, Ryan Briggs, Francesco Marsili, Jason Allmaras, Matthew Shaw
For photon-counting applications at ultraviolet wavelengths, there are currently nodetectors that combine high efficiency (> 50%), sub-nanosecond timing resolution, and sub-Hz dark count rates. Superconducting nanowire single-photon detectors (SNSPDs) have

JY1 Time Scale: a New Kalman-Filter Time Scale Designed at NIST

October 17, 2017
Author(s)
Jian Yao, Thomas E. Parker, Judah Levine
We report on a new Kalman-filter Hydrogen-maser time scale (i.e., JY1 time scale) designed at NIST. The JY1 time scale is composed of a few Hydrogen masers and a Cs clock. The Cs clock is used as a reference clock, to ease operations with existing data
Displaying 1176 - 1200 of 2588
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