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Search Publications

NIST Authors in Bold

Displaying 1051 - 1075 of 2466

Multivariable Extrapolation of Grand Canonical Free Energy Landscapes

December 21, 2017
Author(s)
Nathan Mahynski, Jeffrey R. Errington, Vincent K. Shen
We derive an approach for extrapolating the free energy landscape of multicomponent systems in the grand canonical ensemble, obtained from flat- histogram Monte Carlo simulations, from one set of temperature and chemical potentials to another. This is

High-harmonic generation in periodically poled waveguides

December 19, 2017
Author(s)
Daniel D. Hickstein, David R. Carlson, Abijith S. Kowligy, Matt Kirchner, Scott Domingue, Nima Nader, Henry R. Timmers, Alexander J. Lind, Gabriel G. Ycas, Margaret Murnane, Henry Kapteyn, Scott B. Papp, Scott A. Diddams
Optical waveguides made from periodically poled materials provide high confinement of light and enable the generation of new wavelengths via quasi-phase-matching, making them a key platform for nonlinear optics and photonics. However, such devices are not

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
Displaying 1051 - 1075 of 2466
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