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Search Publications

NIST Authors in Bold

Displaying 1451 - 1475 of 2587

DBSR_HF: A B-spline Dirac-Hartree-Fock program

January 8, 2016
Author(s)
O Zatsarinny, Charlotte F. Fischer
A B-spline version of a general Dirac-Hartree-Fock program is described. The usual differential equations are replaced by set of generalized eigenvalue problems of the form (Ha . åa B)Pa = 0, where Pa designates the two-component relativistic orbital in B

Spectrum and Energy Levels of Five-Times Ionized Zirconium (Zr VI)

January 5, 2016
Author(s)
Joseph Reader, Mark D. Lindsay
The spectrum of five-times-ionized zirconium Zr VI was observed from 160 Å to 2000 Å with sliding spark discharges on 10.7-m normal- and grazing-incidence spectrographs. The existing analysis of this spectrum [Khan Z. A. et al. 1985 Phys. Scr. 31 837] was

NIST Time and Frequency Bulletin

January 1, 2016
Author(s)
Karen L. Hansen Lichtfuss
The Time and Frequency Bulletin provides information on performance of time scales and a variety of broadcasts (and related information) to users of the NIST services

Direct observation of Feshbach enhanced s-wave scattering of fermions

December 17, 2015
Author(s)
Dina Genkina, Lauren M. Aycock, Hsin I Lu, Ian B. Spielman, Benjamin K. Stuhl
We directly measured the s-wave scattering cross-section of ultracold 40K atoms across the 20.2 mT Feshbach resonance by colliding pairs of degenerate Fermi gases (DFGs) and imaging the scattered atoms. Owing to DFG’s low density, few atoms scattered, even

Multi-element logic gates for trapped-ion qubits

December 17, 2015
Author(s)
Ting Rei Tan, John P. Gaebler, Yiheng Lin, Yong Wan, Ryan S. Bowler, Dietrich G. Leibfried, David J. Wineland
Precision control over hybrid physical systems at the quantum level is of general importance in physics. For trapped-ions, a hybrid system formed of different species introduces extra degrees of freedom that can be exploited to expand and refine the

A strong loophole-free test of local realism

December 16, 2015
Author(s)
Lynden K. Shalm, Evan Meyer-Scott, B. G. Christensen, Peter L. Bierhorst, Michael A. Wayne, Deny Hamel, Martin J. Stevens, Thomas Gerrits, Scott C. Glancy, Michael S. Allman, Kevin J. Coakley, Shellee D. Dyer, Adriana E. Lita, Varun B. Verma, Joshua C. Bienfang, Alan L. Migdall, Yanbao Zhang, William Farr, Francesco Marsili, Matthew D. Shaw, Jeffrey Stern, Carlos Abellan, Waldimar Amaya, Valerio Pruneri, Thomas Jennewein, Morgan Mitchell, P. G. Kwiat, Richard P. Mirin, Emanuel H. Knill, Sae Woo Nam
We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high

Accurate multiconfiguration calculations of energy levels, lifetimes and transition rates for the silicon isoelectronic sequence: Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX

December 6, 2015
Author(s)
P. Jonsson, L Radziute, G. Gaigalas, M. Godefroid, J P. Marques, T Brage, Charlotte F. Fischer, I. P. Grant
Multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations and relativistic configuration interaction (RCI) calculations are performed for states of the 3s23p2, 3s3p3 and 3s23p3d configurations in the Si-like ions Ti IX - Ge XIX, Sr XXV, Zr XXVII, Mo XXIX

Observation of Iron Spin-States using Tabletop X-ray Emission Spectroscopy and Microcalorimeter Sensors

December 2, 2015
Author(s)
Young Il Joe, Galen C. O'Neil, Luis Miaja Avila, Joseph W. Fowler, Kevin L. Silverman, Daniel S. Swetz, Joel N. Ullom, Ralph Jimenez
X-ray emission spectroscopy (XES) is a powerful probe of the electronic and chemical state of elemental species embedded within more complex compounds. X-ray sensors that combine high resolving power and high collecting efficiency are desirable for photon

Exciton-dominated Dielectric Function of Atomically Thin MoS2 Films

November 24, 2015
Author(s)
Yilin Yu, Yifei Yu, Yongqing Cui, Wei Li, Gurarslan Alper, Peelaers Hartwin, Aspnes David, Chris Van de Walle, Nhan Van Nguyen, Zhang Yong-Wei, Linyou Cao
The control of photons by field effects, like the gating of electrons, can revolutionize a wide range of fields by enabling active photonic devices whose functions could be manipulated with sophistication and speeds comparable to what achieved in modern

Adapting the Poisson-Influenced K-Means Algorithm for a Larger User Base

November 19, 2015
Author(s)
Brian P. Morris, Zachary H. Levine
A superconducting transition edge sensor (TES) can be a useful tool for counting the number of photons in a highly attenuated pulse of light, but it requires calibration for its outputs to be interpretable as photon numbers. The Poisson-Influenced K-Means

Chemical potential for light

November 19, 2015
Author(s)
Jacob M. Taylor, Mohammad Hafezi, Prabin Adhikari
Photons are not conserved in interactions with other matter. Consequently, when understanding the equation of state and thermodynamics of photons, while we have a concept of temperature for energy conservation, there is no equivalent chemical potential for

Gold Nanoparticle Quantitation by Whole Cell Tomography

November 13, 2015
Author(s)
Aric W. Sanders, Kavita M. Jeerage, Cindi Schwartz, Alexandra Curtin, Ann C. Chiaramonti Debay
Many proposed biomedical applications for engineered gold nanoparticles require their incorporation by mammalian cells in specific numbers and locations. Here, the number of gold nanoparticles inside of individual mammalian stem cells was characterized

Schwere Experimente

November 1, 2015
Author(s)
Stephan Schlamminger, Christian Rothleitner
Obwohl die Standardunsicherheit der Gravitationskonstante in der neuesten Veröffentlichung des CODATA um über die Hälfte reduziert wurde, ist sie noch immer die am ungenauesten bestimmte Naturkonstante.

NIST on a Chip: Realizing SI units with microfabricated alkali vapour cells

October 16, 2015
Author(s)
John E. Kitching, Elizabeth A. Donley, Svenja A. Knappe, Matthew T. Hummon, Argyrios Dellis, Jeffrey A. Sherman, Kartik A. Srinivasan, Vladimir A. Aksyuk, Qiliang Li, Daron A. Westly, Brian J. Roxworthy, Amit Lal
We describe several ways in which microfabricated alkali atom vapour cells might potentially be used to accurately realize a variety of SI units, including the second, the meter, the kelvin, the ampere and the volt, in a compact, low-cost “chip-scale”

Compact atom-interferometer gyroscope based on an expanding ball of atoms

October 12, 2015
Author(s)
Elizabeth A. Donley, John E. Kitching, Stefan Riedl, Gregory W. Hoth, Bruno M. Pelle
We present a compact atom interferometer based on 87Rb atoms that can simultaneously measure rotations and accelerations with a single source of atoms in a 300 cm3 vacuum package.

Measurement of the Microwave Lensing Shift in NIST-F1 and NIST-F2

October 12, 2015
Author(s)
Steven R. Jefferts, Stephan E. Barlow, Thomas P. Heavner, Neil Ashby
We present measurements of the microwave lensing frequency shift in the Primary Frequency Standards (PFS) NIST-F1 and NIST-F2. This frequency bias is reasonably controversial with differing theories giving quite different results. Our measurements are in
Displaying 1451 - 1475 of 2587
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