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Physics

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Displaying 1201 - 1225 of 2516

Review of the 9th NLTE code comparison workshop

February 24, 2017
Author(s)
R. Piron, F. Gilleron, Y Aglitskiy, H.-K. Chung, C. J. Fontes, S. B. Hansen, O. Marchuk, H. Scott, E. Stambulchik, Yuri Ralchenko
We review the 9th NLTE code comparison workshop, which was held in the Jussieu campus, Paris, from November 30th to December 4th, 2015. This time, the workshop was mainly focused on a systematic investigation of iron NLTE steady-state kinetics and

Dynamical Heterogeneity in a Vapor-Deposited Polymer Glass

February 23, 2017
Author(s)
Jack F. Douglas, Wengang Zhang, Francis W. Starr
Recently, there has been great interest in 'ultrastable' glasses formed via vapor deposition, both because of emerging applications of these materials (e.g., active layers in light-emitting diodes and photovoltaics) and, theoretically, as materials for

Hybrid quantum systems with trapped charged particles

February 21, 2017
Author(s)
Shlomi S. Kotler, Raymond Simmonds, Dietrich Leibfried, David J. Wineland
Trapped charged particles have been at the forefront of quantum information processing (QIP) for a few decades now, with deterministic two-qubit logic gates reaching record fidelities of 99.9% and single-qubit operations of much higher fidelity. In a

Multi-configuration Dirac-Hartree-Fock calculations of forbidden transitions within the 3d^k ground configurations of highly charged ions (Z = 72 - 83)

February 21, 2017
Author(s)
Z.L. Zhao, K. Wang, S. Li, R. Si, C.Y. Chen, J. Yan, Yuri Ralchenko
Extensive self-consistent multi-configuration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 3s^2 3p^6 3d^k(k = 1−9) ground configurations of highly charged ions (Z = 72−83). Complete and consistent data sets of level energies,wavelengths

Analytical Tools for Point Source Interferometry

February 20, 2017
Author(s)
Gregory W. Hoth, John E. Kitching, Elizabeth A. Donley, Bruno M. Pelle
Light pulse atom interferometry can be used to realize high-performance sensors of accelerations and rotations. In order to broaden the range of applications of these sensors, it is desirable to reduce their size and complexity. Point source interferometry

6.00 Atomic Spectroscopy

February 19, 2017
Author(s)
Wolfgang L. Wiese
A compendium of basic facts, data and formulas of atomic spectroscopy is presented, to serve as part of a physicist s desk reference volume.

Advances in Atomic Structure Calculations

February 19, 2017
Author(s)
Charlotte F. Fischer
Correlation and relativistic effects are both needed for accurate atomic structure calculations of energy levels and their atomic properties. For transition probabilities between low-lying levels of a spectrum, accurate wave functions for the outer region

Laser Stabilization

February 19, 2017
Author(s)
John L. Hall, Jun Ye, M S. Taubman
It becomes clear that there are many interlinking considerations involved in the design of-laser stabilization systems, and it is difficult to present a full description in an article such as this. Still it is hoped that the reader will see some avenues to

Optics

February 19, 2017
Author(s)
Joseph Reader
The field of optics is summarized to assist in the solution of practical optics problems by working scientists. Over seventy formulas are presented dealing with reflection and refraction, absorption, lenses, mirrors, diffraction, interference, and spectra

Plasma Diagnostic Techniques

February 19, 2017
Author(s)
Eric C. Benck
In order for extreme ultraviolet (EUV) plasma sources to become the next generation lithographic source, significant obstacles still need to be overcome. Improvements in conversion efficiency (CE), plasma stability, and component lifetimes are required

Telling Time

February 19, 2017
Author(s)
Jonathan E. Hardis
In Low-Tech Blues [June], you note that we are surrounded by clocks, but lament the lack of systems to set them automatically. Our job is to help fix that. Your readers can use our time servers (www. Bldrdoc.gov/timefreq/service/its.htm) to automatically

Ultra-Cold Collisions of Atoms and Molecules

February 19, 2017
Author(s)
Paul S. Julienne
The study of collisions of neutral atoms and molecules at ultralow collision energies is made possible by advances in techniques for cooling and trapping such species. Excellent reviews of laser cooling of atoms are given in the Nobel Lectures of Chu 2

Revised analysis of the fifth spectrum of rhenium (Re V)

February 17, 2017
Author(s)
Vladimir I. Azarov, R R. Gayasov
The spectrum of rhenium was observed in the (500 to 2100) A wavelength region. A 6.65 m normal incidence VUV spectrograph has been used to record the spectrum. The (5d3 + 5d26s) - 5d26p transition array of four times ionized rhenium, Re V, has been

NIST Time and Frequency Bulletin

February 9, 2017
Author(s)
Kathryn R. Stephenson
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.

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

Ultrafast modulation of x-ray absorption by coherent phonon excitations

February 1, 2017
Author(s)
Eric L. Shirley, Jannick Weisshaupt, Michael Woerner, Marc J. Vrakking, Thomas Elsaesser, Andreas Borgschulte
X-ray absorption in solids promotes an electron from an atomic core level to the conduction band states, and near-edge spectra structure gives insight into local atomic geometry and chemical bonding effects. Based on a novel implementation of femtosecond x

A Clock Ensemble Using Only Active Hydrogen Masers

January 31, 2017
Author(s)
Thomas E. Parker, Stefania Romisch
The current real-time timescale at NIST, AT1, as well as the post-processed scale TP162, both contain hydrogen masers and commercial cesium frequency standards. The cesium standards are much nosier in the short term than the hydrogen masers and

A Study on Using the SDR Receiver for the Europe-Europe and Transatlantic TWSTFT Links

January 31, 2017
Author(s)
Victor S. Zhang, Thomas E. Parker, Joseph Achkar, Dirk Piester, Yi-Jiun Huang, Shinn-Yan Lin, Zhiheng Jiang
The BIPM and the CCTF Working Group on TWSTFT have stimulated a pilot study on using software defined radio (SDR) receivers for TWSTFT in the framework of the realization of International Atomic Time (TAI). The SDR receivers based on a software developed
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