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Displaying 1951 - 1975 of 2503

Atomic Spectroscopic Databases at NIST

October 28, 2010
Author(s)
Joseph Reader, Alexander Kramida, Yuri Ralchenko
We present recent work at NIST to develop and maintain databases for spectra, transition probabilities, and energy levels of atoms that are astrophysically important. We also describe our programs to critically compile these data as well as the recently

Towards More Accurate Atomic Oscillator Strengths

October 28, 2010
Author(s)
Wolfgang L. Wiese, Jeffrey R. Fuhr, John M. Bridges
Accurate determinations of atomic oscillator strengths have been a problem for a long time, and discrepancies between various numerical results have been substantial. But in recent years considerable progress has been made, especially for weak lines

SIM time scales

October 27, 2010
Author(s)
Michael A. Lombardi, J. Mauricio Lopez-Romero, Nelida Diaz-Munoz
This paper presents an analysis of the performance of some of the time scales generated in the Sistema Interamericano de Metrologia (SIM) region. We emphasize the generation of the first international time scale in near real time, the SIM Time scale (SIMT)

The evolving optical frequency comb

October 22, 2010
Author(s)
Scott A. Diddams
Much as natural historians search for the first roots of our human race, curiosity drives the laser scientist to pursue the roots of his or her own field. This is especially the case in this year where our community celebrates the 50th anniversary of the

Characterization of a Soluble Anthradithiophene Derivative

October 1, 2010
Author(s)
Brad Conrad, Calvin Chan, Marsha A. Loth, Sean R. Parkin, Xinran Zhang, John E. Anthony, David J. Gundlach
The structural and electrical properties of a new solution processable material, 2,8-diflouro-5,11-tert-butyldimethylsilylethynl anthradithiophene (TBDMS), were measured for single crystal and spun cast thin-film transistors. TBDMS is observed to readily

Revised interpretation of the Na I EUV absorption spectrum

September 27, 2010
Author(s)
Alexander Kramida
Spectral data for neutral sodium were recently compiled by Sansonetti (2008 J. Phys. Chem. Ref. Data 37 1659). In that compilation, some of the energy levels of the 2p53snl configurations were quoted from the studies of the absorption spectrum in the

Relativity and Optical Clocks

September 24, 2010
Author(s)
Chin-Wen Chou, David Hume, Till P. Rosenband, David J. Wineland
Albert Einstein's theory of relativity forced us to alter our concepts of reality. One of the more startling outcomes of the theory is that we have to give up our notions of simultaneity. This is manifest in the so-called twin paradox in which a twin

Toward Spin Squeezing with Trapped Ions

September 23, 2010
Author(s)
John J. Bollinger, Hermann Uys, Michael Biercuk, Joseph W. Britton
Building robust instruments capable of making interferometric measurements with precision beyond the standard quantum limit remains an important goal in many metrology laboratories. We describe here the basic concepts underlying spin squeezing experiments

On-Board Signal Integrity for GPS

September 21, 2010
Author(s)
Marc A. Weiss, Pradipta Shome, Ron Beard
The elements of a space-based integrity approach are to monitor the signals on-board the satellite, such that signal performance can be maintained well within desired integrity limits. These elements include 1) a system for monitoring multiple atomic

The Cooper Pair Transistor

September 17, 2010
Author(s)
Jose A. Aumentado
The Cooper pair transistor (CPT) is a superconducting electrometer that has applications in quantum information as well as fundamental superconductivity studies. Since it operates in a near-dissipationless mode, it has potential as a minimally invasive

Generation of optical coherent-state superpositions by number-resolved photon subtraction from the squeezed vacuum

September 9, 2010
Author(s)
Thomas Gerrits, Scott C. Glancy, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron Miller, Aaron J. Miller, Alan L. Migdall, Sae Woo Nam, Richard P. Mirin, Emanuel H. Knill
We have created heralded coherent-state superpositions (CSSs) by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving transition edge sensor to

Sub-micron force detection using optically-cooled levitated microspheres

September 3, 2010
Author(s)
Andrew Geraci, Scott B. Papp, John E. Kitching
We propose an experiment using optically trapped and cooled dielectric microspheres for the detection of short-range forces. The center-of-mass motion of a microsphere trapped in vacuum can experience extremely low dissipation and quality factors of 10 12

Reflectance Factor Measurement Complications Due to Near Infrared Fluorescence

September 1, 2010
Author(s)
Maria E. Nadal, Carl C. Miller, Clarence J. Zarobila
The researchers at the National Institute of Standards and Technology (NIST) have found that the widely used orange and red color tiles unexpectedly exhibit near infrared fluorescence. An analysis of the effect this fluorescence component has on the

The Development of a Unified Time and Frequency Program in the SIM Region

September 1, 2010
Author(s)
Michael A. Lombardi, J. Mauricio Lopez-Romero
The Sistema Interamericano de Metrologia (SIM) is one of five major regional metrology organizations (RMOs) recognized by the Bureau International des Poids et Mesures (BIPM). SIM is composed of the national metrology institutes (NMIs) located in the 34

Temperature dependence of the diffusive conductivity of bilayer graphene

August 24, 2010
Author(s)
Shaffique Adam, Mark D. Stiles
Assuming diffusive carrier transport and employing an effective medium theory, we calculate the temperature dependence of bilayer graphene conductivity due to Fermi-surface broadening as a function of carrier density. We find that the temperature

yocto-Newton force detection sensitivity using trapped ions

August 22, 2010
Author(s)
Michael J. Biercuk, Joseph W. Britton, Hermann Uys, Aaron Vandevender, John Bollinger
Recent experimental advances have shown that it is possible to detect forces arising from electric fields at a level of aN/ √Hz (atto = 10 -18 through coupling of micro or nanofabricated mechanical resonators to a variety of physical systems including

Advances in Coherent Population Trapping for Atomic Clocks

August 10, 2010
Author(s)
John E. Kitching, Vishal Shah
We review advances in the field of coherent population trapping (CPT) over the last decade with respect to the application of this physical phenomenon to atomic frequency references. We provide an overview of both the basic phenomenon of coherent
Displaying 1951 - 1975 of 2503
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