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Displaying 1526 - 1550 of 2503

The Half-Life of 209Po : Revisited

August 13, 2014
Author(s)
Ronald Colle, Ryan P. Fitzgerald, Lizbeth Laureano-Perez
A substantial 25 % error in the then known and accepted (102  5) year half-life of 209Po was reported on in 2007. This error was detected from decay data from two separate primary standardizations of a 209Po solution standard, which were performed

EUV spectra of Rb-like to Ni-like dysprosium ions in an electron beam ion trap

August 12, 2014
Author(s)
Deirdre Kilbane, G. O'Sullivan, Yuri A. Podpaly, John D. Gillaspy, Joseph Reader, Yuri Ralchenko
Extreme ultraviolet radiation emitted from highly-charged dysprosium ions was measured at the National Institute of Standards and Technology. The ions were created, trapped, and excited in an electron beam ion trap (EBIT), and the spectra were recorded

Measurement of High-Energy (10 keV to 60 keV) X-Ray Spectral Line Widths with eV Accuracy

August 8, 2014
Author(s)
John F. Seely, Jack L. Glover, Lawrence T. Hudson, Yuri Ralchenko, Nino R. Pereira, U. Feldman, C. D. Stefan
A high resolution crystal spectrometer (HRCS) utilizing a crystal in transmission geometry has been developed and experimentally optimized to measure the line widths of emission lines in the 10 keV to 60 keV energy range with eV accuracy. The spectrometer

Optically-Pumped Magnetometers for MEG

August 8, 2014
Author(s)
Svenja A. Knappe, Tillman H. Sander, Lutz Trahms
Optically-pumped magnetometers (OPMs) have seen rapid progress over the last decade in terms of performance and technology development. As highly sensitive room-temperature magnetometers they present several advantages over SQUID sensors, such as the

Single-Mode Optical Fiber For High-Power, Low-Loss UV Transmission

August 8, 2014
Author(s)
Daniel H. Slichter, Yves Colombe, Andrew C. Wilson, Dietrich G. Leibfried, David J. Wineland
We report large-mode-area solid-core photonic crystal fibers made from fused silica which resist UV solarization even at relatively high optical powers. Using a process of hydrogen loading and UV irradiation of the fibers, we demonstrate stable single-mode

Speckle phase noise in coherent laser ranging: fundamental precision limitations

August 8, 2014
Author(s)
Esther Baumann, Jean-Daniel Deschenes, Fabrizio R. Giorgetta, William C. Swann, Ian R. Coddington, Nathan R. Newbury
Frequency-modulated continuous-wave laser detection and ranging (FMCW LADAR) measures the range to a surface through coherent detection of the backscattered light from a frequency-swept laser source. The ultimate limit to the range precision of FMCW LADAR

Tunable spin-spin interactions and entanglement of ions in separate controlled potential wells

August 7, 2014
Author(s)
Andrew C. Wilson, Yves Colombe, K. R. Brown, Emanuel H. Knill, Dietrich G. Leibfried, David J. Wineland
Inspired by the ideas of Richard Feynman, 1 David Deutsch, 2 Seth Lloyd 3 and others, researchers in the field of quantum information processing and simulation seek to harness the quantum-mechanical properties of well-controlled laboratory systems to

Enriching 28Si beyond 99.9998 % for semiconductor quantum computing

August 5, 2014
Author(s)
Kevin J. Dwyer, Joshua M. Pomeroy, David S. Simons, June W. Lau, Kristen L. Steffens
Using a laboratory-scale apparatus, we enrich 28Si and produce material with 40 times less residual 29Si than previously reported. Starting from natural abundance silane gas, we offer an alternative to industrial gas centrifuges for providing materials

Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer

July 31, 2014
Author(s)
John E. Kitching, P. Ganssle, H Shin, Scott J. Seltzer, Vikram S. Bajaj, Micah P. Ledbetter, Dimitry Budkerl, Svenja A. Knappe, A Pines
In this work, we have demonstrated for the first time that an alkali vapor cell magnetometer has sufficient sensitivity to chemically resolve a heterogeneous mixture of oil and water by its relaxation and diffusion properties, both in one dimensional

Extended Analysis of the Spectrum of Singly Ionized Chromium (Cr II)

July 23, 2014
Author(s)
Craig J. Sansonetti, Gillian Nave
We have made new observations of the spectrum of singly-ionized chromium (Cr II) in the region 2850 Angstrom to 37900 Angstrom with the National Institute of Standards and Technology 2 m Fourier transform spectrometer. These data extend our previously

Electro-optical frequency division and stable microwave synthesis

July 19, 2014
Author(s)
Scott A. Diddams, Jiang Li, Xu Li, Hansuek Lee, Kerry J. Vahala
Optical frequency division using a mode-locked- laser, frequency comb has revolutionized time keeping and the generation of stable microwave signals. A different approach for optical frequency division and microwave generation using a comb of frequencies

Modulated Electromechanics: Large Enhancements of Nonlinearities

July 16, 2014
Author(s)
Raymond W. Simmonds, Jie-Qiao Liao, Kurt Jacobs, Franco Nori
It is well-known that the nonlinear coupling between a mechanical oscillator and a superconducting oscillator or optical cavity can be used to generate a Kerr-nonlinearity for the cavity mode. We show that the strength of this Kerr-nonlinearity, as well as

Effect of Impurities on Water Triple Point Cells

July 15, 2014
Author(s)
A Peruzzi, J. van Geel, A. Uytun, M. Kalemci, E. Uysal, Gregory F. Strouse, Yoana Y. Nuevo Ordonez, William Davis
Water triple point cells are the basis for the definition of the Kelvin and for the realization of the International Temperature Scale of 1990. The temperature differences between the cells are mainly caused by impurities arising in the cell water from the

Extreme ultraviolet spectra and analysis of ?n=0 transitions in highly charged barium

July 4, 2014
Author(s)
Joseph Reader, John D. Gillaspy, Dmitry D. Osin, Yuri Ralchenko
Extreme ultraviolet spectra of highly charged barium atoms were produced with an electron beam ion trap (EBIT) and recorded with a flat-field grazing-incidence spectrometer. The spectra were measured in the wavelength range 4 nm to 24 nm with the beam

Microresonator frequency comb optical clock

July 1, 2014
Author(s)
Scott B. Papp, Katja M. Beha, Pascal P. Del'Haye, Franklyn J. Quinlan, Hansuek Lee, Kerry J. Vahala, Scott A. Diddams
Optical frequency combs enable measurement precision at the 20th digit, and measurement accuracy entirely commensurate with their reference oscillator. A new direction in experiments is the creation of ultracompact frequency combs by way of nonlinear

State of the Art Raman Techniques for Biological Applications

July 1, 2014
Author(s)
Angela R. Hight Walker, Alasdair Rae, Rainer Stosch, Petr Klapetek, Debdulal Roy
Raman spectroscopy is a powerful tool for the elucidation of qualitative and quantitative information from biological systems and has huge potential in areas such as biotechnologies, drug discovery, agro-chemical research and clinical diagnostics. This

Tests of Theory in Rydberg States of One-electron Ions

July 1, 2014
Author(s)
Joseph N. Tan, Peter J. Mohr
Comparison of optical frequency measurements to predictions of quantum electrodynamics (QED) for Rydberg states of one-electron ions can test theory and allow new determinations of constants of nature to be made. Simplifications in the QED theory of high

Photon-Efficient High-Dimensional Quantum Key Distribution

June 12, 2014
Author(s)
Tian Zhong, Hongchao Zhou, Ligong Wang, Gregory Wornell, Zheshen Zhang, Jeffrey Shapiro, Franco N. Wong, Rob Horansky, Varun Verma, Adriana Lita, Richard Mirin, Thomas Gerrits, Sae Woo Nam, Alessandro Restelli, Joshua Bienfang, Francesco Marsili, Matthew Shaw
We demonstrate two high-dimensional QKD protocols - secure against collective Gaussian attacks - yielding up to 8.6 secure bits per photon and 6.7 Mb/s throughput, with 6.9 bits per photon after transmission through 20 km of fiber.
Displaying 1526 - 1550 of 2503
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