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Displaying 1301 - 1325 of 2503

Surrogate Gas Prediction Model as a Proxy for {D}14C-Based Measurements of Fossil Fuel-CO2

June 27, 2016
Author(s)
Kevin J. Coakley, Benjamin Miller, Stephen A. Montzka, Colm Sweeney, Ben Miller, John B. Miller
In contrast to CO2 produced in the atmosphere by all other sources, CO2 produced by the combustion of fossil fuels is devoid of 14C. Thus, the measured 14C: 12C isotopic ratio of atmospheric CO2 (and its associated derived {Δ}14C value) is an ideal tracer

Vibration-induced field fluctuations in a superconducting magnet

June 27, 2016
Author(s)
Joseph W. Britton, John J. Bollinger, Justin G. Bohnet, Brian C. Sawyer, Hermann Uys, Michael Biercuk
Superconducting magnets enable precise control of nuclear and electron spins, and are used in experiments that explore biological and condensed matter systems, and fundamental atomic particles. In high-precision applications, a common view is that that

Microresonator Brillouin laser stabilization using a microfabricated rubidium cell

June 17, 2016
Author(s)
William Loh, Matthew T. Hummon, Holly Leopardi, Tara Fortier, Franklyn Quinlan, John Kitching, Scott Papp, Scott Diddams
We frequency stabilize the output of a miniature stimulated Brillouin scattering (SBS) laser to rubidium atoms in a microfabricated cell to realize a laser system with frequency stability at the 10-11 level over seven decades in averaging time. In addition

Low Helium Permeation Cells for Atomic Microsystems Technology

June 15, 2016
Author(s)
Argyrios Dellis, Shah Vishal, Elizabeth A. Donley, Svenja A. Knappe, John E. Kitching
The miniaturization of instruments and sensors based on laser-cooled atoms is hindered by the large pumps needed to maintain the vacuum requirements. A significant source of vacuum contamination is the permeation of gases through the walls of the chamber

Quantum spin dynamics and entanglement generation with hundreds of trapped ions

June 15, 2016
Author(s)
Justin G. Bohnet, Brian C. Sawyer, Joseph W. Britton, Michael L. Wall, A M. Rey, Michael S. Foss-Feig, John J. Bollinger
Quantum simulation of spin models can provide insights into a variety of hard problems, including the competition between entanglement and decoherence in open quantum systems. Trapped ions are an established platform for quantum simulation, but only

Precision measurement of the radiative beta decay of the free neutron

June 14, 2016
Author(s)
Jeffrey S. Nico, Kevin J. Coakley, Maynard S. Dewey, Thomas R. Gentile, Hans P. Mumm, Alan Keith Thompson, M J. Bales, R. Alarcon, C. D. Bass, E J. Beise, H Breuer, Jim Byrne, R L. Cooper, B. O'Neill, F E. Wietfeldt, T E. Chupp
The theory of quantum electrodynamics predicts that a continuous spectrum of photons is emitted in the beta decay of the free neutron in addition to a proton, an electron, and an antineutrino. We report the first precision test of the shape of the photon

Arrays of individually controlled ions suitable for two-dimensional quantum simulations

June 13, 2016
Author(s)
Manuel Mielenz, Henning Kalis, Matthias Wittemer, Frederick Hakelberg, Roman Blain, Peter Maunz, Dietrich Leibfried, Tobias Schaetz
A custom-built and precisely controlled quantum system may o ffer access to a fundamental understanding of another, less accessible system of interest. A universal quantum computer is currently out of reach, but an analog quantum simulator (AQS) that makes

Invited Article: MiniTimeCube

June 13, 2016
Author(s)
Hans P. Mumm
We present the development of the miniTimeCube (mTC), the world’s smallest neutrino detector. The mTC is a multipurpose detector, aiming to detect not only neutrinos but also fast/thermal neutrons and gammas. Potential applications include the

Observation of Strong Reflection of Electron Waves Exiting a Ballistic Channel at Low Energy

June 10, 2016
Author(s)
Jason Campbell, Jason Ryan, Kin P. Cheung, David J. Gundlach, Changze Liu, Canute I. Vaz, Richard G. Southwick III, Anthony S. Oates, Ru Huang
Wave scattering by a potential step is a nearly ubiquitous concept. Thus, it is surprising that theoretical treatments of ballistic transport in nanoscale devices, from quantum point contacts to ballistic transistors, assume no reflection even when the

Phase-coherent microwave-to-optical link with a self-referenced microcomb

June 6, 2016
Author(s)
Pascal P. Del'Haye, Aurelien C. Coillet, Tara M. Fortier, Katja M. Beha, Daniel C. Cole, Hansuek Lee, Kerry J. Vahala, Scott B. Papp, Scott A. Diddams
The counting and control of optical cycles of light has become common with modelocked laser frequency combs. But even with advances in laser technology, modelocked laser combs remain bulk-component devices that are hand-assembled. In contrast, a frequency

Single-frequency 571 nm VECSEL for photoionization of magnesium

June 3, 2016
Author(s)
Shaun C. Burd, Tomi Leinonen, Jussi-Pekka Penttinen, David T. Allcock, Daniel H. Slichter, Raghavendra Srinivas, Andrew C. Wilson, Micrea Guina, Dietrich G. Leibfried
We report the development of an intracavity-frequency-doubled VECSEL emitting at 571 nm for photoionization of magnesium. The laser employs a V-cavity geometry with a gain chip at the end of one cavity arm and a lithium triborate (LBO) crystal for second

Oscillator metrology with software defined radio

May 24, 2016
Author(s)
Jeffrey A. Sherman, Robert Jordens
Analog electrical elements such as mixers, filters, transfer oscillators, isolating buffers, dividers, and even transmission lines contribute technical noise and unwanted environmental coupling in time and frequency measurements. Software defined radio

Visualizing edge states with an atomic Bose gas in the quantum Hall regime

May 19, 2016
Author(s)
Ian B. Spielman, Ben Stuhl, Hsin I Lu, Lauren M. Aycock, Dina Genkina
We engineered a two-dimensional magnetic lattice in an elongated strip geometry, with effective per-plaquette flux $\approx4/3$ times the flux quanta. We imaged the localized edge and bulk states of atomic Bose-Einstein condensates in this strip. Further

State of the Field: Extreme Precision Radial Velocities

May 17, 2016
Author(s)
Debra A. Fischer, Guillem Anglada-Escude, Pamela Arriagada, Roman V. Baluev, Jacob L. Bean, Lars A. Buchhave, Abhijit K. Chakraborty, Scott Diddams, Gabor Furesz, B. S. Gaudi, Philip C. Gregory, Frank Grundahl, Guillaume Hebrard, David W. Hogg, Andrew W. Howard, Colby A. Jurgenson, David W. Latham, Greg Laughlin, Thomas J. Loredo, Suvrath Mahadevan, Tyler M. McCracken, Mario R. Perez, David F. Phillips, P Plavchan, Lisa Prato, Andreas Quirrenbach, Paul Robertson, David Sawyer, Jason D. Eastman, Pedro Figueira, Eric B. Ford, Daniel Foreman-Mackey, Paul Fournier, John A. Johnson, Christophe Lovis, Francesco Pepe, Francesco Pepe, Ansgar Reiners, Nuno C. Santos, Damien Segransan, Alessandro Sozzetti, Thorsten Carroll, Francois Bouchy, Paul Jorden, Tilo Steinmetz, Xavier Dumusque, Artie P. Hatzes, Enrique Herrero, Michael Endl, Andrew Szentgyorgyi
The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm/s measurement precision. The presentations and discussion of key issues for

Testing of Cementitious Materials Using a Dynamic MEMS Micro Rheometer

May 17, 2016
Author(s)
Yong Sik Kim, Nicholas G. Dagalakis, Chiara C. Ferraris, Nicos Martys
Incompatibility of cementitious materials with admixtures often requires time consuming testing. Usually, several mixtures need to be prepared either using concrete or paste to determine the optimum high range water reducer dosage (HRWRA) and type. The

Electrical Units in the New SI: Saying Goodbye to the 1990 Values

May 12, 2016
Author(s)
Nick Fletcher, Gert Rietveld, James K. Olthoff, Ilya F. Budovsky
The proposed redefinition of several SI base units is a topic that has been on the metrology agenda for the last decade. The general principles and the motivation for the changes have been presented at the NCSLI several times. However, recent progress on

DELAY MEASUREMENT OF 1PPS SIGNALS IN TIMING SYSTEMS

May 9, 2016
Author(s)
Stefania Romisch, Daniele Rovera, Marco Siccardi
Abstract The uncertainty of time measurements in timing systems is not only a function of the quality of the instruments and system components (time interval counters, pulse distribution amplifiers, GNSS receivers) but lays also in the quality of the
Displaying 1301 - 1325 of 2503
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