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Displaying 876 - 900 of 2503

Experimental Upper Bound and Theoretical Expectations for Parity-Violating Neutron Spin Rotation in He-4

July 16, 2019
Author(s)
Jeffrey S. Nico, Hans P. Mumm, H E. Swanson, C. D. Bass, T. D. Bass, J M. Dawkins, J C. Horton, D Luo, William M. Snow, S. C. Walbridge, B. E. Crawford, K. F. Gan, A M. Micherdzinska, C. R. Huffer, D M. Markoff, Murad Sarsour, E I. Sharapov, V Zhumabekova, Blayne R. Heckel
Neutron spin rotation is expected from quark-quark weak interactions in the Standard Model, which induce weak interactions among nucleons that violate parity. We present the results from an experiment searching for the effect of parity violation via the

An 27 Al+ quantum-logic clock with systematic uncertainty below 10 -18

July 15, 2019
Author(s)
Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, Ethan Clements, Chin-wen Chou, David J. Wineland, David Hume, David Leibrandt
We describe an optical atomic clock based on quantum-logic spectroscopy of the 1S 0 3P 0 transition in 27Al + with a systematic uncertainty of 9.0 x 10-19 and a frequency stability of 1.2 X 10 -15/(T 1/2). A 25Mg + ion is simultaneously trapped with the

Analysis of Different Computational Techniques for Calculating the Polarizability Tensors of Stem Cells with Realistic Three-Dimensional Morphologies

July 15, 2019
Author(s)
Jack F. Douglas, Beatriz Betancourt, Somen Baidya, Ahmed M. Hassan, Waleed Al-Shaikhli, Edward J. Garboczi
In living systems, it is frequently stated that form follows function by virtue of evolutionary pressures on organism development, but in the study of how functions emerge at the cellular level, function often follows form. We study this chicken versus egg

Measurements of 25 Mg + and 27 Al + magnetic constants for improved ion clock accuracy

July 15, 2019
Author(s)
Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, Ethan Clements, Chin-wen Chou, Kyle Beloy, Will McGrew, Xiaogang Zhang, Robert J. Fasano, Daniele Nicolodi, Holly Leopardi, Tara Fortier, Scott Diddams, Andrew Ludlow, David J. Wineland, David Leibrandt, David Hume
We have measured the quadratic Zeeman coefficient for the 3P0 excited electronic state in 27Al+, C2=-71.944(24) MHz/T2 and the hyperfine constant of the 25Mg+ 2S1/2 ground electronic state, Ahfs = -596 254 250.981(45) Hz, with improved uncertainties. Both

Capture of Highly Charged Ions in a Pseudo-Hyperbolic Paul Trap

July 12, 2019
Author(s)
Joan M. Dreiling, Aung Naing, Joseph Tan, Joshua Hanson, Shannon Hoogerheide, Samuel Brewer
The confinement of ions in a radio-frequency (RF) trap (also known as a Paul trap) has proven to be advantageous in many applications. Typically, singly- or few-times-ionized atoms can be created in situ within the ion trap. Highly charged ions, on the

Single-Source Multiaxis Cold-Atom Interferometer in a Centimeter-Scale Cell

July 11, 2019
Author(s)
Yun Jhih Chen, Azure L. Hansen, Gregory W. Hoth, Eugene Ivanov, John E. Kitching, Elizabeth A. Donley
Using the technique of point source atom interferometry, we characterize the sensitivity of a multi-axis gyroscope based on free-space Raman interrogation of a single source of cold atoms in a glass vacuum cell. The instrument simultaneously measures the

NIST Time and Frequency Bulletin

July 8, 2019
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.

Photonic-crystal-reflector nano-resonators for Kerr-frequency combs

July 8, 2019
Author(s)
Su P. Yu, Hojoong Jung, Travis Briles, Kartik Srinivasan, Scott Papp
We demonstrate Kerr-frequency-comb generation with photonic-crystal-reflector (PCR) resonators, which is nanofabricated in a Fabry-Perot geometry. The group-velocity-dispersion (GVD) engineered photonic-crystal reflectors counteract the strong normal GVD

Cowan code: 50 years of growing impact on atomic physics

July 2, 2019
Author(s)
Alexander Kramida
The famous Cowan's book "The Theory of Atomic Structure and Spectra" published in 1981 and his suite of computer codes based on it continue to be highly influential in atomic physics and many other researchareas. As of September 2018, there are more than

Measurement of the Antineutrino Spectrum from 235U Fission at HFIR with PROSPECT

June 28, 2019
Author(s)
Hans Pieter Mumm, Denis E. Bergeron, Mark Tyra, Svetlana Nour, Jerome LaRosa
This Letter reports the first measurement of the 235U e energy spectrum by PROSPECT, the Precision Reactor Oscillation and Spectrum experiment, operating 7.9 m from the 85MWth highly-enriched uranium (HEU) High Flux Isotope Reactor. With a surface-based

High x-ray resolving power (up to 4000) utilizing asymmetric diffraction from a quartz transmission crystal measured in the 6 keV to 22 keV energy range

June 27, 2019
Author(s)
Lawrence T. Hudson, John F. Seely, Eric Galtier, Uri Feldman, Albert Henins
A Cauchois type spectrometer utilizing the (203) lattice planes at an oblique angle of 11.53o to the surface of a quartz transmission crystal recorded the Kα and Kβ spectral lines of six elements from Fe to Ag in the 6 keV to 22 keV energy range from a

Intrinsic spin currents in ferromagnets

June 24, 2019
Author(s)
Vivek P. Amin, Junwen Li, Mark D. Stiles, Paul M. Haney
First principles calculations show that electric fields applied to ferromagnets generate spin currents flowing perpendicularly to the electric field. Reduced symmetry in these ferromagnets enables a wide variety of such spin currents. However, the total

Quantum amplification of motion of a mechanical oscillator

June 21, 2019
Author(s)
Shaun C. Burd, Raghavendra Srinivas, John J. Bollinger, Andrew C. Wilson, David J. Wineland, Dietrich G. Leibfried, Daniel H. Slichter, David T. Allcock
Detection of the weakest forces in nature and the search for new physics demand increasingly sensitive measurements of the motion of mechanical oscillators. However, the attainable knowledge of an oscillator’s motion is limited by quantum fluctuations that

W -Band Vibrometer for Noncontact Thermoacoustic Imaging

June 20, 2019
Author(s)
Archita Hati, Craig Nelson
Noncontact thermoacoustic imaging (TAI) has several desirable characteristics for applications such as explosive detection in high-water-content media. In this letter, we report a detection technique using millimeter-wave interferometry based on sensitive

W-band Vibrometer for Non-contact Thermoacoustic Imaging

June 20, 2019
Author(s)
Archita Hati, Craig W. Nelson
Non-contact thermoacoustic imaging (TAI) has several desirable characteristics for applications such as explosive detection in high-water content media. In this paper, we report a detection technique using mm-wave interferometry based on sensitive phase

An Atom Probe Tomograph Incorporating a Wavelength-Tuneable Femtosecond-Pulsed Coherent Extreme Ultraviolet Light Source

June 19, 2019
Author(s)
Ann C. Chiaramonti Debay, Luis Miaja Avila, Paul T. Blanchard, David R. Diercks, Brian Gorman, Norman A. Sanford
Pulsed coherent extreme ultraviolet (EUV) radiation is a potential promising alternative to pulsed infra-red, visible, and near- ultraviolet laser sources for atom probe tomography. In addition to having the benefit of high absorption across the periodic

Coherently displaced oscillator quantum states of a single trapped atom

June 11, 2019
Author(s)
Katherine C. McCormick, Jonas Keller, David J. Wineland, Andrew C. Wilson, Dietrich Leibfried
Coherently displaced harmonic oscillator number states of a harmonically bound ion can be coupled to two internal states of the ion by a laser-induced motional sideband interaction. The internal states can subsequently be read out in a projective

Infrared electric-field sampled frequency comb spectroscopy

June 7, 2019
Author(s)
Abijith S. Kowligy, Henry R. Timmers, Alexander Lind, Ugaitz Elu, Flavio Caldas da Cruz, Peter Schunemann, Jens Biegert, Scott Diddams
Molecular spectroscopy in the mid-infrared portion of the electromagnetic spectrum (3--25 um) has been a cornerstone interdisciplinary analytical technique widely adapted across the biological, chemical, and physical sciences. Applications range from

Magneto-optic trap using a reversible, solid-state alkali-metal source

June 6, 2019
Author(s)
Songbai Kang, Kaitlin R. Moore, James P. McGilligan, R. Mott, A. Mis, C. Roper, Elizabeth A. Donley, John E. Kitching
Fast, reversible, and low-power alkali-atom sources are desirable in both tabletop and portable cold-atom sensors. Here we demonstrate a magneto-optic trap (MOT) formed in conjunction with a reversible solid state Rb reservoir in a vapor cell. The results
Displaying 876 - 900 of 2503
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