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Physics

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Displaying 1701 - 1725 of 2516

New Version: Grasp2K Relativistic Atomic Structure Package

February 19, 2013
Author(s)
P. Jonsson, G. Gaigalas, J Bieron, Charlotte F. Fischer, I. P. Grant
A revised version of Grasp2K [P. Jonsson, X. He, C. Froese Fischer, and I.P. Grant, Comput. Phys. Commun. 177 (2007) 597] is presented. It supports earlier non-block and block versions of codes as well as a new block version in which the njgraf library

A One-Kilogram Quartz Resonator as a Mass Standard

February 1, 2013
Author(s)
David A. Howe, J Vig
The unit of mass, the kilogram, is the last remaining SI base unit defined by an artifact” [1]. This artifact, the primary mass standard, suffers from long term instabilities that are neither well understood, nor easily monitored [2]. A mass standard

Techniques for microwave near-field quantum control of trapped ions

January 31, 2013
Author(s)
Ulrich J. Warring, C. Ospelkaus, Yves Colombe, Kenton R. Brown, Jason Amini, M Carsjens, Dietrich G. Leibfried, David J. Wineland
In Ospelkaus et al. [Nature 476, 181 (2011)] a microwave near-field quantum control of spin and motional degrees of freedom of one and two 25Mg+ ions enabled two-ion entanglement. In this report, we extend on the description of the experimental setup and

Tunnel junction sensors for HCI-surface measurements at low kinetic energies

January 25, 2013
Author(s)
Joshua M. Pomeroy, Russell E. Lake
In recent years, we have developed and deployed the capability to make and use tunnel junctions sensors (TJS) as extremely sensitive tools for the measurement of surface nanofeatures created by particle surface interactions. Highly charged ion (HCI)

Improvements in silicon oxide dielectric loss for superconducting microwave detector circuits

January 24, 2013
Author(s)
Dale Li, Jason Austermann, James A. Beall, Daniel T. Becker, Hsiao-Mei Cho, Anna E. Fox, Nils Halverson, Jason Henning, Gene C. Hilton, Johannes Hubmayr, Jeffrey L. Van Lanen, John P. Nibarger, Michael D. Niemack, Kent D. Irwin
Dielectric loss in low-temperature superconducting integrated circuits can cause lower overall efficiency, particularly in the 90 to 220 GHz regime. We present a method to tune the dielectric loss for silicon oxide deposited by plasma-enhanced chemical

NIST Time and Frequency Bulletin

January 18, 2013
Author(s)
Petrina C. Potts
The Time and Frequency Bulletin provides information on performance of time scales and a varieth of broadcasts (and related information) to users of the NIST services.

Standardization of Broadband UV Measurements

January 1, 2013
Author(s)
George P. Eppeldauer
The CIE standardized rectangular-shape UV response functions can be realized only with large spectral mismatch errors. The spectral power-distribution of UV sources is not standardized. Accordingly, the readings of different types of UV meters, even if

The spectrum of Fe II

January 1, 2013
Author(s)
Gillian Nave, S Johansson
The spectrum of singly-ionized iron (Fe II) has been recorded using high-resolution Fourier transform and grating spectroscopy over the wavelength range 900 Å to 5.5 μm. The spectra were recorded in high-current continuous and pulsed hollow cathode

Time Transfer Using a Satellite Navigation System

January 1, 2013
Author(s)
Judah Levine
Article does not have an abstract. It was solicited by the editors of the yearbook and was written based on their detailed comments about the topics to be covered, the technical detail, etc. It is intended for high-school students and contains material

Hybrid Electro-Optically Modulated Microcombs

December 28, 2012
Author(s)
Pascal P. Del'Haye, Scott B. Papp, Scott A. Diddams
Optical frequency combs based on mode-locked lasers have proven to be invaluable tools for a wide range of applications in precision spectroscopy and metrology. Recently, a novel principle of optical frequency comb generation in whispering gallery mode

Ultrafast element-specific magnetization Dynamics of complex magnetic materials on a table-top

December 21, 2012
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Chan La-O-Vorakiat, Henry C. Kapteyn, Margaret M. Murnane, Stefan Mathias, Roman Adam, Patrik Grychtol, Martin Aeschlimann, Claus M. Schneider, Emrah Turgut, Dennis Rudolf
We review recent progress in femtosecond magnetization dynamics probed by extreme ultraviolet pulses from high-harmonic generation. In a transverse magneto-optical Kerr geometry, we establish an ultrafast, element-specific experimental capability - on a

A Low-Power, High-Sensitivity Micromachined Optical Magnetometer

December 11, 2012
Author(s)
Rahul R. Mhaskar, Svenja A. Knappe, John E. Kitching
We demonstrate a fiber-optically coupled optical magnetometer based on a microfabricated 87Rb vapor cell in a micromachined silicon sensor head. The cell is optically heated with light at 1.5 mm brought to the cell through an optical fiber and absorbed by

Single bead detection with a NMR micro capillary probe

December 6, 2012
Author(s)
Yoshihiro Nakashima, Michael A. Boss, Stephen E. Russek, John M. Moreland
We have developed a nuclear magnetic resonance (NMR) microcapillary probe for the detection of single magnetic microbeads. The geometry of the probe has been optimized so that the signal from the background water has a similar magnitude compared to the

Phase-Noise Measurement System for the Terahertz-Band

November 30, 2012
Author(s)
Jason A. DeSalvo, Archita Hati, Craig W. Nelson, David A. Howe
We present initial phase noise measurements in support of terahertz electronics, in the frequency range generally regarded as 0.1 to 10 THz. Using digital phase noise measurement techniques and an even-harmonic mixer, we achieve a phase noise measurement

Determination of the 5d6s 3D1 state lifetime and blackbody radiation clock shift in Yb

November 29, 2012
Author(s)
Kyle P. Beloy, Jeffrey A. Sherman, Nathan D. Lemke, Nathan M. Hinkley, Christopher W. Oates, Andrew D. Ludlow
The Stark shift of the ytterbium optical clock transition due to room temperature blackbody radiation is dominated by a static Stark effect, which was recently measured to high accuracy [J. A. Sherman et al., Phys. Rev. Lett. 108, 153002 (2012)]. However

High Bandwidth Optical Magnetometer

November 28, 2012
Author(s)
Ricardo Jimenez Martinez, William C. Griffith, Svenja A. Knappe, John E. Kitching, Mark Prouty
We demonstrate a scalar 87Rb optical magnetometer that retains magnetic eld sensitivities below 10 pT/√Hz over 3dB bandwidths of 10 kHz in an ambient eld Bo = 11.4 microT and using a measurement volume of 1 mm 3. The magnetometer operates at high atomic

A COLD-ATOM CLOCK BASED ON COHERENT POPULATION TRAPPING

November 26, 2012
Author(s)
Elizabeth A. Donley, Francois-Xavier R. Esnault, Eric M. Blanshan, John E. Kitching
A compact cold-atom clock based on coherent population trapping is being developed. The clock aims to ultimately achieve a timing uncertainty of a few nanoseconds per day. Here we present an initial evaluation of the three main systematic frequency shifts

Enabling accurate differential calibration of modern GPS receivers

November 26, 2012
Author(s)
Stefania Romisch, Victor S. Zhang, Thomas E. Parker, Steven R. Jefferts
The difference between the local time reference and a GNSS receiver's internal time base is an essential contributor to the calibration of that receiver when used as a timing device. In the past, in the absence of a PPS output signal provided by the

GPS Carrier-Phase Time Transfer Boundary Discontinuity Investigation

November 26, 2012
Author(s)
Jian Yao, Judah Levine
We report on a study of the carrier-phase time transfer boundary discontinuity by the use of the precise point positioning (PPP) technique. Carrier-phase time transfer is first compared with two-way satellite time and frequency transfer (TWSTFT) between

In Search of a New Primary GPS Receiver for NIST

November 26, 2012
Author(s)
Marc A. Weiss
A previous publication showed problems with the current NIST Time and Frequency Division primary GPS receiver [1] when used for Precise Point Positioning (PPP)-based carrier phase time transfer. We confirm that, for this receiver, boundary discontinuities
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