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Displaying 1526 - 1550 of 2587

SI-Traceable Calibrations of Celestial Objects

May 14, 2015
Author(s)
Keith R. Lykke, Claire E. Cramer, John T. Woodward IV
Photometric calibration is currently the leading source of systematic uncertainty in supernova surveys that aim to determine the nature of dark energy. The bulk of this uncertainty is due to imperfect knowledge of the spectral energy distribution of stars

Confronting the Complexity of Commercial Carbon Nanotube Materials

May 13, 2015
Author(s)
Luis Fernando Vargas Lara, Jack F. Douglas
The morphology of commercially available carbon nanotube materials is often much more complex than the term “carbon nanotube” (CNT) would imply. Commercial CNT materials are typically composed of roughly spherical CNT domains having a highly ramified

Mid-Infrared Optical Frequency Combs based on Difference Frequency Generation for Dual-Comb Spectroscopy

May 10, 2015
Author(s)
Flavio Caldas da Cruz, Daniel I. Maser, Todd Johnson, Gabriel G. Ycas, Andrew M. Klose, Fabrizio R. Giorgetta, Ian R. Coddington, Nathan R. Newbury, Scott A. Diddams
Mid-infrared femtosecond optical frequency combs at 2.8 - 3.5 υm were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric

A New Modem for Two Way Satellite Time and Frequency Transfer

April 13, 2015
Author(s)
Shengkang Zhang, Xueyun Wang, Haifeng Wang, Hongbo Wang, Yuan Yuan, Keming Feng
Two Way Satellite Time Frequency Transfer (TWSTFT) is a highly precise time & frequency remote comparison technique, which is widely used in time metrology, satellite navigation, etc. Nowadays, most of the time metrology laboratories in Europe, America and

Bias Corrections in Primary Frequency Standards

April 13, 2015
Author(s)
Steven R. Jefferts, F Levi
Corrections to Primary Frequency Standards (PFS) or Secondary Frequency Standards (SFS) for offsets caused by various physical phenomena, e.g. Zeeman shifts or Blackbody radiation shifts, are typically corrected using formulae that contain “known”

Bias Corrections in Primary Frequency Standards

April 13, 2015
Author(s)
Thomas E. Parker, Thomas P. Heavner, Steven R. Jefferts
Primary frequency standards serve the function of calibrating the rate of International Atomic Time, TAI, and therefore play a critical role in the accuracy of the world's time. The Working Group on Primary and Secondary Frequency Standards, WGPSFS, is an

Long-Term Uncertainty in Time Transfer Using GPS and TWTFT Techniques

April 13, 2015
Author(s)
Victor S. Zhang, Thomas E. Parker, Jian Yao
The techniques of GPS time and frequency transfer (code based and carrier phase) and two-way satellite time and frequency transfer (TWSTFT) are widely used in remote clock comparison and in the computation of International Atomic Time (TAI). Many timing

Comparison of Two Continuous GPS Carrier-Phase Time Transfer Techniques

April 12, 2015
Author(s)
Jian Yao, Skakun Ivan, Zhiheng Jiang, Judah Levine
Global Positioning System (GPS) carrier-phase (CP) time transfer, as a widely accepted high-precision time transfer method, frequently shows a data-batch boundary discontinuity of up to 1 ns, because of the inconsistency of the phase ambiguities between

Practical Limitations of NTP Time Transfer

April 12, 2015
Author(s)
Andrew N. Novick, Michael A. Lombardi
The Network Time Protocol (NTP) is commonly utilized to synchronize computer clocks in packet-switched, wide area networks (WANs) such as the public Internet. The delay asymmetry in WANs, often due to inconsistent routing and/or bandwidth saturation, is

Time Signals Converging within Cyber-Physical Systems

April 12, 2015
Author(s)
Marc A. Weiss, Sundeep Chandhoke, Hugh Melvin
Time is central to predicting, measuring and controlling properties of the physical world, and is one of the most important constraints distinguishing Cyber-Physical Systems (CPS) from distributed computing in general. However mixing the cyber and the

Light shifts in a pulsed cold-atom coherent-population-trapping clock

April 10, 2015
Author(s)
Eric M. Blanshan, Elizabeth A. Donley, John E. Kitching
Field-grade atomic clocks capable of primary standard performance in compact physics packages would be of significant value in a variety of applications. A cold-atom coherent population trapping clock featuring laser-cooled 87Rb atoms and pulsed Ramsey

Exponential scaling of clock stability with atom number

March 28, 2015
Author(s)
Till P. Rosenband, David R. Leibrandt
In trapped-atom clocks, the primary source of decoherence is often the phase noise of the oscillator. In this case, it is theoretically possible to derive exponential performance gains by combining several atomic ensembles. For example, M ensembles of N

Early observations of macroscopic quantum jumps in single atoms

March 25, 2015
Author(s)
Wayne M. Itano, James C. Bergquist, David J. Wineland
The observation of intermittent fluorescence of a single atomic ion, a phenomenon better known as 'macroscopic quantum jumps,' was an important early scientific application of the three-dimensional rf quadrupole (Paul) trap. The prediction of the

Update on the MiniCLEAN Dark Matter Experiment

March 24, 2015
Author(s)
Kevin J. Coakley, K. Rielage, M. Akashi-Ronquest, M. Bodmer, R. Bourque, B. Buck, A. Butcher, T. Caldwell, Y. Chen, F. A. Duncan, E. Flores, J. A. Formaggio, D. Glaster, F. Giuliani, M. Gold, E. Grace, J. Griego, N. Guerrero, V. Guiseppe, R. Henning, A. Hime, S. Jaditz, C. Kachulis, E. Kearns, J. Kelsey, J. R. Klein, A. Latorre, I. Lawson, O. Li, P. Liimatainen, S. Linden, F. Lopez, K. McFarlane, D. N. McKinsey, S. MacMullin, A. Mastbaum, D.-M. Mei, J. Monroe, J. A. Nikkel, J. Oertel, G. D. Orebi Gann, K. Palladino, G. Perumpilly, L. Rodriguez, R. Schnee, S. Seibert, J. Walding, B. Wang, J. Wang, C. Zhang
The direct search for dark matter is entering a period of increased sensitivity to the hypothetical Weakly Interacting Massive Particle (WIMP). One such technology that is being examined is a scintillationonly noble liquid experiment, MiniCLEAN. MiniCLEAN

High-Fidelity, Weak-Light Polarization Gate Using Room-Temperature Atomic Vapor

March 18, 2015
Author(s)
Lu Deng, Edward W. Hagley, Runbing Li, Chengjie Zhu
Using a polarization-selective-Kerr-phase-shift technique we demonstrate a fast, all-optical, high-fidelity polarization gate in a room-temperature atomic medium. By writing a pi-phase shift to one selected circularly-polarized component of a linearly

Light-wave mixing and scattering with quantum gases

March 18, 2015
Author(s)
Lu Deng, Edward W. Hagley, C.J. Zhu
We show that optical processes originating from elementary excitations with dominant collective atomic recoil motion in a quantum gas can profoundly change many nonlinear optical processes routinely observed in a normal gas. Not only multi-photon wave

Development and evaluation of interface-stabilized and reactive-sputtered oxide-capped multilayers for EUV lithography

March 16, 2015
Author(s)
Michael Kriese, Jim Rodriguez, Gary Fournier, Steven Grantham, Shannon B. Hill, John J. Curry, Charles S. Tarrio, Yuriy Platonov
A critical component of high-performance EUV lithography source optics is the reflecting multilayer coating. The ideal multilayer will have both high reflectance and high stability to thermal load. Additionally the capping layers must provide resistance to

Dual-microcavity narrow-linewidth Brillouin laser

March 5, 2015
Author(s)
William Loh, Adam A. Green, Frederick N. Baynes, Daniel C. Cole, Franklyn J. Quinlan, Hansuek Lee, Kerry J. Vahala, Scott A. Diddams
The tunable narrow-linewidth laser is a revolutionary metrology tool that is critical in precision spectroscopy and the determination of fundamental physical constants, displacement measurements at the 10 -20 level, and the development of the most advanced

Analysis of coincidence-time loopholes in experimental Bell tests

March 4, 2015
Author(s)
B. G. Christensen, A. Hill, P. G. Kwiat, Emanuel Knill, Sae Woo Nam, Kevin Coakley, Scott Glancy, Krister Shalm, Y. Zhang
We apply a distance-based Bell-test analysis method ["Bell inequalities for continuously emitting sources" E. Knill et al. arXiv:14097732 (2014)] to three experimental data sets where conventional analyses failed or required additional assumptions. The
Displaying 1526 - 1550 of 2587
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