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Physics

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Displaying 2051 - 2075 of 2493

Vibration-induced PM and AM noise in microwave components

October 1, 2009
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
The performance of microwave components is sensitive to vibrations to some extent. Among them, microwave cables and connectors, bandpass filters, mechanical phase shifters and some non-linear components are the most sensitive. The local oscillator is one

Ultra-cold mechanical resonators coupled to atoms in an optical lattice

September 17, 2009
Author(s)
Andrew Geraci, John E. Kitching
We propose an experiment utilizing an array of cooled micro-cantilevers coupled to a sample of ultra-cold atoms trapped near a micro-fabricated surface. The cantilevers allow individual lattice site addressing for atomic state control and readout, and

Complete Methods Set for Scalable Ion Trap Quanum Information Processing

September 4, 2009
Author(s)
Jonathan Home, David Hanneke, John D. Jost, Jason Amini, Dietrich G. Leibfried, David J. Wineland
Building a quantum information processor capable of outperforming classical devices will require many quantum bits (qubits) and very large numbers of logical operations \cite{05Knill}. A key requirement is the faithful transport of qubits throughout the

Energy Decay in Josephson Qubits from Non-equilibrium Quasiparticles

August 26, 2009
Author(s)
Jose A. Aumentado, John M. Martinis, M Ansmann
We calculate the energy decay rate of Josephson qubits and superconducting resonators from non-equilibrium quasiparticles. The decay rates from experiments are shown to be consistent with our predictions based on a prior measurement of the quasiparticle

Treatment of Uncertainties in Radiation Dosimetry

August 18, 2009
Author(s)
Michael G. Mitch, Larry DeWerd, Ronaldo Minniti, J Williamson
When one perform a physical measurement or a Monte Carlo simulation and obtains a numerical result, the following questions may be asked. How accurate is the result? Is the measurement or simulation method of high quality? Can the result be meaningfully

Temperature analysis of low-expansion Fabry-Perot cavities

August 17, 2009
Author(s)
Richard W. Fox
A model of the temperature response of low-expansion glass Fabry-Perot cavities that includes structural distortion at the contacted mirrors compares well to frequency measurements of different cavities built with the same spacer. The path elongation at

Conversion of laser optical rotation noise in cesium vapor

August 15, 2009
Author(s)
Ricardo Jimenez Martinez, Svenja A. Knappe, William C. Griffith, John E. Kitching
We have studied the noise in the optical rotation of a linearly polarized laser beam transmitted through a spin-polarized 133Cs vapor as a function of its frequency detuning from the optical resonance. Our measurements demonstrate the direct conversion of

A Spin-1/2 Optical Lattice Clock

August 7, 2009
Author(s)
Nathan D. Lemke, Andrew D. Ludlow, Zeb Barber, Tara M. Fortier, Scott A. Diddams, Yanyi Jiang, Steven R. Jefferts, Thomas P. Heavner, Thomas E. Parker, Christopher W. Oates
We experimentally investigate an optical clock based on 171Yb (I = 1/2) atoms confined in an optical lattice. We have evaluated all known frequency shifts to the clock transition, including the density-dependent collision shift, with an uncertainty of 0.19

Establishment of the SIM Time Scale

August 1, 2009
Author(s)
J. Mauricio Lopez-Romero, N. Munoz, Michael A. Lombardi
The SIM time and frequency metrology working group has developed a comparison network for the Americas, with the goals of improving metrology in the SIM region and to allow as many countries as possible to participate in the network. As of May 2008, ten

Stylus ion trap for enhanced access and sensing

August 1, 2009
Author(s)
Robert Maiwald, Gerd Leuchs, Dietrich Leibfried, Joseph W. Britton, James C. Bergquist, David J. Wineland
We experimentally characterized a novel radio-frequency (rf) ion trap geometry formed by two concentric cylinders over a ground plane. These traps allow for optical and physical access over more than 2 pi solid angle reaching 91% and 96% of 4 respectively

Optimize Noise Filtration through Dynamical Decoupling

July 24, 2009
Author(s)
Hermann Uys, Michael J. Biercuk, John J. Bollinger
One approach to maintaining phase coherence of qubits through dynamical decoupling consists of applying a sequence of Hahn spin-echo pulses. Recent studies have shown that, in certain noise environments, judicious choice of the delay times between these

The-Final-State Symmetry of Na 1s Core-shell Excitons in NaCl and NaF

July 8, 2009
Author(s)
Eric L. Shirley, K. P. Nagle, G T. Seidler, T. T. Fister, J. A. Bradley, F. C. Brown
We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering (NRIXS) from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum transfer-dependence (q-dependence)

Optical Lattice-Based Addressing and Control of Long-Lived Neutral-Atom Qubits

July 6, 2009
Author(s)
Nathan Lundblad, J Obrecht, Ian B. Spielman, James V. Porto
The establishment of a scalable, addressable, and long-lived scheme for quantum computing would be a scientific watershed, harnessing the laws of quantum physics to solve classically intractable problems. Many proposed computational platforms are driven by

Experimental Uhrig Dynamical Decoupling Using Trapped Ions

June 25, 2009
Author(s)
Michael J. Biercuk, Hermann Uys, Aaron Vandevender, Nobuyasu Shiga, Wayne M. Itano, John J. Bollinger
We present a detailed experimental study of the Uhrig Dynamical Decoupling (UDD) sequence in a variety of noise environments. Our qubit system consists of a crystalline array of 9Be + ions confined in a Penning trap. We use an electron-spin-flip transition

Rubidium Vapor Cell with Integrated Bragg Reflectors for Compact Atomic MEMS

June 9, 2009
Author(s)
Maximillian Perez, Uyen Nguyen, Svenja A. Knappe, Elizabeth Donley, John Kitching, A Shkel
This paper reports on a method for improving the optical efficiency of micro-machined reflectors integrated in rubidium vapor cells for application in atomic MEMS sensors. A hybrid bulk micromachining and multilayer PECVD thin film process is used to form

Frequency Measurements of Al+ and Hg+ Optical Standards

June 8, 2009
Author(s)
Wayne M. Itano, James C. Bergquist, Till P. Rosenband, David J. Wineland, David Hume, Chin-wen Chou, Steven R. Jefferts, Thomas P. Heavner, Tom Parker, Scott Diddams, Tara Fortier
Frequency standards based on narrow optical transitions in 27Al+ and 199Hg+ ions have been developed at NIST. Both standards have absolute reproducibilities of a few parts in 10 17. This is about an order of magnitude better than the fractional uncertainty

Entangled Mechanical Oscillators

June 4, 2009
Author(s)
John D. Jost, Jonathan Home, Jason Amini, David Hanneke, R. Ozeri, Christopher Langer, John J. Bollinger, Dietrich G. Leibfried, David J. Wineland
Quantum mechanics describes the state and evolution of isolated systems, where entangled and superposition states can be created. Its application to large systems led Schr dinger to posit his famous cat, which exists in a superposition of alive and dead

Supercontinuum Sources for Metrology

June 2, 2009
Author(s)
John T. Woodward IV, Allan W. Smith, Colleen A. Jenkins, Chungsan Lin, Steven W. Brown, Keith R. Lykke
Supercontinuum (SC) sources are novel laser-based sources that generate a broad, white-light continuum in single mode photonic crystal fibers. Currently, up to 6 W of optical power is available, spanning the spectral range from 460 nm to 2500 nm. Advances

Extension of the NIST tristimulus colorimeter for solid-state light source measurements

May 29, 2009
Author(s)
George P. Eppeldauer, Carl C. Miller, Thomas C. Larason, Yoshihiro Ohno
In order to obtain improved color measurement uncertainties for solid state light (SSL) sources, the second generation tristimulus colorimeter of NIST has been extended with a fifth channel to perform efficient matrix corrections for the spectral mismatch

A deep-UV optical frequency comb at 205 nm

May 25, 2009
Author(s)
Scott A. Diddams, E Peters, P Fendel, S Reinhardt, T W. Hansch, T Udem
By frequency quadrupling a picosecond pulse train from a Ti:sapphire laser at 820 nm we generate a frequency comb at 205 nm with nearly bandwidth-limited pulses. The nonlinear frequency conversion is accomplished by two successive frequency doubling stages

Observing the Quantization of Zero Mass Carriers in Graphene

May 15, 2009
Author(s)
Joseph A. Stroscio, Gregory M. Rutter, D. L. Miller, K. Kubista, W. A. de Heer, Phillip N. First
Application of a magnetic field to conductors causes the charge carriers to circulate in cyclotron orbits with quantized energies called Landau levels (LLs). These are equally spaced in normal metals and two-dimensional electron gases. In graphene, however

Time domain measurement of phase noise in a spin torque oscillator

May 13, 2009
Author(s)
Mark W. Keller, Anthony B. Kos, Thomas J. Silva, William H. Rippard, Matthew R. Pufall
We measure phase noise from the zero crossings of the voltage vs. time waveform of a spin torque nanocontact oscillating in a vortex mode. The power spectrum of the phase noise varies with Fourier frequency f as 1/f 2, consistent with frequency
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