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Displaying 1501 - 1525 of 2503

A Low-Cost Time Transfer Receiver for Contributions to Coordinated Universal Time

November 6, 2014
Author(s)
Michael A. Lombardi, Andrew N. Novick, Victor S. Zhang
This paper describes a low-cost time transfer receiver that allows timing laboratories, including national metrology institutes and other designated institutions, to contribute data to the computation of Coordinated Universal Time (UTC). The time transfer

Fast transport of mixed-species ion chains within a Paul trap

November 6, 2014
Author(s)
Ryan S. Bowler, M. Palmer, John P. Gaebler, Dietrich G. Leibfried, J. G. Ceremuga
We investigate the dynamics of mixed-species ion crystals during transport between spatially distinct locations in a linear Paul trap in the diabatic regime. In a general mixed-species crystal, all degrees of freedom along the direction of transport are

Frequency Comb Generation in Superconducting Resonators

October 30, 2014
Author(s)
Robert P. Erickson, Michael Vissers, Martin O. Sandberg, Steven R. Jefferts, David P. Pappas
We have generated frequency combs spanning 0.5 to 20 GHz in superconducting λ=2 resonators at T ¼ 3 K. Thin films of niobium-titanium nitride enabled this development due to their low loss, high nonlinearity, low frequency dispersion, and high critical

Extended and Revised Analysis of Singly Ionized Tin: Sn II

October 28, 2014
Author(s)
K. Haris, Alexander Kramida, A. Tauheed
The electronic structure of singly ionized tin (Sn II) is partly a one-electron and partly a three-electron system with ground configuration 5s25p. The excited configurations are of the type 5s2nℓ in the one-electron part, and 5s5p2, 5p3 and 5s5pnℓ (nℓ =

A Cross-Benchmarking and Validation Initiative for Tokamak 3D Equilibrium Calculations

October 27, 2014
Author(s)
Geoffrey B. McFadden, Allan Reiman, Antoine Cerfon, E. Lazarus, S. Lazerson
We are pursuing a cross-benchmarking and validation initiative for tokamak 3D equilibrium calculations, with 11 codes participating: the linearized tokamak equilibrium codes IPEC and MARS-F,the time-dependent extended MHD codes M3D-C1, M3D, and NIMROD, the

Magnetoencephalography of Epilepsy with a Microfabricated Atomic Magnetrode

October 22, 2014
Author(s)
Svenja A. Knappe, Orang Alem, Alex M. Benison, Daniel S. Barth, John E. Kitching
We measured the magnetic signature of epileptiform discharges with high signal-to-noise ratio, using microfabricated atomic magnetometers based on laser spectroscopy of rubidium vapor and similar in size to scalp EEG electrodes. Sensitivity to neuronal

A geometric description of nonreciprocity in coupled two-mode systems

October 16, 2014
Author(s)
Leonardo M. Ranzani, Jose A. Aumentado
We explore the concept of nonreciprocity in coupled two-mode systems using a geometric mapping to the Poincaré sphere. From this perspective, we recast the requirements for nonreciprocity in terms of rotation and inversion symmetry arguments for the vector

Challenges of Irradiance-mode Spectral Response Measurements

October 16, 2014
Author(s)
Behrang H. Hamadani, John F. Roller, Brian P. Dougherty, Howard W. Yoon
Irradiance-mode spectral response measurements of solar cells are important because they provide a direct, reliable and accurate route for determination of the short circuit current (Isc) of solar cells under air mass 1.5 standard reference spectrum. In

High-Power and High-Linearity Photodetector Modules for Microwave Photonic Applications

October 15, 2014
Author(s)
Frederick N. Baynes, Efthymios Rouvalis, Xiaojun Xie, Qiugui Zhou, Franklyn J. Quinlan, Tara M. Fortier, Scott A. Diddams, Andreas G. Steffan, Andreas Beling, Joe C. Campbell
We demonstrate hermetically packaged InGaAs/InP photodetector modules for high performance microwave photonic applications. The devices employ an advanced photodiode epitaxial layer known as the modified uni-traveling carrier photodiode (MUTC-PD) with

Improvements in SIM Time Network and SIM Time Scale Performance

October 10, 2014
Author(s)
Michael A. Lombardi, J. Mauricio Lopez-Romero, Nelida Diaz-Munoz, E. de Carlos-Lopez, Marina Gertsvolf, Ricardo de Carvalho
We report recent results achieved within the Sistema Interamericano de Metrología (SIM) regarding the multinational cooperation program in the field of time and frequency metrology. We discuss the performance of the SIM Time Network (SIMTN) and the SIM

Phase-Sensitive Detection of Spin Pumping via the ac Inverse Spin Hall Effect

October 6, 2014
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Mathias A. Weiler
Sources of pure spin currents are a fundamental building block of spintronic devices. In ferromagnet/normal metal heterostructures, spin currents are generated at ferromagnetic resonance. This is known as spin pumping, where spin currents of both dc and ac

Universal scaling law for the flow of non-Newtonian colloidal suspension

October 1, 2014
Author(s)
Nicos Martys, William L. George, Maxime Liard, Pascal Hebraud, Didier Lootens
It has been observed that flow curves (viscosity vs shear-rate) of spherical non-colloidal particles suspended in a non-Newtonian fluid matrix can be rescaled so as to collapse onto the flow curve of the matrix fluid. This result is surprising given the

High-efficiency WSi superconducting nanowire single-photon detectors operating at 2.5 K

September 24, 2014
Author(s)
Varun B. Verma, Boris Korzh, Felix Bussieres, Robert D. Horansky, Adriana E. Lita, Francesco Marsili, Hugo Zbinden, Richard P. Mirin, Sae Woo Nam
We demonstrate that superconducting nanowire single photon detectors (SNSPDs) fabricated from amorphous WSi may be operated with > 75 % system detection efficiency at a temperature approaching seventy percent of the superconducting transition temperature

Photon-number uncertainty in a superconducting transition-edge sensor beyond resolved-photon-number determination

September 10, 2014
Author(s)
Zachary H. Levine, Boris L. Glebov, Alan L. Migdall, Thomas Gerrits, Brice R. Calkins, Adriana E. Lita, Sae Woo Nam
As part of an effort to extend fundamental single-photon measurements into the macroscopic regime, we explore how best to assign photon-number uncertainties to output waveforms of a superconducting Transition Edge Sensor (TES) and how those assignments

A 40 GHz Air-Dielectric Cavity Oscillator with Low Phase Modulation

September 1, 2014
Author(s)
Archita Hati, Craig W. Nelson, Billy F. Riddle, David A. Howe
We describe the design of a low-phase modulated (PM) noise, 40 GHz oscillator that uses a conventional air-dielectric cavity resonator as a frequency discriminator to improve the PM noise of a commercial 10 GHz dielectric resonator oscillator (DRO)

Optimization of Focused Ion Beam-Tomography for Superconducting Electronics

August 27, 2014
Author(s)
Aric W. Sanders, Anna E. Fox, Paul D. Dresselhaus, Alexandra Curtin
Superconducting electronics play an important role in quantum computation, ultra-low power electronics, voltage standards and magnetic sensors. Many of these applications rely on the microfabrication of superconducting circuits with multiple wiring layers

Engineering three-body interaction and Pfaffian states in circuit QED systems

August 18, 2014
Author(s)
Mohammad Hafezi, Prabin Adhikari, Jacob M. Taylor
We demonstrate a scheme to engineer the three-body interaction in circuit-QED systems by tuning a fluxonium qubit. Connecting such qubits in a square lattice and controlling the tunneling dynamics, in the form of a synthesized magnetic field, for the

Reducing oscillator PM noise from AM-PM noise correlaiton

August 14, 2014
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We present a new scheme for improving the phase modulated (PM) noise of an oscillator from correlation between amplitude modulated (AM) and PM noise. Experimental results of this correlation effect are presented. An improvement of almost 10 dB in the PM
Displaying 1501 - 1525 of 2503
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