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Displaying 901 - 925 of 2466

Metrological and legal traceability of time signals

March 1, 2019
Author(s)
Michael A. Lombardi, Demetrios Matsakis, Judah Levine
Metrological traceability requires an unbroken chain of calibrations that relate to a reference, with each calibration having a documented measurement uncertainty. In the field of time and frequency metrology, the desired reference is usually Coordinated

Switchable detector array scheme to reduce the effect of single-photon detector's deadtime in a multi-bit/photon quantum link

February 25, 2019
Author(s)
Cong Liu, YONGXIONG Ren, Jiapeng Zhao, MOHAMMAD MIRHOSSEINI, SEYED RAFSANJANI, GUODONG XIE, Kai Pang, Zhe Zhao, Long Li, Joshua Bienfang, Alan L. Migdall, Todd Brun, Moshe Tur, Robert Boyd, Alan Wilner
We explore the use of a switchable single-photon detector (SPD) array to reduce the effect of individual SPDs' deadtime for a multi-bit/photon quantum link such as M-orbital-angular-momentum (OAM)-encoded one. Our method uses 􀡺 SPDs with a controllable 􀡹 ×

EBIT Observation of Low Charge State Ar Dielectronic Recombination Features Near the Unknown Faint X-Ray Feature Found in the Stacked Spectrum of Galaxy Clusters

February 20, 2019
Author(s)
A. Gall, A. Foster, R. Silwal, Joan M. Dreiling, A. Borovik, E. Kilgore, M. Ajello, John Gillaspy, Yuri Ralchenko, Endre Takacs
Motivated by possible atomic origins of the unidentified emission line detected at 3.55 keV - 3.57 keV in a stacked spectrum of galaxy clusters (Bulbul et al. 2014), an electron beam ion trap (EBIT) was used to investigate resonant dielectronic

Modeling near ground-state cooling of two-dimensional ion crystals in a Penning trap using electromagnetically induced transparency

February 7, 2019
Author(s)
Athreya Shankar, Elena Jordan, Kevin Gilmore, Arghavan Safavi-Naini, John J. Bollinger, Murray Holland
Penning traps, with their ability to control planar crystals of tens to hundreds of ions, are versatile quantum simulators. Thermal occupations of the motional drumhead modes, transverse to the plane of the ion crystal, degrade the quality of quantum

Near ground-state cooling of two-dimensional trapped-ion crystals with more than 100 ions

February 7, 2019
Author(s)
Judith Elena Jordan, Kevin A. Gilmore, Athreya Shankar, Arghavan Safari-Naini, Justin G. Bohnet, Murray Holland, John J. Bollinger
We study, both experimentally and theoretically, electromagnetically induced transparency cooling of the axial drumhead modes of 2-dimensional arrays with up to N 190 Be+ ions stored in a Penning trap. Substantial sub-Doppler cooling is observed for all N

Calculation of the impulse response and phase noise of a high-current photodetector using the drift-diffusion equations

February 4, 2019
Author(s)
Franklyn Quinlan, Seyed Ehsan Jamali Mahabadi, Shaokang Wang, Thomas F. Carruthers, Curtis R. Menyuk, Meredith N. Hutchinson, Jason D. McKinney, Keith J. Williams
We describe a procedure to calculate the impulse response and phase noise of high-current photodetectors using the drift-diffusion equations while avoiding computationally expensive Monte Carlo simulations. We apply this procedure to a modified uni

Field-Polarization Sensitivity in rf Atomic Magnetometers

February 4, 2019
Author(s)
Vladislav P. Gerginov
We demonstrate the sensitivity of an optically-pumped atomic RF magnetometer to the polarization state of the detected RF magnetic field, and measure 33 dB difference in amplitude sensitivity for opposite circular field polarizations. This sensitivity

First observation with global network of optical atomic clocks aimed for a dark matter detection

January 30, 2019
Author(s)
P. Wcislo, P. Ablewski, Kyle Beloy, S. Bilicki, M. Bober, Roger Brown, Robert J. Fasano, R. Ciurylo, H. Hachisu, T. Ido, J. Lodewyck, Andrew Ludlow, Will McGrew, P. Morzynski, Daniele Nicolodi, Marco Schioppo, M. Sekido, R. Le Targat, P. Wolf, Xiaogang Zhang, B. Zjawin, M. Zawada
We report on the first earth-scale quantum sensor network based on optical atomic clocks aimed at dark matter (DM) detection. Exploiting differences in the susceptibilities to the fine- structure constant of essential parts of an optical atomic clock, i.e

Rethinking Timekeeping for Modern IT Solutions

January 28, 2019
Author(s)
Son VoBa, Charles L. Ulland, Michael A. Lombardi, Arno Lentfer
Advances in processor performance and virtualization technologies, together with complexities of operating systems (OS) and software defined networking, have outpaced legacy network-based solutions for keeping system clocks accurate across geographic

The quantum Zeno paradox, 42 years on

January 25, 2019
Author(s)
Wayne M. Itano
The term 'quantum Zeno paradox' or 'quantum Zeno effect' refers to the slowing down of the evolution of a quantum system as it is observed more and more frequently. In 1977, Misra and Sudarshan gave a theoretical demonstration of its existence. There has

Trapped Ion Quantum Information Processing with Squeezed Phonons

January 24, 2019
Author(s)
Wenchao Ge, Brian Sawyer, Joseph W. Britton, Kurt Jacobs, John Bollinger, Michael Foss-Feig
Trapped ions offer a pristine platform for quantum computation and simulation, but improving their coherence remains a crucial challenge. Here, we propose and analyze a new strategy to enhance the coherent interactions in trapped-ion systems via parametric

Artificial gauge fields with ultracold neutral atoms

January 1, 2019
Author(s)
Ian B. Spielman, Victor Galitski, Gediminas Juzeliunas
Gauge fields are ubiquitous in nature. In the context of quantum electrodynamics, you may be familiar with the photon, that represents the dynamical gauge field mediating electromagnetic forces. In fact all elementary interactions are mediated by gauge

Nonlinear Response of Silicon Solar Cells

January 1, 2019
Author(s)
Behrang H. Hamadani, Andrew M. Shore, Howard W. Yoon, Mark Campanelli
We used an LED-array-based combinatorial flux addition method to explore the wavelength and the intensity-dependence of the spectral responsivity in silicon solar cells. Many types of silicon cells, whether mono- or multi-crystalline type, exhibit notable

Chip-scale atomic diffractive optical elements

December 31, 2018
Author(s)
Liron Stern, Douglas G. Bopp, Susan A. Schima, Vincent N. Maurice, John E. Kitching
Atomic systems have long provided a useful material platform with unique quantum properties. The efficient light-matter interaction in atomic vapors has led to numerous seminal scientific achievements including accurate and precise metrology 1-3 and

Evidence for multiple mechanisms underlying surface-electric field noise in ion traps

December 27, 2018
Author(s)
J. A. Sedlacek, J. Stuart, Daniel Slichter, C. D. Bruzewicz, R. McConnell, J. M. Sage, J. Chiaverini
Energetic ion bombardment, or ion milling, of ion-trap electrode surfaces has previously been shown to reduce electric-field noise, a limit to quantum-logic gate fidelity, generated by the surface. Here, using motional heating of a single trapped strontium

The Metrological Basis for MOBY

December 20, 2018
Author(s)
Bettye C. Johnson
The Marine Optical BuoY (MOBY) is a primary source of data for System Vicarious Calibration (SVC) of ocean color satellite sensors. I will present brief introduction to SVC followed by a short history of MOBY and the main features of its instrumentation

Time Synchronization over a Free-Space Optical Communication Channel

December 20, 2018
Author(s)
Isaac H. Khader, Laura C. Sinclair, William C. Swann, Hugo Bergeron, Nathan R. Newbury, Jean-Daniel Deschenes
Free space optical (FSO) communication channels are typically used to transmit high-speed data between sites over the air. Here we repurpose an FSO digital communication system and use it directly for two-way time transfer. We demonstrate real-time
Displaying 901 - 925 of 2466
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