U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Physics

Search Publications

Search Title, Abstract, Conference, Citation, Keyword or Author
  • Published Date
Displaying 1701 - 1725 of 2574

Quantum simulation and many-body physics with hundreds of trapped ions

September 14, 2013
Author(s)
John J. Bollinger, Joseph W. Britton, Brian C. Sawyer
By employing forces that depend on the internal electronic state (or spin) of an atomic ion, the Coulomb potential energy of a trapped ion crystal can be modified in a spin-dependent way to mimic effective quantum spin Hamiltonians. We use simple models to

An atomic clock with 10 -18 instability

September 13, 2013
Author(s)
Andrew D. Ludlow, Nathan M. Hinkley, Jeffrey A. Sherman, Nate B. Phillips, Marco Schioppo, Nathan D. Lemke, Kyle P. Beloy, M Pizzocaro, Christopher W. Oates
Atomic clocks have been transformational in science and technology, leading to innovations such as global positioning, advanced communications, and tests of fundamental constant variation. Next-generation optical atomic clocks can extend the capability of

A Study of the Diurnal in the Transatlantic TWSTFT Difference

September 7, 2013
Author(s)
Victor S. Zhang, Thomas E. Parker
The daily variation (diurnal) in the two-way satellite time and frequency transfer (TWSTFT) difference is one of the most significant instabilities of the TWSTFT technique. The diurnal comes from the daily delay change of the TWSTFT signal paths. In recent

Reply to "Comment on: 'Ultrafast Demagnetization Measurements Using Extreme Ultraviolet Light: Comparison of Electronic and Magnetic Contributions'"

September 4, 2013
Author(s)
Justin Shaw, Thomas J. Silva, Hans Nembach, Emrah Turgut, Patrik Grychtol, Chan La-O-Vorakiat, Henry C. Kapteyn, Margaret M. Murnane, Stefan Mathias, Martin Aeschlimann, Claus Schneider, Daniel E. Adams
In the following, we show that the conclusions of our article titled "Ultrafast Demagnetization Measurements Using Extreme Ultraviolet Light: Comparison of Electronic and Magnetic Contributions" are correct. The Comment of Vodungbo et al. argues that a

State-of-the-Art RF Signal Generation From Optical Frequency Division

September 2, 2013
Author(s)
Archita Hati, Craig W. Nelson, Corey A. Barnes, Danielle G. Lirette, Tara M. Fortier, Franklyn J. Quinlan, Jason A. DeSalvo, Andrew D. Ludlow, Till P. Rosenband, Scott A. Diddams, David A. Howe
We present the design of a novel, ultra-low phase-noise frequency synthesizer implemented with extremely low noise regenerative frequency dividers. This synthesizer generates eight outputs viz. 1.6 GHz, 320 MHz, 160 MHz, 80 MHz, 40 MHz, 20 MHz, 10 MHz and

Detection of l-C3H+ in Sgr B2(N) and Sgr B2(OH) and Refinement of its Spectroscopic Constants via the Publicly Available PRIMOS Survey and the Barry E. Turner Legacy Survey

September 1, 2013
Author(s)
Francis J. Lovas, Brett A. McGuire, P. B. Carroll, Ryan A. Loomis, Geoffery A. Blake, Jan M. Hollis, Phillip R. Jewell, Anthony J. Remijan
Pety et al. (2012) recently reported the detection and assignment of l-C3H+ in the Horsehead nebula. Here, we expand that analysis to include the J = 1 - 0 and J = 2 - 1 transitions of l-C3H+ observed in absorption towards Sgr B2(N) in data from the

Giant Secondary Grain Growth in Cu Films on Sapphire

August 1, 2013
Author(s)
David L. Miller, Mark W. Keller, Justin Shaw, Katherine P. Rice, Robert Keller, Kyle M. Diederichsen
Single crystal metal films on insulating substrates are attractive for microelectronics and other applications, but they are difficult to achieve on macroscopic length scales. The conventional approach to obtaining such films is epitaxial growth at high

Relaxation timescales and decay of correlations in a long-range interacting quantum simulator

August 1, 2013
Author(s)
John J. Bollinger, Mauritz van den Worm, Rytis Paskauskas, Brian C. Sawyer, Michael Kastner
When a physical system is coupled to a heat bath, one expects to observe thermalization to an equilibrium state whose temperature is determined by the bath properties. For an isolated many-body system, i.e. in the absence of a heat bath, the situation is

Cancellation of Doppler Shifts in a Cold-Atom CPT Clock

July 25, 2013
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 (CPT) is being developed. Long-term goals for the clock include achieving a fractional frequency accuracy of 1x10 -13 in a package of less than 10 cm 3 in volume. Here we present an overview

Why there is no noon-midnight red shift in the GPS

July 24, 2013
Author(s)
Neil Ashby, Marc A. Weiss
Although the effects of solar and lunar gravitational potentials on the frequencies of orbiting GPS clocks are actually negligible, a naive calculation appears to show that such effects are significant, depending on whether the SV clock is between the

Parametric seeding of a microresonator optical frequency comb

July 16, 2013
Author(s)
Scott B. Papp, Pascal P. Del'Haye, Scott A. Diddams
We have investigated parametric seeding of a microresonator frequency comb (microcomb) by way of a pump laser with two intensity modulation sidebands. We show that the pump-sideband spacing is precisely replicated throughout the microcomb's optical

Mode reconstruction of a light field by multi-photon statistics

July 15, 2013
Author(s)
Elizabeth A. Goldschmidt, Fabrizio Piacentini, I. Ruo Berchera, Sergey V. Polyakov, Silke Peters, Stefan Kuck, Giorgio Brida, Ivo P. Degiovanni, Alan L. Migdall, Marco Genovese
Knowing the underlying number and structure of occupied modes of a light field plays a crucial role in minimizing loss and decoherence of quantum information. Typically, full characterization of the mode structure involves a series of several separate

Superposition, Entanglement, and Raising Schroedinger's Cat

July 12, 2013
Author(s)
David J. Wineland
This is a written version of the lecture I presented in connection with the Nobel Prize ceremonies in December 2012. The paper briefly summarizes experiments on quantum state manipulaiton and measurement in the context of trapped atomic ions. The focus of

Atomic data for beam-stimulated plasma spectroscopy in fusion plasmas

July 11, 2013
Author(s)
O. Marchuk, Yuri Ralchenko, David R. Schultz, W. Biel, T. Schlummer, TEXTOR Team
Injection of high energy atoms into a confined plasma volume is an established diagnostic technique in fusion research. This method strongly depends on the quality of atomic data for charge exchange spectroscopy (CXRS), motional Stark effect (MSE) and beam

Atomic Data for Iron-group Elements of Astrophysical Interest

July 11, 2013
Author(s)
Gillian Nave, Craig J. Sansonetti, J C. Pickering, Matthew Ruffoni, Anne P. Thorne, Florence Liggins
The joint project between NIST and Imperial College London to measure spectra of singly-ionized iron-group elements using Fourier transform and high-resolution grating spectroscopy is described.

Mechanical Control of a Microrod-Resonator Optical Frequency Comb

July 8, 2013
Author(s)
Scott B. Papp, Pascal P. Del'Haye, Scott A. Diddams
Robust control and stabilization of optical frequency combs enables an extraordinary range of scientific and technological applications, including frequency metrology at extreme levels of precision, novel spectroscopy of quantum gases and of molecules from

Demonstration of a dressed-state phase gate for trapped ions

June 28, 2013
Author(s)
Ting Rei Tan, John P. Gaebler, Ryan S. Bowler, Yiheng Lin, John D. Jost, Dietrich G. Leibfried, David J. Wineland
We demonstrate a trapped ion entangling gate scheme proposed by Bermudez et~al [Phys. Rev. A 85, 040302 (2012)]. Simultaneous excitation of a strong carrier and a single sideband transition enables deterministic creation of entangled states. The method

Comparison and Analysis of Collisional-Radiative Models at the NLTE-7 Workshop

June 25, 2013
Author(s)
Yuri Ralchenko, H.-K. Chung, S Hansen, C. Bowen, C. J. Fontes
We present the main results of the 7th Non-Local Thermodynamic Equilibrium Code Comparison Workshop held in December 2011 in Vienna, Austria. More than twenty researchers from nine countries, who actively work on development of collisional-radiative codes

Laser-Machined Ultra-High-Q Microrod Resonators for Nonlinear Optics

June 7, 2013
Author(s)
Pascal P. Del'Haye, Scott B. Papp, Scott A. Diddams
Optical whispering-gallery microresonators are useful tools in microphotonics, and non-linear optics at very low threshold powers. Here, we present details about the fabrication of ultra-high-Q whispering-gallery-mode (WGM) resonators made by CO2-laser
Was this page helpful?