Now showing items 295-314 of 841

    • A Hard X-ray Survey of Radio-Selected Blazars 

      Langejahn, Marcus; Kadler, Matthias; Wilms, Jorn; Bock, M.; Baumgartner, W.H.; Gehrels, N.; Markwardt, C.B.; Tueller, J.
      The MOJAVE program has been monitoring a statistically complete sample of 135 radio-loud active galactic nuclei (AGN) of the northern hemisphere using the Very Long Baseline Array (VLBA). This sample, dominated by low-peaked ...
    • Heralded two-photon entanglement from probabilistic quantum logic operations on multiple parametric down-conversion sources 

      Pittman, T.B.; Donegan, M. M.; Fitch, M. J.; Jacobs, B. C.; Franson, J.D.; Kok, P.; Lee, Hwang; Dowling, J. P. (IEEE, 2018-10-29)
      An ideal controlled-NOT gate followed by projective measurements can be used to identify specific Bell states of its two input qubits. When the input qubits are each members of independent Bell states, these projective ...
    • Heralding single photons from pulsed parametric down-conversion 

      Pittman, T.B.; Jacobs, B. C.; Franson, J.D. (Elsevier, 2004-11-23)
      We describe an experiment in which photon pairs from a pulsed parametric down-conversion source were coupled into single-mode fibers. Detecting one of the photons heralded the presence of the other photon in its fiber with ...
    • HESS and Fermi-LAT discovery of γ-rays from the blazar 1ES 1312−423 

      Ojha, R.; Perkins, J. S. (Oxford University Press, 2013-08-01)
      A deep observation campaign carried out by the High Energy Stereoscopic System (HESS) on Centaurus A enabled the discovery of γ-rays from the blazar 1ES 1312−423, 2° away from the radio galaxy. With a differential flux at ...
    • High resolution rapid response observations of compact radio sources with the Ceduna Hobart Interferometer (CHI) 

      Blanchard, J. M.; Lovell, J. E. J.; Ojha, R.; Kadler, M.; Dickey, J. M.; Edwards, P. G. (EDP sciences, 2012-02-17)
      Context. Frequent, simultaneous observations across the electromagnetic spectrum are essential to the study of a range of astrophysical phenomena including active galactic nuclei. A key tool of such studies is the ability ...
    • High upward fluxes of formic acid from a boreal forest canopy 

      Schobesberger, Siegfried; Lopez‐Hilfiker, Felipe D.; Taipale, Ditte; Millet, Dylan B.; D'Ambro, Emma L.; Rantala, Pekka; Mammarella, Ivan; Zhou, Putian; Wolfe, Glenn M.; Lee, Ben H.; Boy, Michael; Thornton, Joel A. (AGU Pubication, 2016-08-26)
      Eddy covariance fluxes of formic acid, HCOOH, were measured over a boreal forest canopy in spring/summer 2014. The HCOOH fluxes were bidirectional but mostly upward during daytime, in contrast to studies elsewhere that ...
    • High-Fidelity Quantum Logic Operations and Entangled Ancilla States 

      Franson, J.D.; Donegan, M. M.; Fitch, M. J.; Jacobs, B. C.; Pittman, T. B. (OSA Publishing, 2003-06)
      We describe a high-fidelity approach to linear optics quantum computing in which the quantum logic operations always produce an output. A method for generating the required entangled states is also described.
    • High-Fidelity Quantum Logic Operations Using Linear Optical Elements 

      Franson, J.D.; Donegan, M. M.; Fitch, M.J.; Jacobs, B. C.; Pittman, T.B. (American Physical Society (APS), 2002-09-04)
      Knill, Laflamme, and Milburn [Nature (London) 409, 46 (2001)] have shown that quantum logic operations can be performed using linear optical elements and additional ancilla photons. Their approach is probabilistic in the ...
    • High-Resolution Grating Spectroscopy of GRB 020405 with the Chandra Low Energy Transmission Grating Spectrometer 

      Mirabal, N.; Paerels, F.; Halpern, J. P. (IOP, 2002-12-16)
      We present high-resolution X-ray spectroscopy of GRB 020405 obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra X-Ray Observatory starting 1.68 days after the burst. The spectrum ...
    • High-resolution observations of 6.7-GHz methanol masers with the Long Baseline Array 

      Dodson, R.; Ojha, R.; Ellingsen, S. P. (Oxford University Press, 2004-07-01)
      We have used the Australian Long Baseline Array (LBA) to produce milliarcsecond images of five sites of methanol (CH3OH) maser emission at 6.7 GHz. These are all sites that have linear morphologies at arcsecond resolutions, ...
    • High-Resolution Observations of Centaurus A 

      Muller, Cornelia; Blanchard, J.; Bock, M.; Carpenter, B.; Dutka, M.; Furst, F.; Grafe, C.; Großberger, C.; Kadler, M.; Krauß, F.; Markowitz, A.; Ojha, R.; Perucho, M.; Pottschmidt, K.; Ros, E.; Rothschild, R.; Schulz, R.; Trustedt, J.; Wilms, J.; the TANAMI Collaboration (European Space Agency, 2011)
      The closest active galaxy Centaurus A is regularly observed at milliarcsecond resolution within the framework of the Southern Hemisphere AGN monitoring program TANAMI. Additional multiwavelength observations up to gamma-ray ...
    • Highest gamma-ray flux level detected from very high redshift blazar B3 1343+451 

      Ojha, Roopesh; Dutka, Michael; Torresi, Eleonora (The Astronomer's Telegram, 2011-12-01)
    • High‐accuracy zenith delay prediction at optical wavelengths 

      Mendes, V. B.; Pavlis, E. C. (AGU Pubication, 2004-07-16)
      A major limitation in accuracy in modern satellite laser ranging is the modeling of atmospheric refraction. Recent improvements in this area include the development of mapping functions to project the atmospheric delay ...
    • Holevo's bound from a general quantum fluctuation theorem 

      Kafri, Dvir; Deffner, Sebastian (American Physical Society (APS), 2012-10-22)
      We give a derivation of Holevo's bound using an important result from nonequilibrium statistical physics, the fluctuation theorem. To do so we develop a general formalism of quantum fluctuation theorems for two-time ...
    • Holey Fiber Microcavities 

      Hendrickson, S. M.; Pittman, T.B.; Franson, J.D. (OSA Publishing, 2008)
      Microcavities have been formed by placing mirrors on the ends of a short section of holey fiber. The resonant behavior of these devices was analyzed and their suitability for use in nonlinear optics experiments at single-photon ...
    • Hot-Carrier Relaxation in CdSe/CdS Core/Shell Nanoplatelets 

      Pelton, Matthew; Wang, Yana; Fedin, Igor; Talapin, Dmitri V.; O’Leary, Stephen K. (ACS Publications, 2019-12-11)
      We present time-resolved photoluminescence (PL) spectroscopy of a series of colloidal CdSe/CdS core/shell nanoplatelets with different core and shell thicknesses. Exciton numbers are determined from the integrated PL ...
    • AN HST PROPER-MOTION STUDY OF THE LARGE-SCALE JET OF 3C273 

      Meyer, Eileen T.; Sparks, William B.; Georganopoulos, Markos; Anderson, Jay; Marel, Roeland van der; Biretta, John; Sohn, Sangmo Tony; Chiaberge, Marco; Perlman, Eric; Norman, Colin (IOP, 2016-02-18)
      The radio galaxy 3C 273 hosts one of the nearest and best-studied powerful quasar jets. Having been imaged repeatedly by the Hubble Space Telescope (HST) over the past twenty years, it was chosen for an HST program to ...
    • Hubble Space Telescope Observations of [O III] Emission in Nearby QSO2s: Physical Properties of the Ionised Outflows 

      Falcao, Anna Trindade; Kraemer, S. B.; Fischer, T. C.; Crenshaw, D. M.; Revalski, M.; Schmitt, H. R.; Vestergaard, M.; Elvis, M.; Gaskell, C. M.; Hamann, F.; Ho, L. C.; Hutchings, J.; Mushotzky, R.; Netzer, H.; Storchi-Bergmann, T.; Turner, T.J.; Ward, M.J.
      We use Hubble Space Telescope (HST)/ Space Telescope Imaging Spectrograph (STIS) long-slit G430M and G750M spectra to analyse the extended [O~III] 5007A emission in a sample of twelve nearby (z < 0.12) luminous (L_bol > ...
    • HUNTING FOR TREASURES AMONG THE FERMI UNASSOCIATED SOURCES: A MULTIWAVELENGTH APPROACH 

      Acero, F.; Donato, D.; Ojha, R.; Stevens, J.; Edwards, P. G.; Ferrara, E.; J. Blanchard, J.; Lovell, J. E. J.; Thompson, D. J. (IOP, 2013-12-20)
      The Fermi Gamma-Ray Space Telescope has been detecting a wealth of sources where the multiwavelength counterpart is either inconclusive or missing altogether. We present a combination of factors that can be used to identify ...
    • Hybrid approach for optical quantum computing 

      Franson, J.D.; Jacobs, B. C.; Pittman, T.B. (OSA Publishing, 2004)
      We describe a hybrid approach to quantum computing in which linear optical elements are used to perform the logic operations while relatively small nonlinear effects are used to avoid the need for ancilla photons.