Now showing items 1-20 of 421

    • Postselection-free energy-time entanglement 

      Strekalov, D. V.; Pittman, T.B.; Sergienko, A. V.; Shih, Y. H.; Kwiat, P. G. (American Physical Society (APS), 1996-07-01)
      We report a two-photon interference experiment that realizes a postselection-free test of Bell's inequality based on energy-time entanglement. In contrast with all previous experiments of this type, the employed entangled ...
    • Can Two-Photon Interference be Considered the Interference of Two Photons? 

      Pittman, T. B.; Strekalov, D. V.; Migdall, A.; Rubin, M. H.; Sergienko, A. V.; Shih, Y. H. (American Physical Society (APS), 1996-09-02)
      We report on a “postponed compensation” experiment in which the observed two-photon entangled state interference cannot be pictured in terms of the overlap of the two individual photon wave packets of a parametric ...
    • Electron-positron jets associated with the quasar 3C279 

      Wardle, J.F.C.; Homan, D.C.; Ojha, R.; Roberts, D.H. (Brandeis University, 1998)
      A long outstanding problem in extragalactic astrophysics is the composition of the relativistic jets of plasma streaming from the nuclei of quasars and active galaxies - whether it is predominantly a "normal" (electron-proton) ...
    • Multi-Photon Entanglement and Quantum Teleportation 

      Shih, Yanhua (U. S. Army Research Office, 1999-07-31)
      The project "Multi-Photon Entanglement and Quantum Teleportation" concerns a series of experimental and theoretical investigations on multi-photon entangled states and the applications, for example, quantum teleportation. ...
    • The Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) 

      Stark, Antony A.; Bally, John; Balm, Simon P.; Bania, T. M.; Bolatto, Alberto D.; Chamberlin, Richard A.; Engargiola, Gregory; Huang, Maohai; Ingalls, James G.; Jacobs, Karl; Jackson, James M.; Kooi, Jacob W.; Lane, Adair P.; Lo, K.-Y.; Marks, Rodney D.; Martin, Christopher L.; Mumma, Dennis; Ojha, Roopesh; Schieder, Rudolf; Staguhn, Johannes; Stutzki, Juergen; Walker, Christopher K.; Wilson, Robert W.; Wright, Gregory A.; Zhang, Xiaolei; Zimmermann, Peter; Zimmermann, Ruediger (IOP, 2000-12-15)
      AST/RO, a 1.7 m diameter telescope for astronomy and aeronomy studies at wavelengths between 200 and 2000 microns, was installed at the South Pole during the 1994-1995 Austral summer. The telescope operates continuously ...
    • AST/RO Observations of Atomic Carbon near the Galactic Center 

      Ojha, Roopesh; Stark, Antony A.; Hsieh, Henry H.; Lane, Adair P.; Chamberlin, Richard A.; Bania, Thomas M.; Bolatto, Alberto D.; Jackson, James M.; Wright, Gregory A. (IOP, 2001-02-10)
      We present a coarsely sampled map of the region |l| ≤ 2°, |b| ≤ 0°1 in the 492 GHz (³P₁ → ³P₀) fine-structure transition of neutral carbon, observed with the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO). ...
    • Parsec-Scale Blazar Monitoring: Proper Motions 

      Homan, Daniel C.; Ojha, Roopesh; Wardle, John F. C.; Roberts, David H.; Aller, Margo F.; Aller, Hugh D.; Philip A. Hughes (IOP, 2001-03-10)
      We present proper motions obtained from a dual-frequency, six-epoch, VLBA polarization experiment monitoring a sample of 12 blazars. The observations were made at 15 and 22 GHz at bimonthly intervals over 1996. A total of ...
    • Probabilistic quantum logic operations using polarizing beam splitters 

      Pittman, T. B.; Jacobs, B. C.; Franson, J. D. (American Physical Society (APS), 2001-11-16)
      It has previously been shown that probabilistic quantum logic operations may be performed using linear optical elements, additional photons (ancilla), and post-selection based on the output of single-photon detectors. Here ...
    • Parsec-Scale Blazar Monitoring: Flux and Polarization Variability 

      Homan, Daniel C.; Ojha, Roopesh; Wardle, John F. C.; Roberts, David H.; Aller, Margo F.; Aller, Hugh D.; Hughes, Philip A. (IOP, 2002-03-20)
      We present analysis of the flux density and polarization variability of parsec-scale radio jets from a dual-frequency, six-epoch, VLBA polarization experiment monitoring 12 blazars. The observations were made at 15 and 22 ...
    • Demonstration of Nondeterministic Quantum Logic Operations Using Linear Optical Elements 

      Pittman, T. P.; Jacobs, B. C.; Franson, J.D. (American Physical Society (APS), 2002-06-06)
      Knill, Laflamme, and Milburn [Nature (London) 409, 46 (2001)] recently showed that nondeterministic quantum logic operations could be performed using linear optical elements, additional photons (ancilla), and postselection ...
    • 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 ...
    • Single photons on pseudodemand from stored parametric down-conversion 

      Pittman, T.B.; Jacobs, B. C.; Franson, J.D. (American Physical Society (APS), 2002-10-10)
      We describe the results of a parametric down-conversion experiment in which the detection of one photon of a pair causes the other photon to be switched into a storage loop. The stored photon can then be switched out of ...
    • Demonstration of feed-forward control for linear optics quantum computation 

      Pittman, T.B.; Jacobs, B. C.; Franson, J.D. (American Physical Society (APS), 2002-11-14)
      One of the main requirements in linear optics quantum computing is the ability to perform single-qubit operations that are controlled by classical information fed forward from the output of single-photon detectors. These ...
    • Cyclical quantum memory for photonic qubits 

      Pittman, T.B.; Franson, J.D. (American Physical Society (APS), 2002-12-05)
      We have performed a proof-of-principle experiment in which qubits encoded in the polarization states of single photons from a parametric down-conversion source were coherently stored and read out from a quantum memory ...
    • Predictive Mining of Time Series Data in Astronomy 

      Perlman, Eric; Java, Akshay (2003-01-01)
      We discuss the development of a Java toolbox for astronomical time series data. Rather than using methods conventional in astronomy (e.g., power spectrum and cross-correlation analysis) we employ rule discovery techniques ...
    • Violation of Bell’s Inequality with Photons from Independent Sources 

      Pittman, T.B.; Franson, J.D. (American Physical Society (APS), 2003-06-19)
      We report a violation of Bell’s inequality using one photon from a parametric down-conversion source and a second photon from an attenuated laser beam. The two photons were entangled at a beam splitter using the postselection ...
    • Experimental controlled-NOT logic gate for single photons in the coincidence basis 

      Pittman, T. P.; Fitch, M. J.; Jacobs, B. C.; Franson, J. D. (American Physical Society (APS), 2003-09-26)
      We report a proof-of-principle demonstration of a probabilistic controlled-NOT gate for single photons. Single-photon control and target qubits were mixed with a single ancilla photon in a device constructed using only ...
    • Photon-number resolution using time-multiplexed single-photon detectors 

      Fitch, M. J.; Jacobs, B. C.; Pittman, T.B.; Franson, J.D. (American Physical Society (APS), 2003-10-10)
      Photon-number-resolving detectors are needed for a variety of applications including linear-optics quantum computing. Here we describe the use of time-multiplexing techniques that allow ordinary single-photon detectors, ...
    • Accurate Astrometry of 22 Southern Hemisphere Radio Sources 

      Fey, Alan L.; Ojha, Roopesh; Jauncey, David L.; Johnston, Kenneth J.; Reynolds, John E.; Lovell, James E. J.; Tzioumis, Anastasios K.; Quick, Jonathan F. H.; Nicolson, George D.; Ellingsen, Simon P.; McCulloch, Peter M.; Koyama, Yasuhiro (IOP, 2003-12-03)
      Milliarcsecond-accurate radio positions for 22 southern hemisphere extragalactic sources are reported. These positions are derived from Mark III very long baseline interferometry observations made between 2003 February and ...
    • The Impact of Interstellar Scintillation on Astrometric VLBI 

      Jauncey, David; Lovell, James; Ojha, Roopesh; Fey, Alan L.; Koyama, Yasuhiro; Bignall, Hayley E.; Kedziora-Chudczer, Lucyna; Macquart, Jean-Pierre; Rickett, Barney J.; Titov, Oleg; Tzioumis, Anastasios K. (2004)
      We review the evidence demonstrating the interstellar scintillation (ISS) is the principal mechanism responsible for the intra-day variability (IDV) seen at cm wavelengths in many compact, flat-spectrum extra-galactic radio ...