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Browsing by Author "Uys, H"

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  • Sastrawan, J; Jones, C; Akhalwaya, I; Uys, H; Biercuk, MJ (American Physical Society, 2016-08)
    We introduce concepts from optimal estimation to the stabilization of precision frequency standards limited by noisy local oscillators. We develop a theoretical framework casting various measures for frequency standard ...
  • Green, TJ; Sastrawan, J; Uys, H; Biercuk, MJ (Institute of Physics, 2013-09)
    We address the problem of deriving analytic expressions for calculating universal decoherence-induced errors in qubits undergoing arbitrary, unitary, time-dependent quantum control protocols. We show that the fidelity of ...
  • Uys, H; Akhalwaya, I; Botha, N; Burd, S; Hendriks, A; Madigoe, R; Ombinda, S; Smit, A; Kloppers, H; Steyn, J; Botha, L (2012-10)
    In this presentation the authors discuss the technological relevance of quantum mechanics, and describe how researchers use light to control the atomic and molecular world at its most fundamental level.
  • Burd, CC; Du Toit, PJW; Uys, H (Optical Society of America, 2014-10)
    We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for ...
  • Uys, H; Biercuk, MJ; VanDevender, AP; Ospelkaus, C; Meiser, D; Ozeri, R; Bollinger, JJ (American Physical Society, 2010-11)
    The authors present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. They demonstrate ...
  • Uys, H; Biercuk, M; Van Devender, AP; Ospelkaus, C; Meiser, D; Ozeri, R; Bollinger, JJ (SAIP 2010, 2010-09)
    This paper investigates the decoherence of superpositions of hyperfine states of 9Be+ ions due to spontaneous scattering of off-resonant light. It was found that, contrary to conventional wisdom, elastic Raleigh scattering ...
  • Uys, H; Biercuk, M; Britton, JW; Van Devender, AP; Bollinger, JJ (SAIP 2010, 2010-09)
    This article reports on a calibrated measurement of 174 Yoctonewton using a cloud of 60 9 Be+ ion confined in a Penning ion trap. These measurements suggest that ion traps may form the basis of a new class of ultrasensitive ...
  • Britton, JW; Sawyer, BC; Keith, AC; Wang, CCJ; Freericks, JK; Uys, H; Biercuk, MJ; Bollinge, JJ (Macmillan Publishers, 2012-04)
    The presence of long-range quantum spin correlations underlies a variety of physical phenomena in condensed-matter systems, potentially including high-temperature superconductivity. However, many properties of exotic, ...
  • Soare, A; Ball, H; Hayes, D; Zhen, X; Jarratt, MC; Sastrawan, J; Uys, H; Biercuk, MJ (American Physical Society, 2014-04)
    We develop and demonstrate a technique to engineer universal unitary baths in quantum systems. Using the correspondence between unitary decoherence due to ambient environmental noise and errors in a control system for ...
  • Du Plessis, A; Strydom, CA; Uys, H; Botha, L; Roberts, T; Dlamini, TH (CSIR, 2010-09)
    Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This ...
  • Du Plessis, A; Strydom, CA; Uys, H; Botha, L; Roberts, T; Dlamini, TH (CSIR, 2010-08-31)
    Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This ...
  • Du Plessis, A; Strydom, CA; Uys, H; Hendriks, A; Botha, GN; Botha, LR (2011-07)
    Results from experiments aimed at bimolecular chemical reaction control of CO and H2 at room temperature and pressure, without any catalyst, using shaped femtosecond laser pulses are presented. A stable reaction product ...
  • Green, T; Uys, H; Biercuk, MJ (American Physical Society, 2012-07)
    Treating the effects of a time-dependent classical dephasing environment during quantum logic operations poses a theoretical challenge, as the application of noncommuting control operations gives rise to both dephasing and ...
  • Choudhary, SK; Konrad, T; Uys, H (American Physical Society, 2013-01)
    Unsharp positive operator-valued measurements allow a variety of measurement applications which minimally disrupt the state of the quantum system. Experimental schemes are proposed for implementing unsharp measurements on ...
  • Botha, L; Du Plessis, A; Uys, H; de Clercq, L (CSIR, 2010-09-01)
    Coherent control of quantum dynamics in optical, molecular and biological systems is a rapidly advancing field with many possible applications. This field of study was originally motivated by the goal of steering photoreactions ...
  • Konrad, T; Uys, H (American Physical Society, 2012-01)
    Unsharp measurements allow the estimation and tracking of quantum wave functions in real time with minimal disruption of the dynamics. Here we demonstrate that high-fidelity state monitoring, and hence quantum control, is ...
  • Bassa, H; Goyal, SK; Choudhary, SK; Uys, H; Diósi, L; Konrad, T (American Physical Society, 2015-09)
    The authors utilize a discrete (sequential) measurement protocol to investigate quantum process tomography of a single two-level quantum system, with an unknown initial state, undergoing Rabi oscillations. The ignorance ...
  • Uys, H; Biercuk, M; Van Devender, AP; Bollinger, JJ (SAIP 2010, 2010-09)
    The authors study pulse sequences that dynamically decouple 9Be+ ions from their decohering environment. The noise environment the ions see is artificially synthesized to emulate a variety of physical systems. By incorporating ...
  • Botha, N; Botha, L; Du Plessis, A; Uys, H; Schoewer, H (2010-10)
    The design of the pulse shaping setup as well as factors taken into account in choosing a specific setup will be discussed. We investigate the generation of simple shaped pulses to test our pulse shaper setup. Difference ...
  • Uys, H; Amini, JM; Wesenberg, JH; Seidelin, S; Britton, J; Bollinger, JJ; Leibfried, D; Ospelkaus, C; Van Deventer, AP; Wineland, DJ (SAIP 2010, 2010-09)
    The design, fabrication and preliminary testing of a chipscale, multi-zone, surface electrode ion trap is reported. The modular design and fabrication techniques used are anticipated to advance scalability of ion trap ...