Browsing Journal Articles by Author "Uys, H"

Now showing items 1-11 of 11

Analytically exploiting noise correlations inside the feedback loop to improve locked-oscillator performance

Author: Sastrawan, J ; Jones, C ; Akhalwaya, I ; Uys, H ; Biercuk, MJ Date: Aug 2016 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 variance in terms of ... Read more
Arbitrary quantum control of qubits in the presence of universal noise

Author: Green, TJ ; Sastrawan, J ; Uys, H ; Biercuk, MJ Date: Sep 2013 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 a control operation ... Read more
Coupled optical resonance laser locking

Author: Burd, CC ; Du Toit, PJW ; Uys, H Date: Oct 2014 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 locking the different ... Read more
Decoherence due to elastic rayleigh scattering

Author: Uys, H ; Biercuk, MJ ; VanDevender, AP ; Ospelkaus, C ; Meiser, D ; Ozeri, R ; Bollinger, JJ Date: Nov 2010 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 that under ... Read more
Engineered two-dimensional Ising interactions in a trapped-ion quantum simulator with hundreds of spins

Author: Britton, JW ; Sawyer, BC ; Keith, AC ; Wang, CCJ ; Freericks, JK ; Uys, H ; Biercuk, MJ ; Bollinge, JJ Date: Apr 2012 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, strongly correlated spin ... Read more
Experimental bath engineering for quantitative studies of quantum control

Author: Soare, A ; Ball, H ; Hayes, D ; Zhen, X ; Jarratt, MC ; Sastrawan, J ; Uys, H ; Biercuk, MJ Date: Apr 2014 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 quantum bits, we show ... Read more
High-order noise filtering in nontrivial quantum logic gates

Author: Green, T ; Uys, H ; Biercuk, MJ Date: Jul 2012 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 depolarization ... Read more
Implementation schemes for unsharp measurements with trapped ions

Author: Choudhary, SK ; Konrad, T ; Uys, H Date: Jan 2013 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 the qubit levels of ... Read more
Maintaining quantum coherence in the presence of noise through state monitoring

Author: Konrad, T ; Uys, H Date: Jan 2012 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 possible, even in ... Read more
Process tomography via sequential measurements on a single quantum system

Author: Bassa, H ; Goyal, SK ; Choudhary, SK ; Uys, H ; Diósi, L ; Konrad, T Date: Sep 2015 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 of the dynamical ... Read more
Spectroscopy and thermometry of drumhead modes in a mesoscopic trapped-ion crystal using entanglement

Author: Sawyer, BC ; Britton, JW ; Keith, AC ; Joseph Wang, CCJ ; Freericks, JK ; Uys, H ; Biercuk, MJ ; Bollinger, JJ Date: May 2012 We demonstrate spectroscopy and thermometry of individual motional modes in a mesoscopic 2D ion array using entanglement-induced decoherence as a method of transduction. Our system is a 400 µm-diameter planar crystal of several hundred 9Be+ ... Read more

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Browsing Journal Articles by Author "Uys, H"

Browsing Journal Articles by Author "Uys, H"

Browse

All of ResearchSpace

This Collection

Quick Links

Legislation and compliance

General Enquiries

Social Connect