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Search Publications by: Dietrich Leibfried (Fed)

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Displaying 201 - 225 of 261

Enhanced Quantum State Detection Efficiency Through Quantum Information Processing

January 1, 2005
Author(s)
T Schaetz, Murray D. Barrett, Dietrich G. Leibfried, Joseph W. Britton, J Chiaverini, Wayne M. Itano, John D. Jost, E Knill, Christopher Langer, David J. Wineland
We investigate theoretically and experimentally how quantum state-detection efficiency is improved by the use of quantum information processing (QIP). Experimentally, we encode the state of one 9Be ion qubit with one additional ancilla qubit. By measuring

Realization of quantum error correction

December 2, 2004
Author(s)
J Chiaverini, Dietrich G. Leibfried, Tobias Schaetz, Murray D. Barrett, Brad R. Blakestad, Joseph W. Britton, Wayne M. Itano, John D. Jost, Emanuel H. Knill, C. Langer, R Ozeri, David J. Wineland
Scalable quantum computation and communication require error control to protect quantum information against unavoidable noise. Quantum error correction protects quantum information stored in two-level quantum systems (qubits) by rectifying errors with

Quantum information processing with trapped ions

July 25, 2004
Author(s)
Murray D. Barrett, Tobias Schaetz, J Chiaverini, Dietrich Leibfried, Joseph W. Britton, Wayne M. Itano, John D. Jost, Emanuel Knill, C. Langer, R Ozeri, David J. Wineland
We report experiments on the creation and manipulation ofmulti-particle entangled states of trapped atomic ions. The experiments reported here, quantum dense coding and quantum teleportation, constitute a significant step toward performing large-scale

Quantum Dense Coding with Atomic Qubits

January 1, 2004
Author(s)
T Schaetz, Murray D. Barrett, Dietrich G. Leibfried, J Chiaverini, Joseph W. Britton, Wayne M. Itano, John D. Jost, Christopher Langer, David J. Wineland
We report the implementation of quantum dense coding on individual atomic qubits with the use of two trapped 9Be+ ions. The protocol is implemented with a complete Bell measurement that distinguishes the four operations used to encode two bits of classical

Toward Heisenberg-Limited Spectroscopy with Multiparticle Entangled States

January 1, 2004
Author(s)
Dietrich G. Leibfried, Murray D. Barrett, T Schaetz, Joseph W. Britton, J Chiaverini, Wayne M. Itano, John D. Jost, Christopher Langer, David J. Wineland
The precision in spectroscopy of any quantum system is fundamentally limited by the Heisenberg uncertainty relation for energy and time. For N systems, this limit requires that they be in a quantum-mechanically entangled state. We describe a scalable

Ion Optical Clocks and Quantum Information Processing

May 1, 2003
Author(s)
David J. Wineland, James C. Bergquist, Till P. Rosenband, Piet Schmidt, Wayne M. Itano, John J. Bollinger, Dietrich G. Leibfried, W Oskay
We summarize experiments at NIST that (1) use guantum gates to entabgle ions and thereby improve the measurement signal-to-noise ratio in spectroscopy and (2) implement sympathetic cooling and quantum state transfer techniques, which might be used to

Experimental Demonstration of a Technique to Generate Arbitrary Quantum Superposition States of a Harmonically Bound Spin-1/2 Particle

January 24, 2003
Author(s)
A Ben-kish, B M. Demarco, V Meyer, Mary A. Rowe, Joseph W. Britton, Wayne M. Itano, Branislav M. Jelenkovic, Christopher Langer, Dietrich Leibfried, Till P. Rosenband, David J. Wineland
Using a single, harmonically trapped 9Be+ ion, we experimentally demonstrate a technique for generation of arbitrary states of a two-level particle confined by a harmonic potential. Rather than engineering a single Hamiltonian that evolves the system to a

Building Blocks for a Scalable Quantum Information Processor Based On Trapped Ions

January 1, 2003
Author(s)
Dietrich G. Leibfried, Murray D. Barrett, A Ben-kish, Joseph W. Britton, J Chiaverini, B. L. DeMarco, Wayne M. Itano, Branislav M. Jelenkovic, John D. Jost, Christopher Langer, D Lucas, V Meyer, Till P. Rosenband, M A. Rowe, T Schaetz, David J. Wineland
We describe the underlying concept and experimental demonstration of the basic building blocks of a scalable quantum information processor architecture using trapped ion-qubits. The trap structure is divided into many subregions. In each several ion-qubits

Experimental demonstration of robust, high-fidelity geometric two ion-qubit phase gate

January 1, 2003
Author(s)
Dietrich G. Leibfried, B. L. DeMarco, V Meyer, D Lucas, Murray D. Barrett, Joseph W. Britton, Wayne M. Itano, Branislav M. Jelenkovic, Christopher Langer, Till P. Rosenband, David J. Wineland
Universal logic gates for two quantum bits (qubits) form an essential ingredient of quantum computation. Dynamical gates have been proposed in the context of trapped ions; however, geometric phase gates (which change only the phase of the physical qubits)

Quantum information processing and multiplexing with trapped ions

January 1, 2003
Author(s)
David J. Wineland, Dietrich G. Leibfried, B. L. DeMarco, V Meyer, M A. Rowe, A Ben kish, Murray D. Barrett, Joseph W. Britton, J Hughes, Wayne M. Itano, Branislav M. Jelenkovic, Christopher Langer, D Lucas, Till P. Rosenband
We report experiments on coherent quantum-state synthesis and control of trapped atomic ions. This work has the overall goal of performing large-scale quantum information processing; however, such techniques can also be applied to fundamental tests and