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  • 1
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    Diamagnetic correction to the ^{9}Be^{+} ground-state hyperfine constant (2011)
    American Physical Society (APS)
    Details
    Publication Date: 2011-07-23
    Description: Author(s): N. Shiga, W. M. Itano, and J. J. Bollinger We report an experimental determination of the diamagnetic correction to the 9 Be + ground state hyperfine constant A . We measured A = −625 008 837.371(11) Hz at a magnetic field B of 4.4609 T. Comparison with previous results, obtained at lower values of B (0.68 T and 0.82 T), yields the diamagnetic ... [Phys. Rev. A 84, 012510] Published Fri Jul 22, 2011
    Keywords: Atomic and molecular structure and dynamics
    Print ISSN: 1050-2947
    Electronic ISSN: 1094-1622
    Topics: Physics
    Published by American Physical Society (APS)
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  • 2
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    An optical clock based on a single trapped 199Hg+ ion (2001)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 2001-07-14
    Description: Microwave atomic clocks have been the de facto standards for precision time and frequency metrology over the past 50 years, finding widespread use in basic scientific studies, communications, and navigation. However, with its higher operating frequency, an atomic clock based on an optical transition can be much more stable. We demonstrate an all-optical atomic clock referenced to the 1.064-petahertz transition of a single trapped 199Hg+ ion. A clockwork based on a mode-locked femtosecond laser provides output pulses at a 1-gigahertz rate that are phase-coherently locked to the optical frequency. By comparison to a laser-cooled calcium optical standard, an upper limit for the fractional frequency instability of 7 x 10(-15) is measured in 1 second of averaging-a value substantially better than that of the world's best microwave atomic clocks.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Diddams, S A -- Udem, T -- Bergquist, J C -- Curtis, E A -- Drullinger, R E -- Hollberg, L -- Itano, W M -- Lee, W D -- Oates, C W -- Vogel, K R -- Wineland, D J -- New York, N.Y. -- Science. 2001 Aug 3;293(5531):825-8. Epub 2001 Jul 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. sdiddams@boulder.nist.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11452082" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
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    A decoherence-free quantum memory using trapped ions (2001)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 2001-03-10
    Description: We demonstrate a decoherence-free quantum memory of one qubit. By encoding the qubit into the decoherence-free subspace (DFS) of a pair of trapped 9Be+ ions, we protect the qubit from environment-induced dephasing that limits the storage time of a qubit composed of a single ion. We measured the storage time under ambient conditions and under interaction with an engineered noisy environment and observed that encoding into the DFS increases the storage time by up to an order of magnitude. The encoding reversibly transfers an arbitrary qubit stored in a single ion to the DFS of two ions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kielpinski, D -- Meyer, V -- Rowe, M A -- Sackett, C A -- Itano, W M -- Monroe, C -- Wineland, D J -- New York, N.Y. -- Science. 2001 Feb 9;291(5506):1013-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, USA. davidk@boulder.nist.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11232562" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
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    Bragg diffraction from crystallized ion plasmas (1998)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 1998-02-10
    Description: Single crystals of a one-component plasma were observed by optical Bragg diffraction. The plasmas contained 10(5) to 10(6) single-positive beryllium-9 ions (9Be+) at particle densities of 10(8) to 10(9) per cubic centimeter. In approximately spherical plasmas, single body-centered cubic (bcc) crystals or, in some cases, two or more bcc crystals having fixed orientations with respect to each other were observed. In some oblate plasmas, a mixture of bcc and face-centered cubic ordering was seen. Knowledge of the properties of one-component plasma crystals is required for models of white dwarfs and neutron stars, which are believed to contain matter in that form.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Itano -- Bollinger -- Tan -- Jelenkovic -- Huang -- Wineland -- New York, N.Y. -- Science. 1998 Jan 30;279(5351):686-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80303, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9445470" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
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    Direct observations of structural phase transitions in planar crystallized ion plasmas (1998)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1998-11-13
    Description: Laser-cooled 9Be+ ions confined in two-dimensionally extended lattice planes were directly observed, and the images were used to characterize the structural phases of the ions. Five different stable crystalline phases were observed, and the energetically favored structure could be sensitively tuned by changing the areal density of the confined ions. The experimental results are in good agreement with theoretical predictions for the planar (infinite in two dimensions) one-component plasma. Qualitatively similar structural phase transitions occur, or are predicted to occur, in other experimentally realizable planar systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Mitchell -- Bollinger -- Dubin -- Huang -- Itano -- Baughman -- New York, N.Y. -- Science. 1998 Nov 13;282(5392):1290-3.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉T. B. Mitchell, J. J. Bollinger, X.-P. Huang, W. M. Itano, Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80303, USA. D. H. E. Dubin, Department of Physics, University of California at San Diego, La Joll.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9812887" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
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    Optimized dynamical decoupling in a model quantum memory (2009)
    Nature Publishing Group (NPG)
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    Publication Date: 2009-04-28
    Description: Any quantum system, such as those used in quantum information or magnetic resonance, is subject to random phase errors that can dramatically affect the fidelity of a desired quantum operation or measurement. In the context of quantum information, quantum error correction techniques have been developed to correct these errors, but resource requirements are extraordinary. The realization of a physically tractable quantum information system will therefore be facilitated if qubit (quantum bit) error rates are far below the so-called fault-tolerance error threshold, predicted to be of the order of 10(-3)-10(-6). The need to realize such low error rates motivates a search for alternative strategies to suppress dephasing in quantum systems. Here we experimentally demonstrate massive suppression of qubit error rates by the application of optimized dynamical decoupling pulse sequences, using a model quantum system capable of simulating a variety of qubit technologies. We demonstrate an analytically derived pulse sequence, UDD, and find novel sequences through active, real-time experimental feedback. The latter sequences are tailored to maximize error suppression without the need for a priori knowledge of the ambient noise environment, and are capable of suppressing errors by orders of magnitude compared to other existing sequences (including the benchmark multi-pulse spin echo). Our work includes the extension of a treatment to predict qubit decoherence under realistic conditions, yielding strong agreement between experimental data and theory for arbitrary pulse sequences incorporating nonidealized control pulses. These results demonstrate the robustness of qubit memory error suppression through dynamical decoupling techniques across a variety of qubit technologies.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Biercuk, Michael J -- Uys, Hermann -- VanDevender, Aaron P -- Shiga, Nobuyasu -- Itano, Wayne M -- Bollinger, John J -- England -- Nature. 2009 Apr 23;458(7241):996-1000. doi: 10.1038/nature07951.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉NIST Time and Frequency Division, Boulder, Colorado 80305, USA. biercuk@boulder.nist.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19396139" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 7
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    Implementation of the semiclassical quantum Fourier transform in a scalable system (2005)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 2005-05-14
    Description: We report the implementation of the semiclassical quantum Fourier transform in a system of three beryllium ion qubits (two-level quantum systems) confined in a segmented multizone trap. The quantum Fourier transform is the crucial final step in Shor's algorithm, and it acts on a register of qubits to determine the periodicity of the quantum state's amplitudes. Because only probability amplitudes are required for this task, a more efficient semiclassical version can be used, for which only single-qubit operations conditioned on measurement outcomes are required. We apply the transform to several input states of different periodicities; the results enable the location of peaks corresponding to the original periods. This demonstration incorporates the key elements of a scalable ion-trap architecture, suggesting the future capability of applying the quantum Fourier transform to a large number of qubits as required for a useful quantum factoring algorithm.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chiaverini, J -- Britton, J -- Leibfried, D -- Knill, E -- Barrett, M D -- Blakestad, R B -- Itano, W M -- Jost, J D -- Langer, C -- Ozeri, R -- Schaetz, T -- Wineland, D J -- New York, N.Y. -- Science. 2005 May 13;308(5724):997-1000.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Institute of Standards and Technology, Boulder, CO 80305, USA. john.chiaverini@boulder.nist.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15890877" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
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    Toward Heisenberg-limited spectroscopy with multiparticle entangled states (2004)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 2004-06-05
    Description: 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 method of spectroscopy that can potentially take full advantage of entanglement to reach the Heisenberg limit and has the practical advantage that the spectroscopic information is transferred to states with optimal protection against readout noise. We demonstrate our method experimentally with three beryllium ions. The spectroscopic sensitivity attained is 1.45(2) times as high as that of a perfect experiment with three non-entangled particles.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Leibfried, D -- Barrett, M D -- Schaetz, T -- Britton, J -- Chiaverini, J -- Itano, W M -- Jost, J D -- Langer, C -- Wineland, D J -- New York, N.Y. -- Science. 2004 Jun 4;304(5676):1476-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. dil@boulder.nist.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15178794" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
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  • 9
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    Spectroscopy using quantum logic (2005)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 2005-07-30
    Description: We present a general technique for precision spectroscopy of atoms that lack suitable transitions for efficient laser cooling, internal state preparation, and detection. In our implementation with trapped atomic ions, an auxiliary "logic" ion provides sympathetic laser cooling, state initialization, and detection for a simultaneously trapped "spectroscopy" ion. Detection is achieved by applying a mapping operation to each ion, which results in a coherent transfer of the spectroscopy ion's internal state onto the logic ion, where it is then measured with high efficiency. Experimental realization, by using 9Be+ as the logic ion and 27Al+ as the spectroscopy ion, indicates the feasibility of applying this technique to make accurate optical clocks based on single ions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schmidt, P O -- Rosenband, T -- Langer, C -- Itano, W M -- Bergquist, J C -- Wineland, D J -- New York, N.Y. -- Science. 2005 Jul 29;309(5735):749-52.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. piet.schmidt@uibk.ac.at〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16051790" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
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  • 10
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    Frequency ratio of Al+ and Hg+ single-ion optical clocks; metrology at the 17th decimal place (2008)
    American Association for the Advancement of Science (AAAS)
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    Publication Date: 2008-03-08
    Description: Time has always had a special status in physics because of its fundamental role in specifying the regularities of nature and because of the extraordinary precision with which it can be measured. This precision enables tests of fundamental physics and cosmology, as well as practical applications such as satellite navigation. Recently, a regime of operation for atomic clocks based on optical transitions has become possible, promising even higher performance. We report the frequency ratio of two optical atomic clocks with a fractional uncertainty of 5.2 x 10(-17). The ratio of aluminum and mercury single-ion optical clock frequencies nuAl+/nuHg+ is 1.052871833148990438(55), where the uncertainty comprises a statistical measurement uncertainty of 4.3 x 10(-17), and systematic uncertainties of 1.9 x 10(-17) and 2.3 x 10(-17) in the mercury and aluminum frequency standards, respectively. Repeated measurements during the past year yield a preliminary constraint on the temporal variation of the fine-structure constant alpha of alpha/alpha = (-1.6+/-2.3) x 10(-17)/year.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rosenband, T -- Hume, D B -- Schmidt, P O -- Chou, C W -- Brusch, A -- Lorini, L -- Oskay, W H -- Drullinger, R E -- Fortier, T M -- Stalnaker, J E -- Diddams, S A -- Swann, W C -- Newbury, N R -- Itano, W M -- Wineland, D J -- Bergquist, J C -- New York, N.Y. -- Science. 2008 Mar 28;319(5871):1808-12. doi: 10.1126/science.1154622. Epub 2008 Mar 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. trosen@boulder.nist.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18323415" target="_blank"〉PubMed〈/a〉
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