383 research outputs found

    Dissipation-assisted quantum gates with cold trapped ions

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    It is shown that a two-qubit phase gate and SWAP operation between ground states of cold trapped ions can be realised in one step by simultaneously applying two laser fields. Cooling during gate operations is possible without perturbing the computation and the scheme does not require a second ion species for sympathetic cooling. On the contrary, the cooling lasers even stabilise the desired time evolution of the system. This affords gate operation times of nearly the same order of magnitude as the inverse coupling constant of the ions to a common vibrational mode.Comment: 4 pages, 5 figures, substantially revised versio

    Entanglement between motional states of a single trapped ion and light

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    We propose a generation method of Bell-type states involving light and the vibrational motion of a single trapped ion. The trap itself is supposed to be placed inside a high-QQ cavity sustaining a single mode, quantized electromagnetic field. Entangled light-motional states may be readily generated if a conditional measurement of the ion's internal electronic state is made after an appropriate interaction time and a suitable preparation of the initial state. We show that all four Bell states may be generated using different motional sidebands (either blue or red), as well as adequate ionic relative phases.Comment: 4 pages, LaTe

    Sympathetic cooling of 9Be+^9Be^+ and 24Mg+^{24}Mg^+ for quantum logic

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    We demonstrate the cooling of a two species ion crystal consisting of one 9Be+^9Be^+ and one 24Mg+^{24}Mg^+ ion. Since the respective cooling transitions of these two species are separated by more than 30 nm, laser manipulation of one ion has negligible effect on the other even when the ions are not individually addressed. As such this is a useful system for re-initializing the motional state in an ion trap quantum computer without affecting the qubit information. Additionally, we have found that the mass difference between ions enables a novel method for detecting and subsequently eliminating the effects of radio frequency (RF) micro-motion.Comment: Submitted to PR

    Health beliefs, attitudes, and health-related quality of life in persons with fibromyalgia : mediating role of treatment adherence

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    Fibromyalgia is a chronic illness characterized by pain and fatigue. Persons with fibromyalgia experience increased the risk for poor mental and physical health-related quality of life, which may be dependent on multiple factors, including health beliefs, such as confidence in physicians and the health-care system, and health behaviors, such as treatment adherence. Respondents with fibromyalgia (n = 409) were recruited nationally, via support organizations, and completed self-report measures: Multidimensional Health Profile – Health Functioning Index (MHP-H), Short-Form-36 Health Survey (SF-36v2), and Medical Outcomes Study (MOS) Measure of Patient Adherence – General Adherence Items. In mediation models, belief in the healthcare system and health-care personnel, and health efficacy exerted an indirect effect through treatment adherence on mental and physical quality of life. Adaptive health beliefs and attitudes were related to greater treatment adherence and, in turn, to a better quality of life. Maladaptive health beliefs and mistrusting attitudes about physician-level and systemic-level healthcare provision are negatively related to both treatment adherence and consequent physical and mental health-related quality of life in persons with fibromyalgia. Future randomized controlled trials are needed to determine if therapeutic strategies to alter health values might improve adherence and self-rated health

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

    Economical and technological study of surface grinding versus face milling in hardened AISI D3 steel machining operations

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    [EN] This work deals with the technological and economic considerations required to select face milling vs. surface grinding operations in the manufacture of hardened steel flat surfaces for dies and moulds. In terms of technological considerations, factors such as component geometry, material and surface quality (dimensional tolerance and surface finish) are taken into account. The economic considerations include the cost of machine depreciation, labour and consumables (cutting tools in face milling vs. grinding wheels and dressing tool in surface grinding). A case study is presented based on the prismatic components in ceramic tile moulds and their associated manufacturing operations. Surface grinding and face milling experimentation was conducted on cold work steel AISI D3 (with hardness of 60 HRC) with aluminium oxide grinding wheels and coated tungsten carbide cutting tool, respectively. Technological attributes and economics of face milling are compared with surface grinding of this type of mould components. The main conclusion is that face milling with chamfered edge preparation in coated tungsten carbide tools is a competitive process, compared with surface grinding, in terms of product quality and economics.The research team would like to acknowledge the main support of the Caja Castello-Bancaixa Foundation and Universitat Jaume I, which support the project: "Integration of Planning, Execution and Control of High Speed Machining Operations in Collaborative Engineering Environments: Application in Moulds for Tile Industry", the ceramic tile mould company MACER S.L., and would like to extend their gratitude to Roberto Menendez, student of industrial engineering. Particular thanks go to the Programme Alssan: European Union Programme of High Level Scholarships for Latin America (scholarship no. E04D030982MX). Additional support was provided by Tecnologico de Monterrey through the research group in Mechatronics and Intelligent Machines (http://cidyt.mty.itesm/cimec).Vila Pastor, C.; Siller, H.; Rodríguez, C.; Bruscas Bellido, G.; Serrano, J. (2012). Economical and technological study of surface grinding versus face milling in hardened AISI D3 steel machining operations. International Journal of Production Economics. 138(2):273-283. doi:10.1016/j.ijpe.2012.03.028S273283138

    Chromosomal localization of the large subunit of mouse replication factor C in the mouse and human

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47015/1/335_2004_Article_BF00350900.pd
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