20,563 research outputs found

    Some aspects of analytical chemistry as applied to water quality assurance techniques for reclaimed water: The potential use of X-ray fluorescence spectrometry for automated on-line fast real-time simultaneous multi-component analysis of inorganic pollutants in reclaimed water

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    The potential use of isotopically excited energy dispersive X-ray fluorescence (XRF) spectrometry for automated on line fast real time (5 to 15 minutes) simultaneous multicomponent (up to 20) trace (1 to 10 parts per billion) analysis of inorganic pollutants in reclaimed water was examined. Three anionic elements (chromium 6, arsenic and selenium) were studied. The inherent lack of sensitivity of XRF spectrometry for these elements mandates use of a preconcentration technique and various methods were examined, including: several direct and indirect evaporation methods; ion exchange membranes; selective and nonselective precipitation; and complexation processes. It is shown tha XRF spectrometry itself is well suited for automated on line quality assurance, and can provide a nondestructive (and thus sample storage and repeat analysis capabilities) and particularly convenient analytical method. Further, the use of an isotopically excited energy dispersive unit (50 mCi Cd-109 source) coupled with a suitable preconcentration process can provide sufficient sensitivity to achieve the current mandated minimum levels of detection without the need for high power X-ray generating tubes

    Quantum Nonlocality of N-qubit W states

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    An experimental setup for testing quantum nonlocality of N qubits is proposed. This method is a generalization of the optical setup proposed by Banaszek and Wodkiewicz [1]. The quantum nonlocality of N qubits can be obtained through its violation of N-qubit Bell inequalities. The correlation function measured in the experiment is described by the Wigner function. The effect of inefficient detector is also considered.Comment: 5 pages and 2 figures, some errors are corrected in v

    Worldliness: how do we live with others? Universality-as-multiplicity

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    The ifa conference "Cultures of We" held on 13 September 2017 in Berlin cut to the core of world politics today. It asked: How can we stay true to the principle of equality, as enshrined in the Universal Declaration of Human Rights (UDHR), when "othering" has resurged in identity and politics validated by a newly-vocal narrative of "us versus them?" Populist movements formalized by Brexit in the United Kingdom in June 2016 and the election of Donald J. Trump to the US presidency five months later march in lock-step with other racist-nationalist regimes in the Philippines, Turkey, Austria, and so on. Many pockets of Scandinavia, previously models of liberal tolerance, also exhibit similar sympathies. Renewed commitment to the UDHR will not suffice, I’m afraid. Its insistence on singularity to convey universality sinks the proposition

    Continuous Multipartite Entangled State in Wigner Representation and the Violation of Zukowski-Brukner Inequality

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    We construct an explicit Wigner function for N-mode squeezed state. Based on a previous observation that the Wigner function describes correlations in the joint measurement of the phase-space displaced parity operator, we investigate the non-locality of multipartite entangled state by the violation of Zukowski-Brukner N-qubit Bell inequality. We find that quantum predictions for such squeezed state violate these inequalities by an amount that grows with the number N.Comment: 5 pages, rewritten version, accepted by Phys. Rev.

    Quantum contextuality for a relativistic spin-1/2 particle

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    The quantum predictions for a single nonrelativistic spin-1/2 particle can be reproduced by noncontextual hidden variables. Here we show that quantum contextuality for a relativistic electron moving in a Coulomb potential naturally emerges if relativistic effects are taken into account. The contextuality can be identified through the violation of noncontextuality inequalities. We also discuss quantum contextuality for the free Dirac electron as well as the relativistic Dirac oscillator.Comment: REVTeX4, 5 page

    Violating Bell Inequalities Maximally for Two dd-Dimensional Systems

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    We investigate the maximal violation of Bell inequalities for two dd-dimensional systems by using the method of Bell operator. The maximal violation corresponds to the maximal eigenvalue of the Bell operator matrix. The eigenvectors corresponding to these eigenvalues are described by asymmetric entangled states. We estimate the maximum value of the eigenvalue for large dimension. A family of elegant entangled states Ψ>app|\Psi>_{\rm app} that violate Bell inequality more strongly than the maximally entangled state but are somewhat close to these eigenvectors is presented. These approximate states can potentially be useful for quantum cryptography as well as many other important fields of quantum information.Comment: 6 pages, 1 figure. Revised versio

    Bell inequalities for three particles

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    We present tight Bell inequalities expressed by probabilities for three four- and five-dimensional systems. The tight structure of Bell inequalities for three dd-dimensional systems (qudits) is proposed. Some interesting Bell inequalities of three qubits reduced from those of three qudits are also studied.Comment: 8 pages, 3 figures. Accepted for publication in Phys. Rev.
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