17,661 research outputs found

    Realization of the Optimal Universal Quantum Entangler

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    We present the first experimental demonstration of the ''optimal'' and ''universal'' quantum entangling process involving qubits encoded in the polarization of single photons. The structure of the ''quantum entangling machine'' consists of the quantum injected optical parametric amplifier by which the contextual realization of the 1->2 universal quantum cloning and of the universal NOT (U-NOT) gate has also been achieved.Comment: 10 pages, 3 figures, to appear in Physical Review

    Quantum Preferred Frame: Does It Really Exist?

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    The idea of the preferred frame as a remedy for difficulties of the relativistic quantum mechanics in description of the non-local quantum phenomena was undertaken by such physicists as J. S. Bell and D. Bohm. The possibility of the existence of preferred frame was also seriously treated by P. A. M. Dirac. In this paper, we propose an Einstein-Podolsky-Rosen-type experiment for testing the possible existence of a quantum preferred frame. Our analysis suggests that to verify whether a preferred frame of reference in the quantum world exists it is enough to perform an EPR type experiment with pair of observers staying in the same inertial frame and with use of the massive EPR pair of spin one-half or spin one particles.Comment: 5 pp., 6 fig

    Risk and reliability assessment of future power systems

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    Liberalisation of electricity markets, changing patterns in the generation and use of electricity, and new technologies are some of the factors that result in increased uncertainty about the future operating requirements of an electric power system. In this context, planning for future investments in a power system requires careful consideration of risk and reliability, and of the metrics with which these are measured. This paper highlights the need for consideration of a broader class of approaches to risk and reliability that have hitherto tended not to be an explicit part of the system development process in the electricity industry. We discuss a high level conceptual model that shows sources of uncertainty and modes of control for system operators and planners and offers a broad-brush approach to highlight risks at the planning stage. We argue that there is a need for new risk-informed criteria to help evaluate the necessary investments in electricity transmission systems. We further argue that the risk models that are developed for this purpose need to take better account of overall societal impact than is captured by traditional measures such as loss of load probability and loss of load expectation; societal impact should take account of frequencies of events with different levels of consequences, distinguishing, for example, between multiple small events and a single large event. This leads to discussion of a “disutility criterion” which has been previously studied in a health and safety context to distinguish between risk aversion and disaster aversion. This approach is new in the context of power systems

    Countering Social Engineering through Social Media: An Enterprise Security Perspective

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    The increasing threat of social engineers targeting social media channels to advance their attack effectiveness on company data has seen many organizations introducing initiatives to better understand these vulnerabilities. This paper examines concerns of social engineering through social media within the enterprise and explores countermeasures undertaken to stem ensuing risk. Also included is an analysis of existing social media security policies and guidelines within the public and private sectors.Comment: Proceedings of The 7th International Conference on Computational Collective Intelligence Technologies and Applications (ICCCI 2015), LNAI, Springer, Vol. 9330, pp. 54-6

    Partial Core Transformer for Energization of High Voltage Arc-Signs

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    paper T3-304A high voltage partial core resonating transformer has been designed and constructed such that its magnetising current reactance is matched to the reactive current drawn by the capacitance of an arc-sign. The supply only provides the real power losses of the transformer plus any reactive power mismatch between the magnetizing reactance and the capacitance of the arc-sign. A mathematical model of the transformer is developed using a reverse design modelling technique. The model is then used to design a 50Hz, 8kVA, 230V/80kV, partial core transformer to meet the required electrical demand of the load. The transformer was constructed and tested. The transformer successfully resonated with the load and provided 68VAr of compensation when operating at 10kV while being supplied from a domestic 230V, 10A, power outlet. The completed transformer has a finished weight of 69kg and has been successfully used for powering an arc-sign at an exhibition of electric sculptures

    Possible Experience: from Boole to Bell

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    Mainstream interpretations of quantum theory maintain that violations of the Bell inequalities deny at least either realism or Einstein locality. Here we investigate the premises of the Bell-type inequalities by returning to earlier inequalities presented by Boole and the findings of Vorob'ev as related to these inequalities. These findings together with a space-time generalization of Boole's elements of logic lead us to a completely transparent Einstein local counterexample from everyday life that violates certain variations of the Bell inequalities. We show that the counterexample suggests an interpretation of the Born rule as a pre-measure of probability that can be transformed into a Kolmogorov probability measure by certain Einstein local space-time characterizations of the involved random variables.Comment: Published in: EPL, 87 (2009) 6000
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