124 research outputs found

    Strain Localisation, Fracturing and Hydrothermal Mineralisation: Numerical Models of the Mount Isa Copper Deposit, Australia

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    There is substantial need in mineral exploration to understand the structural controls on ore deposition for these types of deposits in order to predict the localities of new ones. Application of basic principles of rock mechanics, and numerical simulations of deformation and fluid flow processes provide fundamental insights to Proterozoic hydrothermal mineralization atMount Isa, Australia. The rheology of layered meta-sedimentary rocks, and the orientation and position of these layered rocks relative to major fault systems were the key controls on ore deposition...conferenc

    Formation of Porous ZnO Nanosystems for Potential Use in Sensor Electronics

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    The semiconducting ZnO is a very promising material for applications in UV light emitters, optical de-tectors, solar cells, piezoelectric transducers, transparent electronics, gas sensors etc. It is known that physical properties, and as a result areas of applications, are strongly determined by morphology and size of the material’s structural elements. Therefore, the development of a technology that allows formation of nanoporous metal oxide structures with a high surface to volume ratio is of great interest nowadays. The aim of this work was to develop technology for selective formation of porous ZnO nanosystems and to de-termine the relationship between morphological characteristics of the layers obtained and their optical and electrical sensor properties with the aim of potential applications in optoelectronics and sensor electronics. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

    Formation of Porous ZnO Nanosystems for Potential Use in Sensor Electronics

    Get PDF
    The semiconducting ZnO is a very promising material for applications in UV light emitters, optical de-tectors, solar cells, piezoelectric transducers, transparent electronics, gas sensors etc. It is known that physical properties, and as a result areas of applications, are strongly determined by morphology and size of the material’s structural elements. Therefore, the development of a technology that allows formation of nanoporous metal oxide structures with a high surface to volume ratio is of great interest nowadays. The aim of this work was to develop technology for selective formation of porous ZnO nanosystems and to de-termine the relationship between morphological characteristics of the layers obtained and their optical and electrical sensor properties with the aim of potential applications in optoelectronics and sensor electronics. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

    A Path Integral Approach To Noncommutative Superspace

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    A path integral formula for the associative star-product of two superfields is proposed. It is a generalization of the Kontsevich-Cattaneo-Felder's formula for the star-product of functions of bosonic coordinates. The associativity of the star-product imposes certain conditions on the background of our sigma model. For generic background the action is not supersymmetric. The supersymmetry invariance of the action constrains the background and leads to a simple formula for the star-product.Comment: Latex 13 pages. v2: references and footnotes adde

    The quantum dynamic capacity formula of a quantum channel

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    The dynamic capacity theorem characterizes the reliable communication rates of a quantum channel when combined with the noiseless resources of classical communication, quantum communication, and entanglement. In prior work, we proved the converse part of this theorem by making contact with many previous results in the quantum Shannon theory literature. In this work, we prove the theorem with an "ab initio" approach, using only the most basic tools in the quantum information theorist's toolkit: the Alicki-Fannes' inequality, the chain rule for quantum mutual information, elementary properties of quantum entropy, and the quantum data processing inequality. The result is a simplified proof of the theorem that should be more accessible to those unfamiliar with the quantum Shannon theory literature. We also demonstrate that the "quantum dynamic capacity formula" characterizes the Pareto optimal trade-off surface for the full dynamic capacity region. Additivity of this formula simplifies the computation of the trade-off surface, and we prove that its additivity holds for the quantum Hadamard channels and the quantum erasure channel. We then determine exact expressions for and plot the dynamic capacity region of the quantum dephasing channel, an example from the Hadamard class, and the quantum erasure channel.Comment: 24 pages, 3 figures; v2 has improved structure and minor corrections; v3 has correction regarding the optimizatio

    Perfect state distinguishability and computational speedups with postselected closed timelike curves

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    Bennett and Schumacher's postselected quantum teleportation is a model of closed timelike curves (CTCs) that leads to results physically different from Deutsch's model. We show that even a single qubit passing through a postselected CTC (P-CTC) is sufficient to do any postselected quantum measurement, and we discuss an important difference between "Deutschian" CTCs (D-CTCs) and P-CTCs in which the future existence of a P-CTC might affect the present outcome of an experiment. Then, based on a suggestion of Bennett and Smith, we explicitly show how a party assisted by P-CTCs can distinguish a set of linearly independent quantum states, and we prove that it is not possible for such a party to distinguish a set of linearly dependent states. The power of P-CTCs is thus weaker than that of D-CTCs because the Holevo bound still applies to circuits using them regardless of their ability to conspire in violating the uncertainty principle. We then discuss how different notions of a quantum mixture that are indistinguishable in linear quantum mechanics lead to dramatically differing conclusions in a nonlinear quantum mechanics involving P-CTCs. Finally, we give explicit circuit constructions that can efficiently factor integers, efficiently solve any decision problem in the intersection of NP and coNP, and probabilistically solve any decision problem in NP. These circuits accomplish these tasks with just one qubit traveling back in time, and they exploit the ability of postselected closed timelike curves to create grandfather paradoxes for invalid answers.Comment: 15 pages, 4 figures; Foundations of Physics (2011

    Star products made (somewhat) easier

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    We develop an approach to the deformation quantization on the real plane with an arbitrary Poisson structure which based on Weyl symmetrically ordered operator products. By using a polydifferential representation for deformed coordinates x^j\hat x^j we are able to formulate a simple and effective iterative procedure which allowed us to calculate the fourth order star product (and may be extended to the fifth order at the expense of tedious but otherwise straightforward calculations). Modulo some cohomology issues which we do not consider here, the method gives an explicit and physics-friendly description of the star products.Comment: 20 pages, v2, v3: comments and references adde

    Diagnostic accuracy of the response to the brief tachycardia provoked by standing in children suspected for long QT syndrome

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    BACKGROUND Adult long QT syndrome (LQTS) patients have inadequate corrected QT interval (QTc) shortening and an abnormal T-wave response to the sudden heart rate acceleration provoked by standing. In adults, this knowledge can be used to aid an LQTS diagnosis and, possibly, for risk stratification. However, data on the diagnostic value of the standing test in children are currently limited. OBJECTIVE To determine the potential value of the standing test to aid LQTS diagnostics in children. METHODS In a prospective cohort including children (= 490 ms after standing only slightly increased sensitivity (91%, 95% confidence interval [CI]: 80%-98%) and slightly decreased specificity (58%, 95% CI: 47%-70%). Sensitivity increased slightly more when T-wave abnormalities were present (94%, 95% CI: 82%-99%; specificity 53%, 95% CI: 42%-65%). When a baseline QTc >= 440 ms was accompanied by a QTc >= 490 ms and T-wave abnormalities after standing, sensitivity further increased (96%, 95% CI: 85%-99%) at the expense of a further specificity decrease (41%, 95% CI: 30%-52%). Beat-to-beat analysis showed that 30 seconds after standing, LQTS children had a greater increase in heart rate compared to controls, which was more evidently present in LQTS boys and LQTS type 1 children. CONCLUSION In children, the standing test has limited additive diagnostic value for LQTS over a baseline electrocardiogram, while T-wave abnormalities after standing also have limited additional value. The standing test for LQTS should only be used with caution in children.Developmen

    Sequential, successive, and simultaneous decoders for entanglement-assisted classical communication

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    Bennett et al. showed that allowing shared entanglement between a sender and receiver before communication begins dramatically simplifies the theory of quantum channels, and these results suggest that it would be worthwhile to study other scenarios for entanglement-assisted classical communication. In this vein, the present paper makes several contributions to the theory of entanglement-assisted classical communication. First, we rephrase the Giovannetti-Lloyd-Maccone sequential decoding argument as a more general "packing lemma" and show that it gives an alternate way of achieving the entanglement-assisted classical capacity. Next, we show that a similar sequential decoder can achieve the Hsieh-Devetak-Winter region for entanglement-assisted classical communication over a multiple access channel. Third, we prove the existence of a quantum simultaneous decoder for entanglement-assisted classical communication over a multiple access channel with two senders. This result implies a solution of the quantum simultaneous decoding conjecture for unassisted classical communication over quantum multiple access channels with two senders, but the three-sender case still remains open (Sen recently and independently solved this unassisted two-sender case with a different technique). We then leverage this result to recover the known regions for unassisted and assisted quantum communication over a quantum multiple access channel, though our proof exploits a coherent quantum simultaneous decoder. Finally, we determine an achievable rate region for communication over an entanglement-assisted bosonic multiple access channel and compare it with the Yen-Shapiro outer bound for unassisted communication over the same channel.Comment: 33 pages, 2 figures; v2 contains a proof of the quantum simultaneous decoding conjecture for two-sender quantum multiple access channels; v3 shows how to recover the known unassisted and assisted quantum communication regions with a coherent quantum simultaneous decode
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