173 research outputs found

    Dynamics of quantum entanglement in the reservoir with memory effects

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    The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects. The completely positive reduced dynamical map can be constructed in the Kraus representation. Quantum entanglement decays more slowly in the non-Markovian environment. The decoherence time for quantum entanglement can be markedly increased by the change of the memory kernel. It is found out that the entanglement sudden death between quantum systems and entanglement sudden birth between the system and reservoir occur at different instants.Comment: 14 pages, 3 figure

    Reversible magnetization of MgB2 single crystals with a two-gap nature

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    We present reversible magnetization measurements on MgB2 single crystals in magnetic fields up to 2.5 T applied parallel to the crystal's c-axis. This magnetization is analyzed in terms of the Hao-Clem model, and various superconducting parameters, such as the critical fields [Hc(0) and Hc2(0)], the characteristic lengths [xi(0) and lambda(0)], and the Ginzburg-Landau parameter, kappa, are derived. The temperature dependence of the magnetic penetration depth, lambda(T), obtained from the Hao-Clem analysis could not be explained by theories assuming a single gap. Our data are well described by using a two-gap model.Comment: 20 pages, 1 table, 4 figures, will be published in Phys. Rev.

    Born-Infeld Type Phantom Model in the ωω\omega-\omega' Plane

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    In this paper, we investigate the dynamics of Born-Infeld(B-I) phantom model in the ωω\omega-\omega' plane, which is defined by the equation of state parameter for the dark energy and its derivative with respect to NN(the logarithm of the scale factor aa). We find the scalar field equation of motion in ωω\omega-\omega' plane, and show mathematically the property of attractor solutions which correspond to ωϕ1\omega_\phi\sim-1, Ωϕ=1\Omega_\phi=1, which avoid the "Big rip" problem and meets the current observations well.Comment: 6 pages, 3 figures, some references adde

    The 6G Architecture Landscape:European Perspective

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    Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: A systematic analysis for the Global Burden of Disease Study 2015

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    Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding: Bill & Melinda Gates Foundation

    Dynamic clustering for imbalance management through local supply and demand balancing

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    The electrical power system has been facing a fundamental shift of paradigm with the integration of renewable energy sources (RES) and price responsive loads. These changes introduce higher uncertainties and pose implications for both network and market actors. While the network operators face frequent operational challenges in terms of voltage limit violations and network congestions, the market parties need deal with a higher risk of imbalance. In this paper, a dynamic clustering method has been proposed to procure flexibility from the smallscale residential prosumers in order to minimize the imbalance cost. An agent-based coordination mechanism has been adopted to implement a demand response program based on local supply and demand balancing. A bottom-up simulation analysis was performed incorporating 600 residential prosumers. Simulation results indicate that a dynamic and adaptive clustering scheme can efficiently minimize the imabalance cost resulting from wind power forecast errors while maintaining the comfort constraints of the prosumers

    Self-adaptive root-like capillary diffusion channels enabled by TaN/Zr3N4 nanomultilayered architecture: Achieving superior corrosion resistance

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    The combined merits of high hardness and superior chemical inertness enable transition metal nitrides (TMNs) to be extensively coated onto the metal surfaces for avoiding erosion and corrosion attacks. However, the relatively large-size through-type diffusion channels commonly appear in the corroded layers as TMNs coatings subjected to corrosive environments. These channels can serve as short-circuit-diffusion paths for corrosive ions and worsen the corrosion-resistance ability, eventually, yielding unpredictable failure due to the heterogeneous growth of corrosion products. Obviously, comparing with the large-size through-type diffusion channels, the biomimetic multi-forked root-like capillary channels can significantly extend the diffusion distance and retard the transportation of corrosive ions by continuously deflecting and refining the diffusion paths. Herein, the nano-laminated TaN/Zr3N4 architecture, consisting of alternating 10 nm-thickness c-TaN nanolayers and 2 nm-thickness N-rich o-Zr3N4 nanolayers, has been fabricated by magnetron sputtering technology; it exhibits the characteristic of c-TaN/c-Zr3N4 local coherent growth. Such TaN/Zr3N4 nanomultilayered structure contributes to the self-adaptive assembly of TaO2@ZrO2 core–shell nanostructure in the corroded layer, thereby yielding appearance of uniformly root-like capillary diffusion channels instead of the typical through-type diffusion channels in the constitute monolayers; finally, it achieves superior corrosion-resistance with homogeneously general corrosion rate and avoids the uncontrollable failures
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