120 research outputs found

    Nonequilibrium transport and statistics of Schwinger pair production in Weyl semimetals

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    The non-equilibrium dynamics beyond linear response of Weyl semimetals is studied after a sudden switching on of a DC electric field. The resulting current is a nonmonotonic function of time, with an initial quick increase of polarization current followed by a power-law decay. Particle-hole creation \`a la Schwinger dominates for long times when the conduction current takes over the leading role, with the total current increasing again. The conductivity estimated from a dynamical calculation within a Drude picture agrees with the one obtained from Kubo's formula. The full distribution function of electron-hole pairs changes from Poissonian for short perturbations to a Gaussian in the long perturbation (Landau-Zener) regime. The vacuum persistence probability of high energy physics manifests itself in a finite probability of no pair creation and no induced current at all times.Comment: 7 pages, 4 figure

    Analytical drain‐current model of p‐ and n‐channel OTFTs for circuit simulation

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    Organic thin-film transistors (OTFTs) are an emerging technology for large scale circuit integration, owing the availability of both p- and n- channel devices. For the technology development and the design of circuits and digital systems, the accurate physical modeling is mandatory. In this work we propose an unified analytical model for both p- and n- type OTFTs. The model is physically based and accounts for a double exponential density of states (DOS). It is simple, symmetric and accurately describes the below-threshold, linear, and saturation regimes via a unique formulation. The model is eventually validated with the measurements of complementary OTFTs fabricated in a fullyprinted technolog

    Dynamics of conflicts in Wikipedia

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    In this work we study the dynamical features of editorial wars in Wikipedia (WP). Based on our previously established algorithm, we build up samples of controversial and peaceful articles and analyze the temporal characteristics of the activity in these samples. On short time scales, we show that there is a clear correspondence between conflict and burstiness of activity patterns, and that memory effects play an important role in controversies. On long time scales, we identify three distinct developmental patterns for the overall behavior of the articles. We are able to distinguish cases eventually leading to consensus from those cases where a compromise is far from achievable. Finally, we analyze discussion networks and conclude that edit wars are mainly fought by few editors only.Comment: Supporting information adde

    A Generalization Technique for Nearest-Neighbor Classifiers

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    Computer Recognition of Hand-Written Characters using the Distance Transform

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    Adaptive Voting Rules fo k-NN Classifiers

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    Co-operative Classifiers for High Quality Handprinted Character Recognition

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