12,645 research outputs found

    Adaptive Predictive Control Using Neural Network for a Class of Pure-feedback Systems in Discrete-time

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    10.1109/TNN.2008.2000446IEEE Transactions on Neural Networks1991599-1614ITNN

    Localization of strongly correlated electrons as Jahn-Teller polarons in manganites

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    A realistic modeling of manganites should include the Coulomb repulsion between ege_g electrons, the Hund's rule coupling to t2gt_{2g} spins, and Jahn-Teller phonons. Solving such a model by dynamical mean field theory, we report large magnetoresistances and spectra in good agreement with experiments. The physics of the unusual, insulating-like paramagnetic phase is determined by correlated electrons which are-due to strong correlations-easily trapped as Jahn-Teller polarons.Comment: 4 pages, 3 figure

    Pressure-induced metal-insulator transition in LaMnO3 is not of Mott-Hubbard type

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    Calculations employing the local density approximation combined with static and dynamical mean-field theories (LDA+U and LDA+DMFT) indicate that the metal-insulator transition observed at 32 GPa in paramagnetic LaMnO3 at room temperature is not a Mott-Hubbard transition, but is caused by orbital splitting of the majority-spin eg bands. For LaMnO3 to be insulating at pressures below 32 GPa, both on-site Coulomb repulsion and Jahn-Teller distortion are needed.Comment: 4 pages, 3 figure

    Influence of Correlated Disorder Potentials on the Levitation of Current Carrying States in the Quantum Hall Effect

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    The disorder driven quantum Hall to insulator transition is investigated for a two-dimensional lattice system. We consider a Gaussian correlated random potential, study the behaviour of the current carrying states and trace their energetical position when the disorder strength is increased. Our results qualitatively resemble those obtained previously for exponentially correlated disorder potentials. We find both the downward movement of the anti-Chern states as well as the floating up of the Chern states across the Landau gap which is sometimes masked by the global broadening of the tight binding band.Comment: 4 pages, 3 figures, EP2DS-14 Pragu

    A new Hardy–Mulholland-type inequality with a mixed kernel

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    By the use of weight coefficients and techniques of real analysis, we establish a new Hardy–Mulholland-type inequality with a mixed kernel and a best possible constant factor in terms of the hypergeometric function. Equivalent forms, an operator expression with the norm and reverses are also considered
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