5,063 research outputs found

    Deformation of generic submanifolds in a complex manifold

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    This paper shows that an arbitrary generic submanifold in a complex manifold can be deformed into a 1-parameter family of generic submanifolds satisfying strong nondegeneracy conditions. The proofs use a careful analysis of the jet spaces of embeddings satisfying certain nondegeneracy properties, and also make use of the Thom transversality theorem, as well as the stratification of real-algebraic sets. Optimal results on the order of nondegeneracy are given.Comment: 24 page

    Artificial Intelligence as a Culturological Problem

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    The article poses the question of cultural interpretation of artificial intelligence. It is revealed that in relation to artificial intelligence in modern culture there are at least two conflicting strategies. The first strategy is based on the idea of the superiority of artificial intelligence over the human intellect, and as a response serves as a breeding ground for the ideas of techno-apocalypse. The second strategy, which arose and developed within the framework of the Soviet Information Society project, sees in artificial intelligence the possibility of building a more perfect and just society.     Keywords: information society, artificial intelligence, induction of artificial intelligence, cultural problem, intercultural spac

    Quantitative Simulation of the Superconducting Proximity Effect

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    A numerical method is developed to calculate the transition temperature of double or multi-layers consisting of films of super- and normal conductors. The approach is based on a dynamic interpretation of Gorkov's linear gap equation and is very flexible. The mean free path of the different metals, transmission through the interface, ratio of specular reflection to diffusive scattering at the surfaces, and fraction of diffusive scattering at the interface can be included. Furthermore it is possible to vary the mean free path and the BCS interaction NV in the vicinity of the interface. The numerical results show that the normalized initial slope of an SN double layer is independent of almost all film parameters except the ratio of the density of states. There are only very few experimental investigations of this initial slope and they consist of Pb/Nn double layers (Nn stands for a normal metal). Surprisingly the coefficient of the initial slope in these experiments is of the order or less than 2 while the (weak coupling) theory predicts a value of about 4.5. This discrepancy has not been recognized in the past. The autor suggests that it is due to strong coupling behavior of Pb in the double layers. The strong coupling gap equation is evaluated in the thin film limit and yields the value of 1.6 for the coefficient. This agrees much better with the few experimental results that are available. PACS: 74.45.+r, 74.62.-c, 74.20.F

    Experimental evidence of ageing and slow restoration of the weak-contact configuration in tilted 3D granular packings

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    Granular packings slowly driven towards their instability threshold are studied using a digital imaging technique as well as a nonlinear acoustic method. The former method allows us to study grain rearrangements on the surface during the tilting and the latter enables to selectively probe the modifications of the weak-contact fraction in the material bulk. Gradual ageing of both the surface activity and the weak-contact reconfigurations is observed as a result of repeated tilt cycles up to a given angle smaller than the angle of avalanche. For an aged configuration reached after several consecutive tilt cycles, abrupt resumption of the on-surface activity and of the weak-contact rearrangements occurs when the packing is subsequently inclined beyond the previous maximal tilting angle. This behavior is compared with literature results from numerical simulations of inclined 2D packings. It is also found that the aged weak-contact configurations exhibit spontaneous restoration towards the initial state if the packing remains at rest for tens of minutes. When the packing is titled forth and back between zero and near-critical angles, instead of ageing, the weak-contact configuration exhibits "internal weak-contact avalanches" in the vicinity of both the near-critical and zero angles. By contrast, the stronger-contact skeleton remains stable

    Josephson π\pi-state in superconductor-Luttinger liquid hybrid systems

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    Josephson current through a Luttinger liquid (LL) under a magnetic field is theoretically studied. We derive an analytical expression of Josephson current for clean interfaces, by using quasiclassical Green's function and functional bosonization procedure. We show that critical currents can be renormalized by electron-electron interactions at perfect transparency when LL is adiabatically connected with superconductors. We also find that a generation of π\pi-state, due to spin-dependent energy shift in Andreev bound states (ABS), is prohibited even at zero temperature when the strength of repulsive interactions reaches some critical value. The suppression of π\pi-state is caused by the low energy fluctuations propagating in LL, and making the Zeeman splitting in ABS blurred.Comment: 5 pages, 4figure

    The textbooks on conflictology: philosophers, animals and prehistoric art

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    В статье рассматривается проблема расширения значения понятия конфликт за счет неоправданной экстраполяции в учебники по конфликтологии философского, этологического и культурологического материала.The article deals with the problem of expanding the meaning of the conflict. The extension of the philosophical, ethological and cultural material in the book on conflict is declared invalid

    Severe discrepancies between experiment and theory in the superconducting proximity effect

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    The superconducting proximity effect is investigated for SN double layers in a regime where the resulting transition temperature T_{c} does not depend on the mean free paths of the films and, within limits, not on the transparency of the interface. This regime includes the thin film limit and the normalized initial slope S_{sn}= (d_{s}/T_{s})|dT_{c}/dd_{n}|. The experimental results for T_{c} are compared with a numerical simulation which was recently developed in our group. The results for the SN double layers can be devided into three groups: (i) When N = Cu, Ag, Au, Mg a disagreement between experiment and theory by a factor of the order of three is observed, (ii) When N = Cd, Zn, Al the disagreement between experiment and theory is reduced to a factor of about 1.5, (iii) When N = In, Sn a reasonably good agreement between experiment and theory is observed
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