12,224 research outputs found

    Bohmian mechanics in relativistic quantum mechanics, quantum field theory and string theory

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    I present a short overview of my recent achievements on the Bohmian interpretation of relativistic quantum mechanics, quantum field theory and string theory. This includes the relativistic-covariant Bohmian equations for particle trajectories, the problem of particle creation and destruction, the Bohmian interpretation of fermionic fields and the intrinsically Bohmian quantization of fields and strings based on the De Donder-Weyl covariant canonical formalism.Comment: 6 pages, talk given at Third International Workshop DICE2006, Piombino, Italy, September 11-15, 200

    A general-covariant concept of particles in curved background

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    A local current of particle density for scalar fields in curved background is constructed. The current depends on the choice of a two-point function. There is a choice that leads to local non-conservation of the current in a time-dependent gravitational background, which describes local particle production consistent with the usual global description based on the Bogoliubov transformation. Another choice, which might be the most natural one, leads to the local conservation of the current.Comment: 9 pages, the paper is modified such that it includes the corrections that will be published in the erratu

    D5D5-brane type I superstring background fields in terms of type IIB ones by canonical method and T-duality approach

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    We consider type IIB superstring theory with embedded D5D5-brane and choose boundary conditions which preserve half of the initial supersymmetry. In the canonical approach that we use, boundary conditions are treated as canonical constraints. The effective theory, obtained from the initial one on the solution of boundary conditions, has the form of the type I superstring theory with embedded D5D5-brane. We obtain the expressions for D5D5-brane background fields of type I theory in terms of the D5D5-brane background fields of type IIB theory. We show that beside known Ω\Omega even fields, they contain squares of Ω\Omega odd ones, where Ω\Omega is world-sheet parity transformation, Ω:σ→−σ\Omega:\sigma\to -\sigma. We relate result of this paper and the results of [1] using T-dualities along four directions orthogonal to D5D5-brane

    Practopoiesis: Or how life fosters a mind

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    The mind is a biological phenomenon. Thus, biological principles of organization should also be the principles underlying mental operations. Practopoiesis states that the key for achieving intelligence through adaptation is an arrangement in which mechanisms laying a lower level of organization, by their operations and interaction with the environment, enable creation of mechanisms lying at a higher level of organization. When such an organizational advance of a system occurs, it is called a traverse. A case of traverse is when plasticity mechanisms (at a lower level of organization), by their operations, create a neural network anatomy (at a higher level of organization). Another case is the actual production of behavior by that network, whereby the mechanisms of neuronal activity operate to create motor actions. Practopoietic theory explains why the adaptability of a system increases with each increase in the number of traverses. With a larger number of traverses, a system can be relatively small and yet, produce a higher degree of adaptive/intelligent behavior than a system with a lower number of traverses. The present analyses indicate that the two well-known traverses-neural plasticity and neural activity-are not sufficient to explain human mental capabilities. At least one additional traverse is needed, which is named anapoiesis for its contribution in reconstructing knowledge e.g., from long-term memory into working memory. The conclusions bear implications for brain theory, the mind-body explanatory gap, and developments of artificial intelligence technologies.Comment: Revised version in response to reviewer comment

    Type I background fields in terms of type IIB ones

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    We choose such boundary conditions for open IIB superstring theory which preserve N=1 SUSY. The explicite solution of the boundary conditions yields effective theory which is symmetric under world-sheet parity transformation Ω:σ→−σ\Omega:\sigma\to-\sigma. We recognize effective theory as closed type I superstring theory. Its background fields,beside known Ω\Omega even fields of the initial IIB theory, contain improvements quadratic in Ω\Omega odd ones.Comment: 4 revtex pages, no figure
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