15,031 research outputs found

    On the Zitterbewegung Transient Regime in a Coarse-Grained Space-Time

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    In the present contribution, by studying a fractional version of Dirac's equation for the electron, we show that the phenomenon of Zitterbewegung in a coarse-grained medium exhibits a transient oscillatory behavior, rather than a purely oscillatory regime, as it occurs in the integer case, α=1\alpha=1. Our result suggests that, in such systems, the Zitterbewegung-type term related to a trembling motion of a quasiparticle is tamed by its complex interactions with other particles and the medium. This can justify the difficulties in the observation of this interesting phenomenon. The possibility that the Zitterbewegung be accompanied by a damping factor supports the viewpoint of particle substructures in Quantum Mechanics.Comment: 11 pages, 1 figure. This paper has been published in J. Adv. Phys. 7 (2015) 144

    Remarks on nonlinear Electrodynamics

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    We consider both generalized Born-Infeld and Exponential Electrodynamics. The field-energy of a point-like charge is finite only for Born-Infeld-like Electrodynamics. However, both Born-Infeld-type and Exponential Electrodynamics display the vacuum birefringence phenomenon. Subsequently, we calculate the lowest-order modifications to the interaction energy for both classes of Electrodynamics, within the framework of the gauge-invariant path-dependent variables formalism. These are shown to result in long-range (1/r51/r^5- type) corrections to the Coulomb potential. Once again, for their non-commutative versions, the interaction energy is ultraviolet finite.Comment: 10 pages. arXiv admin note: substantial text overlap with arXiv:1312.515

    Representing Roomates' Preferences with Symmetric Utilities

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    In the context of the stable roommates problem, it is shown that acyclicity of preferences is equivalent to the existence of symmetric utility functions, i.e. the utility of agent i when matched with j is the same as j 's utility when matched with i .

    Creativity and innovation: A contribution of behavioral economics

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    Innovation in products and services is seen by scholars, by specialized media in management, and by some managers as the main currency in modern economies. This is because it allows high average market profits, fame for innovators, or brand growth, for example. However, in practice, most managers still treat innovation as a secondary issue on their agendas. This problem results from the inability of market professionals to analyze people inside and outside their companies. It is not possible to develop innovative products in a systematic way without treating this point effectively. Moreover, in this process, creativity is a necessary, but not necessarily sufficient, condition to be fulfilled and requires behavioral transformation. In this context, it is believed that behavioral economics can make a sufficient contribution in the form of an analytical marketing tool by offering an analysis closer to human beings' reality, and, thus, allow a better understanding of people's behavior in the process of innovation in the market

    Topological Gravity on (D,N)(D,N)-Shift Superspace Formulation

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    In this contribution, we re-assess the subject of topological gravity by following the Shift Supersymmetry formalism. The gauge-fixing of the theory goes under the Batallin-Vilkovisky (BV) prescription based on a diagram that contains both ghost and anti-ghost superfields, associated to the super-vielbein and the super-Lorentz connection. We extend the formulation of the topological gravity action to an arbitrary number of dimensions of the shift superspace by adopting a formulation based on the gauge-fixing for BF-type models

    The Correlation Matrix of the Brazilian Central Bank's Standard Model for Interest Rate Market Risk

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    Central Bank of Brazil is implementing a Value At Risk (V.A.R.) methodology to establish minimum capital requirements for financial institutions to bear market risk derived from interest rate fluctuations. This article shows that the construction of the correlation matrix of the Brazilian Central Bank's Standard Model for Interest Rate is coherent, in the sense it is positive defined.
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