987 research outputs found

    The Ramanujan master theorem and its implications for special functions

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    We study a number of possible extensions of the Ramanujan master theorem, which is formulated here by using methods of Umbral nature. We discuss the implications of the procedure for the theory of special functions, like the derivation of formulae concerning the integrals of products of families of Bessel functions and the successive derivatives of Bessel type functions. We stress also that the procedure we propose allows a unified treatment of many problems appearing in applications, which can formally be reduced to the evaluation of exponential- or Gaussian-like integrals.Comment: 12 page

    Definite integrals and operational methods

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    An operatorial method, already employed to formulate a generalization of the Ramanujan master theorem, is applied to the evaluation of integrals of various type. This technique provide a very flexible and powerful tool yielding new results encompassing various aspects of the special function theory.Comment: 9 pages; minor changes to match published versio

    Operator solutions for fractional Fokker-Planck equations

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    We obtain exact results for fractional equations of Fokker-Planck type using evolution operator method. We employ exact forms of one-sided Levy stable distributions to generate a set of self-reproducing solutions. Explicit cases are reported and studied for various fractional order of derivatives, different initial conditions, and for different versions of Fokker-Planck operators.Comment: 4 pages, 3 figure

    Spectral density of generalized Wishart matrices and free multiplicative convolution

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    We investigate the level density for several ensembles of positive random matrices of a Wishart--like structure, W=XXW=XX^{\dagger}, where XX stands for a nonhermitian random matrix. In particular, making use of the Cauchy transform, we study free multiplicative powers of the Marchenko-Pastur (MP) distribution, MPs{\rm MP}^{\boxtimes s}, which for an integer ss yield Fuss-Catalan distributions corresponding to a product of ss independent square random matrices, X=X1XsX=X_1\cdots X_s. New formulae for the level densities are derived for s=3s=3 and s=1/3s=1/3. Moreover, the level density corresponding to the generalized Bures distribution, given by the free convolution of arcsine and MP distributions is obtained. We also explain the reason of such a curious convolution. The technique proposed here allows for the derivation of the level densities for several other cases.Comment: 10 latex pages including 4 figures, Ver 4, minor improvements and references updat
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