915 research outputs found

    On the Laplace transform of the Fr\'{e}chet distribution

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    We calculate exactly the Laplace transform of the Fr\'{e}chet distribution in the form γx(1+γ)exp(xγ)\gamma x^{-(1+\gamma)} \exp(-x^{-\gamma}), γ>0\gamma > 0, 0x<0 \leq x < \infty, for arbitrary rational values of the shape parameter γ\gamma, i.e. for γ=l/k\gamma = l/k with l,k=1,2,l, k = 1,2, \ldots. The method employs the inverse Mellin transform. The closed form expressions are obtained in terms of Meijer G functions and their graphical illustrations are provided. A rescaled Fr\'{e}chet distribution serves as a kernel of Fr\'{e}chet integral transform. It turns out that the Fr\'{e}chet transform of one-sided L\'{e}vy law reproduces the Fr\'{e}chet distribution.Comment: 10 pages, 4 figures; one reference adde

    Multidimensional Catalan and related numbers as Hausdorff moments

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    We study integral representation of so-called dd-dimensional Catalan numbers Cd(n)C_{d}(n), defined by [p=0d1p!(n+p)!](dn)![\prod_{p=0}^{d-1} \frac{p!}{(n+p)!}] (d n)!, d=2,3,...d = 2, 3, ..., n=0,1,...n=0, 1, .... We prove that the Cd(n)C_{d}(n)'s are the nnth Hausdorff power moments of positive functions Wd(x)W_{d}(x) defined on x[0,dd]x\in[0, d^d]. We construct exact and explicit forms of Wd(x)W_{d}(x) and demonstrate that they can be expressed as combinations of d1d-1 hypergeometric functions of type d1Fd2_{d-1}F_{d-2} of argument x/ddx/d^d. These solutions are unique. We analyse them analytically and graphically. A combinatorially relevant, specific extension of Cd(n)C_{d}(n) for dd even in the form Dd(n)=[p=0d1p!(n+p)!][q=0d/21(2n+2q)!(2q)!]D_{d}(n)=[\prod_{p = 0}^{d-1} \frac{p!}{(n+p)!}] [\prod_{q = 0}^{d/2 - 1} \frac{(2 n + 2 q)!}{(2 q)!}] is analyzed along the same lines.Comment: comments added, two new references adde

    Exact and explicit evaluation of Brezin-Hikami kernels

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    We present exact and explicit form of the kernels hatK(x,y)hat{K}(x, y) appearing in the theory of energy correlations in the ensembles of Hermitian random matrices with Gaussian probability distribution, see E. Brezin and S. Hikami, Phys. Rev. E 57, 4140 and E 58, 7176 (1998). In obtaining this result we have exploited the analogy with the method of producing exact forms of two-sided, symmetric Levy stable laws, presented by us recently. This result is valid for arbitrary values of parameters in question. We furnish analytical and graphical representations of physical quantities calculated from hatK(x,y)hat{K}(x, y)'s.Comment: Improved presentation: two new figures added, two new appendices adde

    The Higher-Order Heat-Type Equations via signed L\'{e}vy stable and generalized Airy functions

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    We study the higher-order heat-type equation with first time and M-th spatial partial derivatives, M = 2, 3, ... . We demonstrate that its exact solutions for M even can be constructed with the help of signed Levy stable functions. For M odd the same role is played by a special generalization of Airy Ai function that we introduce and study. This permits one to generate the exact and explicit heat kernels pertaining to these equations. We examine analytically and graphically the spacial and temporary evolution of particular solutions for simple initial conditions.Comment: 11 pages, 6 figures; several typos correcte

    Generating Functions for Laguerre Polynomials: New Identities for Lacunary Series

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    We present a number of identities involving standard and associated Laguerre polynomials. They include double-, and triple-lacunary, ordinary and exponential generating functions of certain classes of Laguerre polynomials.Comment: The list a number of identities satisfied by standard Laguerre polynomials (3 pages

    Generation of coherent states of photon-added type via pathway of eigenfunctions

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    We obtain and investigate the regular eigenfunctions of simple differential operators x^r d^{r+1}/dx^{r+1}, r=1, 2, ... with the eigenvalues equal to one. With the help of these eigenfunctions we construct a non-unitary analogue of boson displacement operator which will be acting on the vacuum. In this way we generate collective quantum states of the Fock space which are normalized and equipped with the resolution of unity with the positive weight functions that we obtain explicitly. These states are thus coherent states in the sense of Klauder. They span the truncated Fock space without first r lowest-lying basis states: |0>, |1>, ..., |r-1>. These states are squeezed, are sub-Poissonian in nature and are reminiscent of photon-added states at Agarwal et al.Comment: 17 pages, 9 figure

    Repeated derivatives of composite functions and generalizations of the Leibniz rule

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    We use the properties of Hermite and Kamp\'e de F\'eriet polynomials to get closed forms for the repeated derivatives of functions whose argument is a quadratic or higher-order polynomial. The results we obtain are extended to product of functions of the above argument, thus giving rise to expressions which can formally be interpreted as generalizations of the familiar Leibniz rule. Finally, examples of practical interest are discussed.Comment: 10 pages, no figure

    Symbolic methods for the evaluation of sum rules of Bessel functions

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    The use of the umbral formalism allows a significant simplification of the derivation of sum rules involving products of special functions and polynomials. We rederive in this way known sum rules and addition theorems for Bessel functions. Furthermore, we obtain a set of new closed form sum rules involving various special polynomials and Bessel functions. The examples we consider are relevant for applications ranging from plasma physics to quantum optics.Comment: J. Math. Phys. vol. 54, 073501 (2013), 6 page

    The spherical Bessel and Struve functions and operational methods

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    We review some aspects of the theory of spherical Bessel functions and Struve functions by means of an operational procedure essentially of umbral nature, capable of providing the straightforward evaluation of their definite integrals and of successive derivatives. The method we propose allows indeed the formal reduction of these family of functions to elementary ones of Gaussian type. We study the problem in general terms and present a formalism capable of providing a unifying point of view including Anger and Weber functions too. The link to the multi-index Bessel functions is also briefly discussed

    Lacunary Generating Functions for the Laguerre Polynomials

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    Symbolic methods of umbral nature play an important and increasing role in the theory of special functions and in related fields like combinatorics. We discuss an application of these methods to the theory of lacunary generating functions for the Laguerre polynomials for which we give a number of new closed form expressions. We present furthermore the different possibilities offered by the method we have developed, with particular emphasis on their link to a new family of special functions and with previous formulations, associated with the theory of quasi monomials
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