915 research outputs found
On the Laplace transform of the Fr\'{e}chet distribution
We calculate exactly the Laplace transform of the Fr\'{e}chet distribution in
the form , , , for arbitrary rational values of the shape parameter , i.e.
for with . 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
We study integral representation of so-called -dimensional Catalan numbers
, defined by , , . We prove that the 's are the th Hausdorff
power moments of positive functions defined on . We
construct exact and explicit forms of and demonstrate that they can
be expressed as combinations of hypergeometric functions of type
of argument . These solutions are unique. We analyse
them analytically and graphically. A combinatorially relevant, specific
extension of for even in the form is
analyzed along the same lines.Comment: comments added, two new references adde
Exact and explicit evaluation of Brezin-Hikami kernels
We present exact and explicit form of the kernels 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 '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
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
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
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
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
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
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
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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