oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Combinatorics of Boson Normal Ordering: the Dobinski Formula Revisited  [PDF]
Karol A. Penson,Allan I. Solomon
Mathematics , 2002,
Abstract: We derive explicit formulas for the normal ordering of powers of arbitrary monomials of boson operators. These formulas lead to generalisations of conventional Bell and Stirling numbers and to appropriate generalisations of the Dobinski relations. These new combinatorial numbers are shown to be coherent state matrix elements of powers of the monomials in question. It is further demonstrated that such Bell-type numbers, when considered as power moments, give rise to positive measures on the positive half-axis, which in many cases can be written in terms of known functions.
Exponential Operators, Dobinski Relations and Summability  [PDF]
P. Blasiak,A. Gawron,A. Horzela,K. A. Penson,A. I. Solomon
Physics , 2005, DOI: 10.1088/1742-6596/36/1/005
Abstract: We investigate properties of exponential operators preserving the particle number using combinatorial methods developed in order to solve the boson normal ordering problem. In particular, we apply generalized Dobinski relations and methods of multivariate Bell polynomials which enable us to understand the meaning of perturbation-like expansions of exponential operators. Such expansions, obtained as formal power series, are everywhere divergent but the Pade summation method is shown to give results which very well agree with exact solutions got for simplified quantum models of the one mode bosonic systems.
$ψ$-Poisson, $q$-Cigler, $ψ$-Dobinski, $ψ$-Rota and $ψ$-coherent states  [PDF]
A. K. Kwasniewski
Mathematics , 2004,
Abstract: Cigler simple derivation of usual and extended Dobinski formula is recalled and it is noted that both may be interpreted as averages of powers of random variables with the corresponding usual or extended Poisson distributions. In parallel more general formulas of extended operator umbral calculi origin are revealed . The formulas encompass both earlier cases as very specific ones.
Poisson, Dobinski, Rota and coherent states  [PDF]
A. K. Kwasniewski
Mathematics , 2004,
Abstract: New q- Dobinski formula might also be interpreted as the average of specific q-powers of random variable X with the usual Poisson distribution.
Hierarchical Dobinski-type relations via substitution and the moment problem  [PDF]
K. A. Penson,P. Blasiak,G. Duchamp,A. Horzela,A. I. Solomon
Mathematics , 2003, DOI: 10.1088/0305-4470/37/10/011
Abstract: We consider the transformation properties of integer sequences arising from the normal ordering of exponentiated boson ([a,a*]=1) monomials of the form exp(x (a*)^r a), r=1,2,..., under the composition of their exponential generating functions (egf). They turn out to be of Sheffer-type. We demonstrate that two key properties of these sequences remain preserved under substitutional composition: (a)the property of being the solution of the Stieltjes moment problem; and (b) the representation of these sequences through infinite series (Dobinski-type relations). We present a number of examples of such composition satisfying properties (a) and (b). We obtain new Dobinski-type formulas and solve the associated moment problem for several hierarchically defined combinatorial families of sequences.
Laguerre-type derivatives: Dobinski relations and combinatorial identities  [PDF]
K. A. Penson,P. Blasiak,A. Horzela,A. I. Solomon,G. H. E. Duchamp
Mathematics , 2009, DOI: 10.1063/1.3155380
Abstract: We consider properties of the operators D(r,M)=a^r(a^\dag a)^M (which we call generalized Laguerre-type derivatives), with r=1,2,..., M=0,1,..., where a and a^\dag are boson annihilation and creation operators respectively, satisfying [a,a^\dag]=1. We obtain explicit formulas for the normally ordered form of arbitrary Taylor-expandable functions of D(r,M) with the help of an operator relation which generalizes the Dobinski formula. Coherent state expectation values of certain operator functions of D(r,M) turn out to be generating functions of combinatorial numbers. In many cases the corresponding combinatorial structures can be explicitly identified.
Dobinski-type relations: Some properties and physical applications  [PDF]
P Blasiak,A Horzela,K A Penson,A I Solomon
Mathematics , 2005, DOI: 10.1088/0305-4470/39/18/015
Abstract: We introduce a generalization of the Dobinski relation through which we define a family of Bell-type numbers and polynomials. For all these sequences we find the weight function of the moment problem and give their generating functions. We provide a physical motivation of this extension in the context of the boson normal ordering problem and its relation to an extension of the Kerr Hamiltonian.
Dobinski-type relations and the Log-normal distribution  [PDF]
P. Blasiak,K. A. Penson,A. I. Solomon
Mathematics , 2003, DOI: 10.1088/0305-4470/36/18/101
Abstract: We consider sequences of generalized Bell numbers B(n), n=0,1,... for which there exist Dobinski-type summation formulas; that is, where B(n) is represented as an infinite sum over k of terms P(k)^n/D(k). These include the standard Bell numbers and their generalizations appearing in the normal ordering of powers of boson monomials, as well as variants of the "ordered" Bell numbers. For any such B we demonstrate that every positive integral power of B(m(n)), where m(n) is a quadratic function of n with positive integral coefficients, is the n-th moment of a positive function on the positive real axis, given by a weighted infinite sum of log-normal distributions.
q-Poisson, q-Dobinski, q-Rota and q-coherent states  [PDF]
A. K. Kwasniewski
Mathematics , 2004,
Abstract: q- Dobinski formula may be interpreted as the average of powers of a random variable X_q with the q- Poisson distribution.
Generalized uncertainty relations and coherent and squeezed states  [PDF]
D. A. Trifonov
Physics , 2000, DOI: 10.1364/JOSAA.17.002486
Abstract: Characteristic uncertainty relations and their related squeezed states are briefly reviewed and compared in accordance with the generalizations of three equivalent definitions of the canonical coherent states. The standard SU(1,1) coherent states are shown to be the unique states that minimize the Schroedinger uncertainty relation for every pair of the three generators and the Robertson relation for the three generators. The characteristic uncertainty inequalities are naturally extended to the case of several states. It is shown that these inequalities can be written in the equivalent complementary form.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.