177,261 research outputs found
An sl(4,R) Lie algebraic approach to the Bargmann functions and its application to the second Poschl-Teller equation
No full textThe sl(4,R) Lie algebraic treatment of the Winger SU(2) matrices (1959) is extended by analytical continuation to the Bargmann SU(1,1) matrices (1947) corresponding to the positive discrete series irreducible representations. It is then used to obtain an sl(4,R) dynamical potential algebra for the negative-energy solutions of the second Poschl-Teller equations (1933).SCOPUS: re.jinfo:eu-repo/semantics/publishe
So(3, 1) versus sp(4,R) as dynamical potential algebra of the symmetrical Poschl-Teller potentials
No full textThe results of a previous paper (ibid. vol.21 p.4487, 1988), concerned with the first family of two-parameter Poschl-Teller potentials, are used to obtain potential and dynamical potential algebras for the subfamily of one-parameter symmetrical Poschl-Teller potentials. They are respectively identified with so(3) and so(3, 1) algebras, and shown to be subalgebras of the so(4) potential and sl(4, R) dynamical potential algebras of the two-parameter potentials. All the Hamiltonian eigenstates, corresponding to the subfamily of potentials with quantised potential strengths mu differing by an integer, are proved to belong to a single degenerate continuous unitary irreducible representation of so(3, 1), which may be labelled by generalised Young pattern labels ( omega 0), where omega =- 1+1/4i eta ,and eta is some real parameter. An sp(4, R) approximately=so(3, 2) algebra is also constructed and shown to provide an alternative choice for the dynamical potential algebra of the symmetrical potentials. All the above-mentioned eigenstates belong to a single sp(4, R) unitary irreducible representation of the positive discrete series, which may be labelled by its lowest weight (1/2 1/2). Such an alternative choice for the dynamical potential algebra, however, does not lead to a unified treatment of the one- and two-parameter potentials as does the first one.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
An sl(4,R) Lie algebraic treatment of the first family of Poschl-Teller potentials
No full textAn s1(4,ℝ) dynamical potential algebra, containing the so(4) potential algebra, is constructed for the two-parameter Poschl-Teller potentials of the first kind. For this purpose, the relation between the Wigner rotation matrices and the solutions of the first Poschl-Teller equation is used. Explicit expressions are given for the s1(4,ℝ) generators, as well as for their action on the normalised solutions. All the Hamiltonian eigenstates, corresponding to the family of potentials with quantised potential strengths (m′,m) differing by integers, are proved to belong to a single s1(4,ℝ) unitary irreducible representation of the ladder series. For integral values of m′ and m, the latter is Iludd(0, 0; η), while, for half-integral values, it is Iladd(1/2, 1/2 η), where η is some real parameter. Both irreducible representations are also shown to be characterised by generalised Young pattern labels [pqrO], where p = -2 -1/2iη, and q = r = 0. © 1988 IOP Publishing Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Temporally stable coherent states for infinite well and Poschl-Teller potentials
No full textThis article is a direct illustration of a construction of coherent states which has been recently proposed by two of us (JPG and JK). We have chosen the example of a particle trapped in an infinite square-well and also in Poschl-Teller potentials of the trigonometric type. In the construction of the corresponding coherent states, we take advantage of the simplicity of the solutions, which ultimately stems from the fact they share a common SU(1,1) symmetry a la Barut-Girardello. Many properties of these states are then studied, both from mathematical and from physical points of view. (C) 2001 American Institute of Physics
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Relativistic symmetries with the trigonometric Poschl-Teller potential plus Coulomb-like tensor interaction
No full textThe Dirac equation is solved to obtain its approximate bound states for a spin-1/2 particle in the presence of trigonometric Poschl-Teller (tPT) potential including a Coulomb-like tensor interaction with arbitrary spin-orbit quantum number kappa using an approximation scheme to substitute the centrifugal terms kappa(kappa +/- 1)r(-2). In view of spin and pseudo- spin (p-spin) symmetries, the relativistic energy eigenvalues and the corresponding two-component wave functions of a particle moving in the field of attractive and repulsive tPT potentials are obtained using the asymptotic iteration method (AIM). We present numerical results in the absence and presence of tensor coupling A and for various values of spin and p-spin constants and quantum numbers n and kappa. The non-relativistic limit is also obtained
Approximate Dirac solutions of a complex parity-time-symmetric Poschl-Teller potential in view of spin and pseudospin symmetries
No full textBy employing an exponential-type approximation scheme to replace the centrifugal term, we have approximately solved the Dirac equation for a spin-1/2 particle subjected to complex parity-time-symmetric scalar and vector Poschl-Teller (PT) potentials with arbitrary spin-orbit kappa-wave states in view of spin and pseudospin (p-spin) symmetries. The real bound-state energy eigenvalue equation and the corresponding two-spinor components wave function expressible in terms of hypergeometric functions are obtained by means of wave function analysis. The spin-kappa Dirac equation and the spin-0 Klein-Gordon equation with complex PT potentials share the same energy spectrum under the choice of S(r) = +/- V(r) (i.e. exact spin and p-spin symmetries)
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