822 research outputs found
Second order superintegrable systems in conformally flat spaces. IV. The classical 3D Stäckel transform and 3D classification theory
This article is one of a series that lays the groundwork for a structure and classification theory of second order superintegrable systems, both classical and quantum, in conformally flat spaces. In the first part of the article we study the Stäckel transform (or coupling constant metamorphosis) as an invertible mapping between classical superintegrable systems on different three-dimensional spaces. We show first that all superintegrable systems with nondegenerate potentials are multiseparable and then that each such system on any conformally flat space is Stäckel equivalent to a system on a constant curvature space. In the second part of the article we classify all the superintegrable systems that admit separation in generic coordinates. We find that there are eight families of these systems
The Applicability of Management by Objectives to the Administration of Municipal Parks and Recreation
It seems that most everyone these days is interested in, and demanding better and more effective management from the public sector. After serious deceptions at the highest level of government in the early 1970\u27s, citizens are somewhat more demanding in the accountability of government institutions, and their representatives.
Public recreation managers are expeditiously seeking new administrative techniques and decision making models that will ultimately get things done while hopefully increasing respect for public management strategy and still enhance the humanistic elements of job (employee) satisfaction.
Management by objectives offers an opportunity to incorporate a systematic approach to organizational administration, increasing employee motivation, defining goals and offering a viable means for performance measurement
An Alternative to Matter Localization in the "Brane World": An Early Proposal and its Later Improvements
Here we place the Latex typeset of the paper M. Pavsic, Phys. Lett. A116
(1986) 1-5. In the paper we presented the picture that our spacetime is a
3-brane moving in a higher dimensional space. The dynamical equations were
derived from the action which is just that for the usual Dirac-Nambu-Goto
-brane. We also considered the case where not only one, but many branes of
various dimensionalities are present, and showed that their intersections with
the 3-brane manifest as matter in 4-dimensional spacetime. We considered a
particular case, where the intersections behaved as point particles, and found
out that they follow the geodesics on the 3-brane worldsheet (identified with
our spacetime). In a series of subsequent papers the original idea has been
further improved and developped. This is discussed in a note at the end, where
it is also pointed out that such a model resolves the problem of massive matter
confinement on the brane, recently discussed by Rubakov et al. and Mueck et al.Comment: 11 page
Generalized Chaplygin gas as geometrical dark energy
The generalized Chaplygin gas provides an interesting candidate for the
present accelerated expansion of the universe. We explore a geometrical
explanation for the generalized Chaplygin gas within the context of brane world
theories where matter fields are confined to the brane by means of the action
of a confining potential. We obtain the modified Friedmann equations,
deceleration parameter and age of the universe in this scenario and show that
they are consistent with the present observational data.Comment: 11 pages, 3 figures, to appear in PR
Chaplygin gas dominated anisotropic brane world cosmological models
We present exact solutions of the gravitational field equations in the
generalized Randall-Sundrum model for an anisotropic brane with Bianchi type I
geometry, with a generalized Chaplygin gas as matter source. The generalized
Chaplygin gas, which interpolates between a high density relativistic era and a
non-relativistic matter phase, is a popular dark energy candidate. For a
Bianchi type I space-time brane filled with a cosmological fluid obeying the
generalized Chaplygin equation of state the general solution of the
gravitational field equations can be expressed in an exact parametric form,
with the comoving volume taken as parameter. In the limiting cases of a stiff
cosmological fluid, with pressure equal to the energy density, and for a
pressureless fluid, the solution of the field equations can be expressed in an
exact analytical form. The evolution of the scalar field associated to the
Chaplygin fluid is also considered and the corresponding potential is obtained.
The behavior of the observationally important parameters like shear, anisotropy
and deceleration parameter is considered in detail.Comment: 13 pages, 6 figures, accepted for publication in PR
Quantum cosmological Friedman models with a massive Yang-Mills field
We prove the existence of a spectral resolution of the Wheeler-DeWitt
equation when the matter field is provided by a massive Yang-Mills field. The
resolution is achieved by first solving the free eigenvalue problem for the
gravitational field and then the constrained eigenvalue problem for the
Yang-Mills field. In the latter case the mass of the Yang-Mills field assumes
the role of the eigenvalue.Comment: 16 pages, v3: typos corrected, final version, to appear in CQ
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