686 research outputs found
Canonical Coherent States for the Relativistic Harmonic Oscillator
In this paper we construct manifestly covariant relativistic coherent states
on the entire complex plane which reproduce others previously introduced on a
given representation, once a change of variables unit disk is performed. We also introduce higher-order, relativistic
creation and annihilation operators, \C,\Cc, with canonical commutation
relation [\C,\Cc]=1 rather than the covariant one [\Z,\Zc]\approx Energy
and naturally associated with the group. The canonical (relativistic)
coherent states are then defined as eigenstates of \C. Finally, we construct
a canonical, minimal representation in configuration space by mean of
eigenstates of a canonical position operator.Comment: 11 LaTeX pages, final version, shortened and corrected, to appear in
J. Math. Phy
Development of a high altitude Stokes flow decelerator Final report
Drag generation theory, design, and drop tests for high altitude Stokes flow decelerato
On Schr\"odinger superalgebras
We construct, using the supersymplectic framework of Berezin, Kostant and
others, two types of supersymmetric extensions of the Schr\"odinger algebra
(itself a conformal extension of the Galilei algebra). An `-type' extension
exists in any space dimension, and for any pair of integers and . It
yields an superalgebra, which generalizes the N=1 supersymmetry
Gauntlett et al. found for a free spin-\half particle, as well as the N=2
supersymmetry of the fermionic oscillator found by Beckers et al. In two space
dimensions, new, `exotic' or `-type' extensions arise for each pair of
integers and , yielding an superalgebra of
the type discovered recently by Leblanc et al. in non relativistic Chern-Simons
theory. For the magnetic monopole the symmetry reduces to
\o(3)\times\osp(1/1), and for the magnetic vortex it reduces to
\o(2)\times\osp(1/2).Comment: On Schr\"odinger superalgebras, no figurs. Published versio
Generalized squeezed-coherent states of the finite one-dimensional oscillator and matrix multi-orthogonality
A set of generalized squeezed-coherent states for the finite u(2) oscillator
is obtained. These states are given as linear combinations of the mode
eigenstates with amplitudes determined by matrix elements of exponentials in
the su(2) generators. These matrix elements are given in the (N+1)-dimensional
basis of the finite oscillator eigenstates and are seen to involve 3x3 matrix
multi-orthogonal polynomials Q_n(k) in a discrete variable k which have the
Krawtchouk and vector-orthogonal polynomials as their building blocks. The
algebraic setting allows for the characterization of these polynomials and the
computation of mean values in the squeezed-coherent states. In the limit where
N goes to infinity and the discrete oscillator approaches the standard harmonic
oscillator, the polynomials tend to 2x2 matrix orthogonal polynomials and the
squeezed-coherent states tend to those of the standard oscillator.Comment: 18 pages, 1 figur
Fluiddynamik des Kammerwassers beim chronischen einfachen Glaukom: Mechanismen der Drucknormalisierung durch ein künstliches Abflusssystem
Zusammenfassung: Die Wechselwirkung zwischen Kräften, Verteilung und Absorption des Kammerwassers im subkonjunktivalen Gewebe wird anhand eines kürzlich publizierten theoretischen Modells untersucht, das die Produktion von Flüssigkeit im Auge und deren Eliminierung durch das Trabekelwerk, das uveosklerale Gewebe und einen Shunt beschreibt. Zielgröße dabei ist der intraokulare Druck. Die Mechanismen von neu geschaffenen Abflusswegen werden mithilfe der Theorie der porösen Medien dargestellt, die sich auf ein Sickerkissen beziehen, das unter dem subkonjunktivalen Gewebe liegt. Die rechnerische Analyse basiert auf der Geometrie und den Parametern, die das Zu- und Abflusssystem charakterisieren. Diese sind durch die Produktion von Kammerwasser, den chirurgisch angelegten Abflusskanal, sodann durch die Resorption in den episkleralen Gefäßen und durch die hydraulischen Eigenschaften des subkonjunktivalen Gewebes und des Sickerkissens sowie durch dessen Geometrie gegeben. Anhand parametrischer Untersuchungen können klinische Befunde physikalisch begründet werde
Structure and activity relationships for amine-based CO2 absorbents-II
A study to determine the structure and activity relationships of various amine-based CO2 absorbents was performed, in which the absorption of pure CO2 at atmospheric pressure was measured to assess the total absorption rates and capacities. Steric hindrance effect was noticed when side chain with alkyl group was present at the α-carbon to the amine group in the absorbent structure. An increase in the number of amine groups in absorbent structure, results in a higher capacity of upto 3.03 moles CO2/moles amine. Aromatic amines substituted with alkyl groups at the 2nd and 5th position show an increase in both absorption rate and capacity. © 2008 The Institution of Chemical Engineers
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