3,895 research outputs found
Solvability of the G_2 Integrable System
It is shown that the 3-body trigonometric G_2 integrable system is
exactly-solvable. If the configuration space is parametrized by certain
symmetric functions of the coordinates then, for arbitrary values of the
coupling constants, the Hamiltonian can be expressed as a quadratic polynomial
in the generators of some Lie algebra of differential operators in a
finite-dimensional representation. Four infinite families of eigenstates,
represented by polynomials, and the corresponding eigenvalues are described
explicitly.Comment: 18 pages, LaTeX, some minor typos correcte
Colorful Associahedra and Cyclohedra
Every n-edge colored n-regular graph G naturally gives rise to a simple
abstract n-polytope, the colorful polytope of G, whose 1-skeleton is isomorphic
to G. The paper describes colorful polytope versions of the associahedron and
cyclohedron. Like their classical counterparts, the colorful associahedron and
cyclohedron encode triangulations and flips, but now with the added feature
that the diagonals of the triangulations are colored and adjacency of
triangulations requires color preserving flips. The colorful associahedron and
cyclohedron are derived as colorful polytopes from the edge colored graph whose
vertices represent these triangulations and whose colors on edges represent the
colors of flipped diagonals.Comment: 21 pp, to appear in Journal Combinatorial Theory
Consumer Price Behavior in Mexico Under Inflation Targeting: A Microdata Approach *
La serie de Documentos de Investigación del Banco de México divulga resultados preliminares de trabajos de investigación económica realizados en el Banco de México con la finalidad de propiciar el intercambio y debate de ideas. El contenido de los Documentos de Investigación, así como las conclusiones que de ellos se derivan, son responsabilidad exclusiva de los autores y no reflejan necesariamente las del Banco de México. The Working Papers series of Banco de México disseminates preliminary results of economic research conducted at Banco de México in order to promote the exchange and debate of ideas. The views and conclusions presented in the Working Papers are exclusively the responsibility of the authors and do not necessarily reflect those of Banco de México. Documento de Investigació
El Centro Urbano Presidente Alemán: un caso de apropiación de vivienda colectiva de mediados del s.XX en la Ciudad de México
El trabajo que aquí se presenta pretende estudiar un caso de vivienda
colectiva analizando la arquitectura a partir de las prefiguraciones y refiguraciones a fin
de observar las concordancias y definir los significados que el habitante proporciona a
los espacios arquitectónicos, colectivos y privados. El caso que se pone a revisión es el
Centro Urbano Presidente Alemán, proyecto arquitectónico de 1,080 apartamentos
desarrollado por el Arq. Mario Pani y construido entre los años 1947 a 1949 en la
Ciudad de México
Pentaquark spectroscopy: exotic Theta baryons
We propose a collective stringlike model of pentaquarks with the geometry of
an equilateral tetrahedron in which the four quarks are located at the four
corners and the antiquark in its center. The nonplanar equilibrium
configuration is a consequence of the permutation symmetry of the four quarks.
In an application to the spectrum of exotic Theta baryons, we find that the
ground state pentaquark has angular momentum and parity J(p)=1/2(-) and a small
magnetic moment of 0.382 nuclear magnetons. The decay width is suppressed by
the spatial overlap with the decay products.Comment: 6 pages, 2 figures, invited talk at Nuclear Physics, Large and Small,
April 19-22, 2004, Hacienda Cocoyoc, Mexico, to be published in AIP
Conference Proceedings. Reference adde
Empirical distributions of galactic spin parameters from the SDSS
Using simple dimensional arguments for both spiral and elliptical galaxies,
we present formulas to derive an estimate of the halo spin parameter
for any real galaxy, in terms of common observational parameters. This allows a
rough estimate of , which we apply to a large volume limited sample of
galaxies taken from the SDSS data base. The large numbers involved (11,597)
allow the derivation of reliable distributions, as signal adds up
significantly in spite of the errors in the inferences for particular galaxies.
We find that if the observed distribution of is modeled with a
log-normal function, as often done for this distribution in dark matter halos
that appear in cosmological simulations, we obtain parameters and , interestingly consistent with
values derived from simulations. For spirals, we find a good correlation
between empirical values of and visually assigned Hubble types,
highlighting the potential of this physical parameter as an objective
classification tool.Comment: 8 pages, 6 figures, expanded final version, MNRAS (in press
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