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Rhetoric and the origins of the human sciences: A Foucauldian tale untold
Poisoning of Hydrogen Dissociation at Pd (100) by Adsorbed Sulfur Studied by ab initio Quantum Dynamics and ab initio Molecular Dynamics
We report calculations of the dissociative adsorption of H_2 at Pd (100)
covered with 1/4 monolayer of sulfur using quantum dynamics as well as
molecular dynamics and taking all six degrees of freedom of the two H atoms
fully into account. The ab initio potential-energy surface (PES) is found to be
very strongly corrugated. In particular we discuss the influence of tunneling,
zero-point vibrations, localization of the nuclei's wave function when narrow
valleys of the PES are passed, steering of the approaching H_2 molecules
towards low energy barrier configurations, and the time scales of the center of
mass motion and the other degrees of freedom. Several ``established'' concepts,
which were derived from low-dimensional dynamical studies, are shown to be not
valid.Comment: 4 pages, 3 figures, submitted to Surf. Sci. Lett. Other related
publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm
Spin and angular momentum in the nucleon
Using the covariant spectator theory (CST), we present the results of a
valence quark-diquark model calculation of the nucleon structure function f(x)
measured in unpolarized deep inelastic scattering (DIS), and the structure
functions g1(x) and g2(x) measured in DIS using polarized beams and targets.
Parameters of the wave functions are adjusted to fit all the data. The fit
fixes both the shape of the wave functions and the relative strength of each
component. Two solutions are found that fit f(x) and g1(x), but only one of
these gives a good description of g2(x). This fit requires the nucleon CST wave
functions contain a large D-wave component (about 35%) and a small P-wave
component (about 0.6%). The significance of these results is discussed.Comment: 27 pages; 13 figure
Quivers, curves, and the tropical vertex
Elements of the tropical vertex group are formal families of
symplectomorphisms of the 2-dimensional algebraic torus. Commutators in the
group are related to Euler characteristics of the moduli spaces of quiver
representations and the Gromov-Witten theory of toric surfaces. After a short
survey of the subject (based on lectures of Pandharipande at the 2009 Geometry
summer school in Lisbon), we prove new results about the rays and symmetries of
scattering diagrams of commutators (including previous conjectures by
Gross-Siebert and Kontsevich). Where possible, we present both the quiver and
Gromov-Witten perspectives.Comment: 43 page
Large-N limit of the generalized 2D Yang-Mills theory on cylinder
Using the collective field theory approach of large-N generalized
two-dimensional Yang-Mills theory on cylinder, it is shown that the classical
equation of motion of collective field is a generalized Hopf equation. Then,
using the Itzykson-Zuber integral at the large-N limit, it is found that the
classical Young tableau density, which satisfies the saddle-point equation and
determines the large-N limit of free energy, is the inverse of the solution of
this generalized Hopf equation, at a certain point.Comment: 11 pages, add a paragraph after eq.(20) and add one reference,
accepted for publication in: Nucl. Phys. B (2000
Explosive hypervelocity drag accelerator
Accelerator for launching hypervelocity projectile by drag force of jet produced by gaseous explosive product
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