Search results for "PICT"
showing 10 items of 286 documents
The Three-Body Problem
1972
The quantum mechanical three-body problem has been studied with increasing interest in the last decade. The main progress was achieved by deriving integral equations which are not only theoretically correct, but also practically applicable. Such equations allow us in particular to investigate, besides three-body bound states, the scattering of an elementary particle from a bound two-particle system.
Levy flights and nonlocal quantum dynamics
2013
We develop a fully fledged theory of quantum dynamical patterns of behavior that are nonlocally induced. To this end we generalize the standard Laplacian-based framework of the Schr\"{o}dinger picture quantum evolution to that employing nonlocal (pseudodifferential) operators. Special attention is paid to the Salpeter (here, $m\geq 0$) quasirelativistic equation and the evolution of various wave packets, in particular to their radial expansion in 3D. Foldy's synthesis of "covariant particle equations" is extended to encompass free Maxwell theory, which however is devoid of any "particle" content. Links with the photon wave mechanics are explored.
SUPERFIELDS AND CANONICAL METHODS IN SUPERSPACE
1986
We consider the “supersymmetric roots” of the Heisenberg evolution equation as describing the dynamics of superfields in superspace. We investigate the superfield commutators and their equal time limits and exhibit their noncanonical character even for free superfields. For simplicity, we concentrate on the D=1 case, i.e., the superfield formulation of supersymmetric quantum mechanics in the Heisenberg picture and, as a soluble example, the supersymmetric oscillator. Finally, we express Noether’s theorem in superspace and give the definition of the global conserved supercharges.
Coarse grained and fine dynamics in trapped ion Raman schemes
2004
A novel result concerning Raman coupling schemes in the context of trapped ions is obtained. By means of an operator perturbative approach, it is shown that the complete time evolution of these systems (in the interaction picture) can be expressed, with a high degree of accuracy, as the product of two unitary evolutions. The first one describes the time evolution related to an effective coarse grained dynamics. The second is a suitable correction restoring the {\em fine} dynamics suppressed by the coarse graining performed to adiabatically eliminate the nonresonantly coupled atomic level.
Scaling laws in the distribution of galaxies
2004
Research done during the previous century established our Standard Cosmological Model. There are many details still to be filled in, but few would seriously doubt the basic premise. Past surveys have revealed that the large-scale distribution of galaxies in the Universe is far from random: it is highly structured over a vast range of scales. To describe cosmic structures, we need to build mathematically quantifiable descriptions of structure. Identifying where scaling laws apply and the nature of those scaling laws is an important part of understanding which physical mechanisms have been responsible for the organization of clusters, superclusters of galaxies and the voids between them. Find…
Master equation for cascade quantum channels: a collisional approach
2012
It has been recently shown that collisional models can be used to derive a general form for the master equations which describe the reduced time evolution of a composite multipartite quantum system, whose components "propagate" in an environmental medium which induces correlations among them via a cascade mechanism. Here we analyze the fundamental assumptions of this approach showing how some of them can be lifted when passing into a proper interaction picture representation.
Visual Imagery, Mental Models, and Reasoning
2006
Abstract: The focus of this paper is the relation between Steven Kosslyn’s visual mental images and Johnson-Laird’s mental models. Knauff et al. presented empirical evidence and a challenging argument for the hypothesis that in fact “visual imagery impedes reasoning.” I argue that these results may look embarrassing for pictorialists, but closer inspection suggests that they are actually harmless. I argue that the presented evidence fails to show that imagery impedes reasoning. I present some objections to the explanation proposed by Knauff and Johnson-Laird by pointing out some terminological and conceptual problems. Afterwards, I sketch an alternative explanation, which is more pictoriali…
Cuando un príncipe besa a una rana : ¡Sorpresa! Una propuesta didáctica desde la homosexualidad
2017
Resumen: En esta propuesta didactica, utilizamos el album ilustrado como herramienta para la ensenanza de contenido linguistico, asi como valores sociales y civicos a un grupo de estudiantes de ELE de nivel A2. Utilizamos el album ilustrado El dia de la rana roja que narra la historia de dos principes que se enamoran y adoptan a una nina huerfana. Estructuramos nuestra propuesta en cuatro fases (introduccion, comprension, consolidacion, resignificacion), de las cuales las dos ultimas son las dos que mas desarrollamos. Planteamos una entrevista a la rana del cuento, un teatro con marionetas, y el dibujo del mapa del reino como actividades de introduccion. En la fase de comprension se sugiere…
La sala Cervantes de la Biblioteca Nacional
2004
El presente artículo pretende una aproximación iconográfica a la obra plástica de Antonio Muñoz Degraín (1840-1924) inspirada tanto en las aventuras del Quijote como en las desventuras de su celebrado autor. Por tanto, formarán parte de este estudio todas las pinturas que el artista valenciano realizó, entre los años de 1916 y 1919, para ser colgadas en las paredes de la sala Cervantes de la Biblioteca Nacional, cuya inauguración se produjo el 6 de marzo de 1920. (A)
La tabla gótica de "Sant Salvador" de Manzanera, una obra inédita de Reixac
2002
Dentro de la densa producción pictórica producida por Joan Reixac, y que aún conservamos, es necesario añadir esta tabla central inédita del "retablo del senyor Sant Salvador" de la Iglesia Parroquial de Manzanera, en Aragón, encargada por este pueblo al maestro hacia 1464, para presidir su templo recién construido. De nuestra investigación de los archivos municipales, hemos documentado esta tabla desconocida hasta ahora y añadimos así otro retablo al grupo de los trabajos bien conocidos de este pintor.