Search results for "Picture"
showing 10 items of 150 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.
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…
Using Audio-Logs for Analyzing the Development of a Common Operational Picture in Multi-agency Emergency Response
2020
Multi-agency emergency response requires effective communication and collaboration for building and maintaining a common operational picture. Full-scale exercises are shown to be effective for learning, and for training the collaborative skills needed. This paper presents a methodology for analysis of real-time communication for building the common operational picture, using audio-logs. The analysis of the audio-logs provides insights for both practitioners and researchers in the emergency management domain concerning the dynamics of inter-agency collaboration and information exchanges when responding to emergencies. Coding and categorizing of audio-log-based information exchanges among mul…
Jacqueline Woodson’s narrative style in The Other Side: An African American picture book for children
2012
The Other Side (2001) is a children’s story with multicultural characters and themes that can be regarded as an aesthetic exploration of the human experience in the process of the acquisition of knowledge. Following the Black Arts Movement, Jacqueline Woodson’s work portrays many of the issues that are present in the real world but seldom appear in children’s literature, such as racial division or interracial relationships. Using the metaphor of a fence, this African American author reveals issues of loneliness and friendship, inclusion and exclusion, and the overcoming of prejudice and segregation through the wisdom of Clover and Annie, an African American and a white girl, who become frie…
Dynamical Casimir-Polder force on a partially dressed atom near a conducting wall
2010
We study the time evolution of the Casimir-Polder force acting on a neutral atom in front of a perfectly conducting plate, when the system starts its unitary evolution from a partially dressed state. We solve the Heisenberg equations for both atomic and field quantum operators, exploiting a series expansion with respect to the electric charge and an iterative technique. After discussing the behaviour of the time-dependent force on an initially partially-dressed atom, we analyze a possible experimental scheme to prepare the partially dressed state and the observability of this new dynamical effect.