Search results for "ASIM"

The Bohm-Aharonov effect: A seven-dimensional structural group

1996

We realize a nonfaithful representation of a seven-dimensional Lie algebra, the extension of which to its universal enveloping algebra contains most of the observables of the scattering Aharonov-Bohm effect, as essentially self-adjoint operators: the scattering Hamiltonian, the total and kinetic angular momenta, the positions and the kinetic momenta. By restriction, we obtain the model introduced in Lett. Math. Phys.1 (1976), 155–163.

El capitalismo, contra el planeta / 4

2007

Efectos de un programa de entrenamiento de fuerza unilateral o bilateral sobre el rendimiento en gestos de fuerza velocidad y la asimetría bilateral …

2015

La capacidad de manifestar fuerza se revela fundamental para el rendimiento en gran cantidad de modalidades deportivas. En el futbol la capacidad de acelerar, decelerar, saltar o cambiar de dirección es un elemento importante para el rendimiento en la acción de juego (Hoff y Helgerund, 2004; Stolen, Chamari, Castagna, Wisloff, 2005; Bangsbo, Mohr, Krustrup,2006). Estas acciones están sustentadas en la manifestación de altos niveles de fuerza y potencia por parte del miembro inferior. Al diseñar un programa de intervención para la mejora de la manifestación de fuerza, la manipulación adecuada de las distintas variables que componen el programa de entrenamiento se revela fundamental para cons…

Dynamical Casimir-Polder force between an excited atom and a conducting wall

2016

We consider the dynamical atom-surface Casimir-Polder force in the non-equilibrium configuration of an atom near a perfectly conducting wall, initially prepared in an excited state with the field in its vacuum state. We evaluate the time-dependent Casimir-Polder force on the atom, and find that it shows an oscillatory behavior from attractive to repulsive both in time and in space. We also investigate the asymptotic behavior in time of the dynamical force and of related local field quantities, showing that the static value of the force, as obtained by a time-independent approach, is recovered for times much larger than the timescale of the atomic self-dressing, but smaller than the atomic d…

Présentation générale des trois textes publiés

2016

National audience

Axionic and nonaxionic electrodynamics in plane and circular geometry

2023

Various aspects of axion electrodynamics in the presence of a homogeneous and isotropic dielectric medium are discussed. 1. We consider first the "antenna-like" property of a planar dielectric surface in axion electrodynamics, elaborating on the treatment given earlier on this topic by Millar {\it et al.} (2017). We calculate the electromagnetic energy transmission coefficient for a dielectric plate, and compare with the conventional expression in ordinary electrodynamics. 2. We consider the situation where the medium exterior to the plate, assumed elastic, is "bent back" and glued together, so that we obtain a circular dielectric string in which the waves can propagate clockwise or counter…

Dispersion Interaction between Two Hydrogen Atoms in a Static Electric Field

2019

We consider the dispersion interaction between two ground-state hydrogen atoms, interacting with the quantum electromagnetic field in the vacuum state, in the presence of an external static electric field, both in the nonretarded and in the retarded Casimir-Polder regime. We show that the presence of the external field strongly modifies the dispersion interaction between the atoms, changing its space dependence. Moreover, we find that, for specific geometrical configurations of the two atoms with respect to the external field and/or the relative orientation of the fields acting on the two atoms, it is possible to change the character of the dispersion force, turning it from attractive to re…

Vacuum local and global electromagnetic self-energies for a point-like and an extended field source

2013

We consider the electric and magnetic energy densities (or equivalently field fluctuations) in the space around a point-like field source in its ground state, after having subtracted the spatially uniform zero-point energy terms, and discuss the problem of their singular behavior at the source's position. We show that the assumption of a point-like source leads, for a simple Hamiltonian model of the interaction of the source with the electromagnetic radiation field, to a divergence of the renormalized electric and magnetic energy density at the position of the source. We analyze in detail the mathematical structure of such singularity in terms of a delta function and its derivatives. We als…

Spatial correlations of field observables in two half-spaces separated by a movable perfect mirror

2023

We consider a system of two cavities separated by a reflecting boundary of finite mass that is free to move, and bounded to its equilibrium position by a harmonic potential. This yields an effective mirror-field interaction, as well as an effective interaction between the field modes mediated by the movable boundary. Two massless scalar fields are defined in each cavity. We consider the second-order interacting ground state of the system, that contains virtual excitations of both mirror's degrees of freedom and of the scalar fields. We investigate the correlation functions between field observables in the two cavities, and find that the squared scalar fields in the two cavities, in the inte…

La asimilación de experiencias problemáticas a través de narraciones: un estudio de caso

2014

Title: The assimilation of problematic experiences through narratives: A case study. Abstract: In this study we aim to describe the assimilation process through our participant narratives, Monica, who had oncological problems and to explore the advantages of the use of narratives for assimilating these expe- riences. Monica wrote 31 narratives during 8 months about her experiences of hav- ing fibroadenomas and benign tumors. These narratives were analized by the assimilation model and the Assimilation of Problematic Experiences Scale or APES. The procedure to obtain the data ended with a sample of 373 passages that were analized with APES. Those passages were related to eight differ- ent to…