Joaquin JIMENEZ

In order to understand the rise of runaway solutions in the radiation reaction problem a mechanical model is used. An alternative demonstration of Daboul’s theorem, through Hurwitz’s criterion, is given. The origin of runaway solutions in electrodynamics is discussed. They arise when the particle has a negative mechanical mass or when approximations are used in the equation of motion. In the 1-dimensional mechanical model an exact and linear equation of motion for the particle is obtained, the corresponding exact solution is again runaway when the mechanical mass is negative. The exact solution is not runaway when the mechanical mass is positive. However, the use of approximations leads to an equation of motion which has runaway solutions. It is exhibited that the use of approximations in the 3-dimensional mechanical model is completely necessary because the general equation of motion for the particle is non-linear. The analysis of this case proceeds in a very similar way to the one carried out in electrodynamics. This means that the number of dimensions also plays an important role in the analysis

This work presents an alternative approach to obtain the quantum field equations in curved spacetime, considering that sufficiently small particles follow stochastic trajectories around geodesic. Our proposal is based on a stochastic differential equation in which the noise term experienced by the quantum particles is a consequence of the stochastic background in spacetime. This fact allows the particles to describe erratic movements and locally the universe exhibits characteristics akin to a lake with gentle ripples rather than a flat unyielding surface. Building upon this foundational understanding, we investigate the influence of this background on quantum-scale particles without considering the metric to be stochastic, rather we let test particles move randomly around the geodesic of macroscopic particles. Their behavior aligns with solutions to the Klein-Gordon (KG) equation specific to this curved spacetime. As the KG equation, in its non-relativistic limit within a flat spacetime, reduces to the Schrödinger equation, consequently, we propose a compelling connection: the Schrödinger equation may emerge directly from a spacetime lacking local smoothness.

Resumen: El presente artículo tiene como propósito reflexionar en torno a las relaciones entre sujetos humanos y dispositivos tecnológicos desde dos instalaciones artísticas: Máquina Cóndor (2006-en curso) y Máquina de Coser (2009-en curso), del artista visual chileno Demian Schopf, a través de la perspectiva crítica de los nuevos materialismos. Por medio de un breve recorrido teórico que aborda los estudios de Walter Benjamin (1936, 1983), Jane Bennett (2010), Jusi Parikka (2012, 2021), Manuel de Landa (2021), entre otros, propongo que las obras de Schopf son constitutivas de una poética del ensamblaje, en la que los roces entre cuerpos orgánicos y dispositivos tecnológicos propicia la configuración de un complejo entramado humano-maquínico. Como metodología, examino dos procedimientos discursivos de las obras que asientan dicha configuración: la escritura y el diálogo, mecanismos poéticos posibilitados por la inteligencia artificial. Abstract: The purpose of this article is to reflect on the relationship between human subjects and technological devices through two artistic installations: Máquina Cóndor (2006-ongoing) and Máquina de Coser (2009-ongoing), by Chilean visual artist Demian Schopf, through the critical perspective of new materialisms. By means of a brief theoretical journey that addresses the studies of Walter Benjamin (1936, 1983), Jane Bennett (2010), Jusi Parikka (2012, 2021), Manuel de Landa (2021), among others, I propose that Schopf's works are constitutive of a poetics of assemblage, in which the frictions between organic bodies and technological devices propitiates the configuration of a complex human-machinic framework. As a methodology, I examine two discursive procedures of the works that establish this configuration: writing and dialogue, poetic mechanisms made possible by artificial intelligence.

Tras la pandemia de la COVID-19 se empezó a potenciar el proceso de virtualización de contenidos de aprendizaje, que ha dado lugar al desarrollo de materiales audiovisuales de apoyo a la docencia. Estos materiales son a menudo vídeos de duración variable diseñados para complementar las estrategias tradicionales de formación y facilitar la adquisición de algunos contenidos de la materia curricular. El presente trabajo presenta una experiencia colaborativa entre docentes para la introducción de materiales audiovisuales como recursos para la educación universitaria de asignaturas de matemáticas básicas en cinco Grados de distintas ingenierías de la Universidad de Cantabria.

An alternative approach to analyze the nonrelativistic quantum dynamics of a rigid and extended charged particle taking into account the radiation reaction is discussed with detail. Interpretation of the field operators as annihilation and creation ones, theory of perturbations and renormalization are not used. The analysis is carried out in the Heisenberg picture with the electromagnetic field expanded in a complete orthogonal basis set of functions which allows the electromagnetic field to satisfy arbitrary boundary conditions. The corresponding coefficients are the field operators which satisfy the usual commutation relations. A nonlinear equation of motion for the charged particle is obtained. A careful consideration of the quantum effects allows the derivation of a linear equation of motion which is free of both runaway solutions and preacceleration, even for a point charge. Also, the electromagnetic mass, which is defined as the coefficient of the acceleration operator, vanishes for a point particle. However, this does not mean that the results are free of ambiguities which are exhibited and discussed.

Tras la pandemia de la COVID-19 se empezó a potenciar el proceso de virtualización de contenidos de aprendizaje, que ha dado lugar al desarrollo de materiales audiovisuales de apoyo a la docencia. Estos materiales son a menudo vídeos de duración variable diseñados para complementar las estrategias tradicionales de formación y facilitar la adquisición de algunos contenidos de la materia curricular. El presente trabajo presenta una experiencia colaborativa entre docentes para la introducción de materiales audiovisuales como recursos para la educación universitaria de asignaturas de matemáticas básicas en cinco Grados de distintas ingenierías de la Universidad de Cantabria.