Dark-bright discrete solitons: a numerical study of existence, stability and dynamics

the present work, we numerically explore the existence and stability properties of different types of configurations of dark-bright solitons, dark-bright soliton pairs and pairs of dark-bright and dark solitons in discrete settings, starting from the anti-continuum limit. We find that while single discrete dark-bright solitons have similar stability properties to discrete dark solitons, their pairs may only be stable if the bright components are in phase and are always unstable if the bright components are out of phase. Pairs of dark-bright solitons with dark ones have similar stability properties as individual dark or dark-bright ones. Lastly, we consider collisions between dark-bright solitons and between a dark-bright one and a dark one. Especially in the latter and in the regime where the underlying lattice structure matters, we find a wide range of potential dynamical outcomes depending on the initial soliton speed.MICINN project FIS2008-0484

Escape dynamics in the discrete repulsive φ4 model

We study deterministic escape dynamics of the discrete Klein-Gordon model with a repulsive quartic on-site potential. Using a combination of analytical techniques, based on differential and algebraic inequalities and selected numerical illustrations, we first derive conditions for collapse of an initially excited single-site unit, for both the Hamiltonian and the linearly damped versions of the system and showcase different potential fates of the single-site excitation, such as the possibility to be "pulled back" from outside the well or to "drive over" the barrier some of its neighbors. Next, we study the evolution of a uniform (small) segment of the chain and, in turn, consider the conditions that support its escape and collapse of the chain. Finally, our path from one to the few and finally to the many excited sites is completed by a modulational stability analysis and the exploration of its connection to the escape process for plane wave initial data. This reveals the existence of three distinct regimes, namely modulational stability, modulational instability without escape and, finally, modulational instability accompanied by escape. These are corroborated by direct numerical simulations. In each of the above cases, the variations of the relevant model parameters enable a consideration of the interplay of discreteness and nonlinearity within the observed phenomenology. © 2012 Elsevier B.V. All rights reserved

Methexis

Se trata de un proyecto que potencia la participación activa de alumnos, profesores y padres en la dinámica educativa del centro. El objetivo general es: integrar a los alumnos en la vida escolar. Se estructura en tres bloques: actividades de aula, complementarias y actividades medioambientales. Estas últimas están en su mayoría relacionadas con la metereología: medición diaria de datos metereológicos, tratamiento estadístico de esos datos y definición del clima del municipio. Para llevar a cabo estos ejercicios se instala en el patio del colegio una caseta meteorológica. Otra de las actividades que ha suscitado gran interés, ya que ha permitido a los alumnos participar en la vida del centro, ha sido la creación de una revista escolar. La valoración de la experiencia es muy positiva por lo que se pretende su continuidad en años posteriores.Madrid (Comunidad Autónoma). Consejería de Educación y CulturaMadridMadrid (Comunidad Autónoma). Subdirección General de Formación del Profesorado. CRIF Las Acacias; General Ricardos 179 - 28025 Madrid; Tel. + 34915250893ES