Purely Long-Range Coherent Interactions in Two-Dimensional Structured Baths

In this work we study the quantum dynamics emerging when quantum emitters exchange excitations with a two-dimensional bosonic bath with hexagonal symmetry. We show that a single quantum emitter spectrally tuned to the middle of the band relaxes following a logarithmic law in time due to the existence of a singular point with vanishing density of states, i.e., the Dirac point. Moreover, when several emitters are coupled to the bath at that frequency, long-range coherent interactions between them appear which decay inversely proportional to their distance without exponential attenuation. We analyze both the finite and infinite system situation using both perturbative and non-perturbative methods.Comment: 18 pages, 7 figures. Text restructured. Extended discussion on experimental consideration

The calculation of single-nucleon energies of nuclei by considering two-body effective interaction, n(k,rho), and a Hartree-Fock inspired scheme

The nucleon single-particle energies (SPEs) of the selected nuclei, that is, 16O, 40Ca, and 56Ni, are obtained by using the diagonal matrix elements of two-body effective interaction, which generated through the lowest order constrained variational (LOCV) calculations for the symmetric nuclear matter with the AV18 phenomenological nucleon-nucleon potential. The SPEs at the major levels of nuclei are calculated by employing a Hartree-Fock inspired scheme in the spherical harmonic oscillator basis. In the scheme, the correlation influences are taken into account by imposing the nucleon effective mass factor on the radial wave functions of the major levels. Replacing the density-dependent one-body momentum distribution functions of nucleons, n(k,rho), with the Heaviside functions, the role of n(k,rho) on the nucleon SPEs at the major levels of the selected closed shell nuclei, is investigated. The best fit of spin-orbit splitting is taken into account when correcting the major levels of the nuclei by using the parameterized Wood-Saxon potential and the AV18 density-dependent mean field potential which is constructed by the LOCV method. Considering the point-like protons in the spherical Coulomb potential well, the single-proton energies are corrected. The results show the importance of including n(k,rho), instead of the Heaviside functions, in the calculation of nucleon SPEs at the different levels, particularly the valence levels, of the closed shell nuclei.Comment: 17 pages, 4 table

Reescritura en pareja : una tarea de aprendizaje inicial de lo escrito

This paper presents a re-writing task to be carried out in pairs by 5 to 7-year old early readers and writers. The paper aims to (i) show the importance of the pedagogical decisions undertaken by a teacher who choose to implement tasks which allow her to observe learning processes that remain hidden under other circumstances; and (ii)underscore the advanced capacities that the learners may show in their conversations and in their shared product texts when they are given the opportunity to do so. The paper concludes with a set of implications for classroom practice.En aquest article es presenta una tasca de reescriptura de textos en parella de dos infants en els moments inicials del procés d'aprenentatge del llenguatge escrit (entre 5 i 7 anys). Els objectius d'aquest article són els següents: (i) mostrar la importància de la decisió pedagògica del docent sobre el tipus de tasca que permet observar els processos d'aprenentatge que romandrien ocults en altres situacions; i (ii) cridar l'atenció sobre les capacitats que els aprenents poden arribar a mostrar tant en les interaccions verbals entre ells com en la producció de textos reescrits compartits, quan se'ls dona l'oportunitat de fer-ho. Finalment, es discuteixen els beneficis que l'aplicació a l'aula d'aquesta mena de tasca pot tenir en l'alfabetització inicial.En este artículo se presenta una tarea de reescritura de textos en pareja de dos niños en los momentos iniciales del proceso de aprendizaje del lenguaje escrito (entre 5 y 7 años). Los objetivos de este artículo son los siguientes: (i) mostrar la importancia de las decisiones pedagógicas tomadas por el docentesobre un tipo de tarea que permite observar los procesos de aprendizaje que permanecerían ocultos en otras situaciones; y (ii) llamar la atención sobre las capacidadesque los aprendices pueden llegar a mostrar tanto en las interacciones verbales entre ellos como en la producción de textos reescritos compartidos, cuando se les da la oportunidad de hacerlo. Por último, se resumen los beneficios que la utilización de este tipo de tareas puede tener en la alfabetización inicial

A review of minimal supersymmetric electro-weak theory

In this review article we study the Minimal Supersymmetric Electro-Weak theory (of leptons). The Lagrangian is constructed step by step in great detail, both in the superfield and component field formalism --- both on and off shell. Furthermore the Lagrangian is written in the more familiar four component formalism. Electro weak symmetry breaking is discussed, and the physical chargino- and neutralino states are introduced and discussed

Externality of Defense Expenditure in the United States: A New Analytical Technique to Overcome Multicollinearity

This study estimates a three-sector Feder–Ram model using US annual data for 1965–2014 to confirm the externality of defense expenditure in the United States. Although the model is often used in the literature to scrutinize whether this effect exists, a flaw intrinsic to this model is the appearance of multicollinearity. In this study, I introduced novel techniques, namely: the standardization and estimation of a simple slope, to estimate the model. The results are as follows. First, I prove that the multicollinearity problem can be resolved by standardization. Second, externality, which is judged to conventionally exist, is not found. Third, increases in defense expenditure bring about positive but limited economic growth when the ratio of private to defense expenditure in the previous year ranges from 5.09 to 6.82%. By re-estimating the model, this study contributes to developing the Feder–Ram model within the related literature

Rewriting Interaction

Interactive visual computer animation is becoming an important tool for science education in grade school. Unfortunately, students and teachers cannot easily create their own animations, because programming these systems tends to be too hard for non-professional programmers. I present an approach that simplifies the description of complex interactions of objects by describing interactions with declarative, temporal constraints. A system that describes animation in terms of the actions of the objects and the interactions between the objects is being built on top of a grid-based, graphical programming environment. KEYWORDS: visual animation, science education, visual programming, rewrite rules, temporal constraints. INTRODUCTION Visual animation can be used to display dynamic processes and are an important tool in grade school science education. Animation is even more useful if it can be programmed by the end users, that is, by the students and their teachers. Unfortunately, the compl..

Interaction Nets and Term Rewriting Systems

Term rewriting systems provide a framework in which it is possible to specify and program in a traditional syntax (oriented equations). Interaction nets, on the other hand, provide a graphical syntax for the same purpose, but can be regarded as being closer to an implementation since the reduction process is local and asynchronous, and all the operations are made explicit, including discarding and copying of data. Our aim is to bridge the gap between the above formalisms by showing how to understand interaction nets in a term rewriting framework. This allows us to transfer results from one paradigm to the other, deriving syntactical properties of interaction nets from the (well-studied) properties of term rewriting systems; in particular concerning termination and modularity. Keywords: term rewriting, interaction nets, termination, modularity. 1 Introduction Term rewriting systems provide a general framework for specifying and reasoning about computation. They can be regarde..