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I detta arbete undersöks huruvida ett konceptuellt fokus på fysikundervisningen, samt en förståelseinriktad examinationsform, påverkar elevers konceptuella förståelse av fysik. Detta är intressant av två anledningar: 1) Skolans styrdokument efterfrågar (bl.a.) konceptuella förståelsekunskaper, och 2) Traditionell fysikundervisning är dålig på att skapa en korrekt, konceptuell förståelse av fysik. Det här arbetet granskar resultaten från en icketraditionell undervisning, där flervalsfrågeverktyget FCI använt före och efter undervisning ger en bild av elevernas konceptuella förståelseutveckling. Den undervisning som undersöks i detta arbete visade sig vara drygt 100 % effektivare än motsvarande traditionella undervisning vad gällde att förbättra resultaten på diagnosverktyget FCI. Även om elevantalet var väldigt litet (endast tio elever) är resultatet så markant att det nog ändå äger viss giltighet. Arbetet undersöker även elevers föreställningar om fysik. Ett mindre påtagligt resultat i kombination med det lilla elevantalet gör det svårt att säga något om huruvida elevernas föreställningar om fysik blev mer fördelaktiga än vid traditionell undervisning. Resultaten pekar på det, men det är långtifrån säkerställt. Slutligen undersökte arbetet också varaktigheten hos de kunskaper eleverna erhöll. Det visade sig att de fyra elever som skrev FCI efter ett uppehåll i fysikundervisningen på tio månader presterade nästan lika bra som då de skrev provet direkt efter avslutad undervisning. De hade inte tappat mer än 10 % av sina poäng.

Finite structure splitting (FSS) is a bottleneck for quantum dot (QD) based solid state entangled photon pair generator (EPPG) for Quantum Key Distribution (QKD) application. In QD, entangle photon pairs are generated through a cascaded emission process—biexciton to exciton to ground state. The FSS of the excitonic state destroys the entanglement of the photon pairs, hence needs to be eliminated. FSS can be tuned by engineering the crystal growth direction, varying dot shape or size, changing the material composition and/or applying external strain. Numerical investigation of FSS and designing of realistically-sized QD based EPPG demands multiscale-multiphysics many-body simulation efforts. To this end, in this work, we report the coupling of full configuration integration (FCI) method with the atomistic empirical tight-binding (TB) models (10-band sp3s* and 20-band sp3d5s*) to calculate the excitonic energetics and FSS in recently reported multimillion-atom III-V dot-in-nanowire structures. The core of the computational framework comprises two parts: i) NEMO3D, which, using the TB models, can compute single-electron energetics of multimillion-atom structures, and ii) An FCI kernel, which computes the many-particle energetics and wavefunctions using the single-electron outputs as derived from NEMO3D. NEMO3D is a broad platform that handles geometry construction, calculation of strain distributions and built-in potential fields, solving the Schrodinger’s equation and computing optical matrix elements. Three output files from NEMO3D are of particular importance for the FCI toolkit: i) Single-electron energy values, ii) Eigen functions, and iii) Relaxed atom positions of the device. FCI calculates the Coulomb and Exchange matrix elements associated with multi-particles and forms the many-body Hamiltonian. The excitonic states (electron-hole pair) are calculated by solving the many-body Hamiltonian and the value of FSS, if exists, is determined. Recently, nitride-based nanostructured devices have been found to be a promising candidate for single and entangled multi-photon emitter applications. The principal goal of this dissertation is to facilitate the numerical design of InGaN/GaN based dot-in-nanowire EPPG units. To this end, a number of kernels in NEMO3D and FCI packages were augmented. The geometry constructor in NEMO3D was extended for two non-polar planes of wurtzite crystal: m-plane and a-plane. It is found that these two non-polar planes, with much smaller built-in piezoelectric fields, exhibit improved optical transition probabilities than the polar c-plane counterpart. As test cases, light-emitters in dot-in-wire and multiple quantum well (MQW) configurations were simulated and compared in all three (c-plane, m-plane, and a-plane) growth directions. TCAD toolkits are used to simulate the terminal optical characteristics such as internal quantum efficiency (IQE) and spontaneous emission rate. Hexagonal-base truncated-pyramid shaped QD was also added to the NEMO3D geometry constructor as pyramid shaped dots offer directionality and better extraction efficiency of emitted photons, which is important for single or entangled photon generators. The FCI simulator was modified for calculating the excitonic states that involve an electron-hole pair. As for EPPG design, four device structures are considered: i) Disk-in-nanowire on the polar c-plane, ii) pyramid shaped dot-in-nanowire on polar c-plane, iii) Disk-in-nanowire on non-polar m-plane, and iv) Disk-in-nanowire on non-polar a-plane. Simulations are done for different disk thicknesses, material compositions, quantum dot shapes and crystal directions. Results and in-depth analysis are presented on the effects of these design parameters on many-body energetics e.g. binding energy, excitonic bandgaps and FSS. The derivation of excitonic transition probability from single-electron momentum matrix is discussed in detail. Finally, an EPPG design is proposed employing the entangled polarization profiles from two excitonic emissions.

[pt] O objetivo deste estudo consiste em analisar o efeito das condições financeiras sobre a atividade econômica e entender o papel destas na transmissão da política monetária. Nossas evidências sugerem que, no caso dos Estados Unidos, um aperto nas condições financeiras possui efeito bastante similar a um choque contracionista de juros. Apesar disso, ao controlarmos a taxa de juros para o FCI, os resultados indicam que inovações de política monetária não atuam através das condições financeiras. Tal conclusão, no entanto, não pode ser generalizada para outros países. Encontramos que, no caso do Canadá, as condições financeiras possuem relevância na transmissão da política monetária, uma vez que o efeito de um choque de juro sobre a produção industrial e a inflação após o controle para as condições financeiras, é praticamente nulo. / [en] The aim of this study is to analyze the effect of financial conditions on economic activity and to understand their role in the transmission of monetary policy. Our evidence suggests that, in the case of the United States, a tightening of financial conditions has an effect very similar to a contractionary interest rate shock. Despite this, when controlling the interest rate for the FCI, the results indicate that monetary policy innovations does not operate through financial conditions. Such a conclusion, however, can t be generalized to other countries. We find that, in the case of Canada, financial conditions are relevant to the transmission of monetary policy, since the effect of an interest rate shock on industrial production and inflation after controlling for financial conditions, is practically nil.

This article focuses on the results of a research about teaching General Physics concepts to college students, and stresses the relevance of evaluating this kind of knowledge. Between 2009 and 2011, 4,535 students from the Pontifical Catholic University of Perú went through an evaluation process using the Force Concept Inventory test. The data results showed no significant improvement in the students’ learning process after having learned the concepts of force and motion, matters included in Physics 1 and Physics 2. The hardest concept to learn was Newton’s second law. Furthermore, a relevant amount of the students evaluated found no relation between learning these concepts and passing the courses. / Este artículo sintetiza el análisis de los resultados de un estudio acerca de la enseñanza de conceptos de Física en alumnos universitarios y la utilidad de evaluar este tipo de conocimientos. Entre los años 2009 y 2011, 4535 alumnos de la Universidad Católica han sido evaluados con la prueba Force Concept Inventory (FCI) a. Los resultados indican que los conocimientos de fuerza y movimiento se implantan entre los cursos de Física 1 y Física 2, y no se encuentra una mejora significativa después. El concepto con mayor dificultad de aprendizaje es la segunda ley de Newton. Además, existe un importante número de alumnos para los cuales no hay relación entre la ganancia de conceptos y la aprobación del curso.

Ce manuscrit est dédié au transport relativiste cinétique sous influence de champs magnétiques, identifié comme obstacle pour la modélisation et la simulation intégrée, dans le cadre de la Fusion par Confinement Inertiel (FCI). Une réalisation importante concerne le développement d'un code déterministe de référence, 2Dx-3Dv, de type Maxwell-Fokker-Planck-Landau, permettant la prise en compte de fonctions de distribution à large degré d'anisotropie. Ce travail se situe à l'interface de l'analyse numérique, des mathématiques appliquées, et de la physique des plasmas. Un deuxième résultat marquant concerne la dérivation d'un modèle collisionel multi-échelle, pour le transport d'électrons relativistes dans la matière dense. Des processus importants sont mis en évidence pour la FCI, et une analogie est menée vis-à-vis des processus de transport collisionels connus en radiothérapie. Enfin, un modèle mésoscopique aux moments angulaires, avec fermeture entropique, a été dérivé et utilisé pour le dépôt de dose pour la radiothérapie. Des schémas numériques précis, d'ordre élevé, et robustes, ont été développé dans ce cadre. / This manuscript is dedicated to the relativistic kinetic transport, under the influence of the magnetic field, identified as a barrier for the modeling and integrated simulations, in the frame of the Inertial Confinement Fusion (ICF). An important achievement concerns the development of a deterministic, reference code, 2Dx-3Dv, of Maxwell-Fokker-Planck-Landau type, that permits the treatment of distribution functions with large anisotropy degree. This work is at the interface between the numerical analysis, applied mathematics, and plasma physics. Another milestone result concerns the derivation of a multi-scale, collisional model, for the transport of relativistic electrons in dense matter. A set of processes is demonstrated to be of importance for ICF, and an analogy is conducted with respect to well-known collisional transport processes in radiotherapy. Finally, a mesoscopic angular moment model, with entropic closure, is derived and employed for radiotherapy dose computation. High order precise and robust numerical schemes are then developed in this framework.

Cette thèse se décompose en deux parties : i) l'étude du creusement d'un canal dans un plasma sous-dense (0.1nc

Les propriétés radiatives sont d'une importance cruciale lors de l'étude des plasmas astrophysiques et de fusion, particulièrement dans des conditions hors équilibre thermodynamique local (hors-ETL). C'est pourquoi nous avons développé un modèle collisionnel-radiatif, capable de calculer les propriétés radiatives en toutes conditions de température et de densité. Nous avons intégré à ce modèle de nouveaux facteurs de Gaunt développés par nous-mêmes. Ces facteurs permettent d'obtenir des sections efficaces des processus atomiques plus précis que les formules classiques et semi-empiriques, nécessaires au calcul des populations atomiques. Ils ont été obtenus en utilisant des méthodes sophistiquées, telles que les méthodes distorted-wave et generelized-line-strength, à l'aide du code FAC. Dans le but de valider nos résultats, nous les avons comparés dans un premier temps, aux calculs de Hill et Rose d'un plasma composé d'un mélange de carbone et de 5% de silicium, dans des conditions ETL et hors-ETL. Les résultats sont très satisfaisants, aussi bien à l'ETL qu'hors-ETL. Nous avons aussi comparé nos résultats à la transmission mesurée par Xiong et al. d'un plasma de silicium à Te = 72 eV et Ne = 1.3 x 10²¹ cm⁻³. Là encore, nous obtenons un bon accord. Cependant, on constate la présence de quelques écarts au niveau du décalage spectral de certaines raies, ainsi que l'absence de certaines transitions. Cette absence peut s'expliquer par certaines configurations électroniques manquantes dans le calcul de structure atomique. Nous nous sommes aussi intéressés à l'absorption d'un mélange de carbone et de 5% de germanium avec un nombre restreint de configurations électroniques. Nous avons exploré l'effet d'interaction de configurations ainsi que l'effet d'un champ radiatif. Nous avons également déduit des lois permettant de calculer rapidement les lois de Planck et de Rosseland. Ces lois concernent pour le moment le carbone, le silicium et le germanium, pour Te entre 250 et 350 eV et Ne entre 2 et 8 x 10²³ cm⁻³. / The radiative properties are of utmost importance when studying astrophysical and ICF plasmas, particularly in non local thermodynamic equilibrium conditions. This is the reason why we have developed a collisional-radiative model that enables us to calculate the radiative properties of plasmas under any temperature and density conditions. We developed and implemented new Gaunt factors to the CR model. These factors greatly improve the precision when calculating the cross sections of the microscopic processes. These cross sections are required to calculate the populations of the atomic levels. We obtained these new factors by using the distorted-wave and generalized line strength methods of the Flexible Atomic Code (FAC).In order to validate our new-developed CR model, we compared our results to those of Hill and Rose, of a plasma composed of carbon and 5% silicon, in LTE and NLTE conditions. We obtained satisfactory results in both conditions. We also compared our results to the experimental transmission measured by Xiong et al., of a pure silicon plasma, with Te = 72 eV et Ne = 1.3 x 10²¹ cm⁻³. Again, we obtained results that are in good agreement with the measured spectrum. However, we noticed some discrepancies in the line shift of some lines, and some missing transitions. This can be explained by the absence of certain electronic configurations in the calculation of the atomic structure with the Cowan atomic code.We also explored the absorption of a plasma composed of carbon and 5% germanium with a restricted number of electronic configurations. We investigated the effect of configuration interaction and the effect of the radiative field. We also developed new laws that predict the Planck and Rosseland mean opacities very quickly. For the time being, these laws work for carbon, silicon and germanium, with Te between 250 and 350 eV, and Ne between entre 2 et 8x10²³ cm⁻³.

I detta arbete undersöktes och jämfördes begreppskoherens och attityd till fysik blandelever på fysik- respektive naturvetenskapsprogrammet vid gymnasieskolanPolhemskolan i Lund. Begreppskoherensen undersöktes med Force Concept Inventorysom är ett omdiskuterat flervalstest från USA som ska mäta studentersbegreppskoherens för kraftbegreppet inom den klassiska mekaniken. Eftersom mångaundersökningar visar att intresset för fysik minskar undersöktes också elevernas attitydtill fysik med ett svenskt test av Likertmodell.Undersökningarna gjordes på elever som precis börjat åk 1 och på äldre elever som lästkursen Fysik A inom båda programmen. Resultatet av undersökningarna är att elevernapå fysikprogrammet har större begreppskoherens för kraftbegreppet än eleverna pånaturvetenskapsprogrammet och att begreppskoherensen höjs efter Fysik A. Attitydentill fysik är dessutom mer positiv på fysikprogrammet men eleverna pånaturvetenskapsprogrammet har större spridning i attityd. Slutsatsen är attPolhemskolans fysikprogram har lyckats locka de elever som det är tänkt för. / In this paper the conceptual coherence and towards physics among students in thephysics and science program at Polhemskolan in Lund were measured and compared.The conceptual coherence was measured with the Force Concept Inventory, a muchdebated multiple choice test from USA that is supposed to measure students’ conceptualcoherence for the concept of force in classical mechanics. Since many studies show thatthe interest in physics is declining the students’ attitude towards physics was alsomeasured with an attitude test of Likert model.The study is done among students that just started year one and older students that havehad instruction in physics at the Swedish correspondence to high school. The result ofthe study is that the students at the physics program have a higher conceptual coherencefor the concept of force than the students at the science program and that the coherence4is improved with the physics course Fysik A. The attitude towards physics is morepositive at the physics program but the attitudes among the students at the scienceprogram are more widely scattered. The conclusion is that the physics program atPolhemskolan has succeeded in attracting the students it is meant for.

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