Möjligheten till att introducera kvantmekanik från ett kvantinformationsperspektiv, för gymnasieelever utan tidigare erfarenhet av kvantmekanik, undersöks i denna studie. Kvantmekaniska koncept såsom den statistiska tolkningen av en vågfunktion, kollapsen av en vågfunktion vid en mätning, operatorer, sammanflätning och interferens introduceras med hjälp av kvantdatorkoncepten: kvantbitar, kvantgrindar, kvantparallellism och Deutschalgoritmen. En Workshop upplagda efter den elevaktiva metoden Peer Instruction hölls på fyra skolor i Uppsala för totalt 77 elever. Peer Instruction går ut på att lektionen delas in i segment som täcker ett koncept åt gången. Varje segment består av en kort genomgång följt av en konceptuell fråga som först besvaras enskilt, sen får deltagarna diskutera frågan och till sist besvaras samma fråga igen. Vilka typer av konceptuella frågor som kan skapa intressanta diskussioner kring kvantmekaniska koncept med hjälp av kvantdatorer undersöks. Hur olika nivåer av förkunskap om- och intresse för fysik, kvantfysik, kvantdatorer och programmering påverkar diskussionerna samt hur elevernas intresse för ämnet och synen på dess svårighetsgrad utvecklas med workshopen undersöks också. Workshopen var över lag uppskattad av eleverna - utifrån kommentarerna på frågorna som ställdes efteråt. Andelen korrekta svar på frågorna efter diskussionerna var höga och workshopen ökade intresset för fysik, kvantfysik och framförallt kvantdatorer samtidigt som synen på svårigheten av desamma minskade. / The possibility to introduce quantum mechanics, to Swedish pre-university and pre-quantum mechanical students, from a quantum information perspective is examined in this study. Quantum mechanical concepts such as the statistical interpretation of a wave function, the collapse of a wave function when a measurement takes place, operators, entanglements and interference are introduced using the quantum computer concepts: qubuits, qubit gates, quantum parallelism and the Deutsch’s algorithm. A workshop organized according to Peer Instruction was held at 4 different schools in Uppsala, Sweden with a total of 77 participants. The lecture was divided into a number of short presentations each followed by a concept test, the concept test was first answered individually, followed by a disussion amongst the students and finally they answered the same question again. Different kinds of conceptual tests and how different levels of pre-knowledge and preinterest in physics, quantum mechanics, programming and quantum computers influenced the discussions were analysed. How the students attitude to the subject and how their view of how difficult it was changed, were also examined. The workshop was generally appreciated by the students - based on the comments in the questions that were asked after the workshop. The proportion of correct answers to the questions after the discussions was high. The workshop increased the interest in physics, quantum mechanincs and especially quantum computers, while reducing the view of the difficulty of the same.

Radiotherapy aims to strike a tumour with high accuracy, but anatomic changes and internal organ motion introduce uncertainties and therefore large margins are conventionally used to compensate for this. The MR-Linac will enable target tracking prior to and during treatment which will make daily adjustments of a treatment plan possible. But a motion tracking of the target requires fast 3D imaging and image processing which are currently not viable with sufficiently low latency. In this project a method to estimate the motion of a target by using a parameterized motion model created prior to treatment and a stream of 2D images acquired during treatment was studied. The motion model had been parameterized by using principal component analysis (PCA). The 2D images were aligned to the corresponding images in the motion model through deformable image registration which resulted in a deformation field. Then new parameters (eigenmode weights) of the motion model were calculated by taking the projection of the deformation field on a vector space spanned by the eigenmodes of the PCA motion model. An estimation of the motion was then created by applying the new weights to the PCA motion model. The results were evaluated by visual comparison and with quantitative metrics such as the Dice similarity coefficient. The method was applied to data from 9 volunteers and the results confirmed that the proposed method can estimate the motion of a target and indicated that it is most suitable for volunteers with large intra-fraction motion. The results also showed that the temporal resolution of the motion model can be increased by using 2D images of lower spatial resolution. The created motion model can be used for many clinical applications like retrospectively calculating the accumulated doses in the tumour and the organs-at-risk and potentially could be used for real-time target tracking.

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<p>In this thesis, we present results from detailed gas phase studies of intrinsic properties of fullerenes (C₆₀) and clusters of fullerenes as probed by slow multiply charged (atomic or cluster) ions in combination with coincidence time-of-flight mass spectrometry. We have investigated the structures, stabilities, and the electron mobilities of multiply charged clusters of fullerenes, (C₆₀)_n^r+ (r=2-5). We found that the (C₆₀)_n^r+ cluster ions are weakly bound by van der Waals forces and the electric conductivity is high in strong contrast to the typical characteristics of other van der Waals type clusters and fullerene crystals (fullerite), where the charge is strongly localized. The high charge mobility was rationalized within the framework of a novel classical static over-the-barrier model for two conducting spheres used to describe multiple charge transfer processes between two neighboring fullerenes in the cluster. The model results showed that electron transfer is possible as soon as the C₆₀-C₆₀ system is charged, consistent with earlier experimental results from slow C₆₀^q+ + C₆₀ collisions where an electric contact is established (during the very short interaction time of the collision) between the two molecules at distances outside the binding distance in the C₆₀-C₆₀ system. The present electrostatic model was also used to guide the interpretation of the measured kinetic energy releases in the fragmentation of multiply charged dimers, (C₆₀)₂^r+ → C₆₀^r1+ + C₆₀^r2+. </p><p>In like manner, we have measured kinetic energy releases in the break-ups of multiply charged monomer fullerene ions with the aid of fragment-ion momentum spectroscopy. This yielded an excellent platform for investigations of the projectile and target dependencies on various intrinsic features such as the ultimate Coulomb stability limits for C₆₀^r+ and C₇₀^r+ ions, competition between different reaction pathways, and multi-fragmentation processes. The experimental results for the stability limits for multiply charged fullerenes are discussed in view of recent high level Density Functional Theory calculations of C₆₀^r+ → C₅₈^(r-1)+ + C₂⁺ transition states and our electrostatic model. </p><p>The Density Functional Theory results are also used to check the validity and limitations of the classical model regarding the description of fragmentation processes, while a comparison with advanced molecular dynamic calculations of Ar⁸⁺+Na₄₀ collisions were made for investigating its applicability for charge transfer processes. We found that the present model indeed is useful for describing main features in inherent complex molecular processes at sufficiently low collision velocities. In addition, we propose an extension of the present model to consider two dielectric spheres immersed in a dielectric medium, which might be applied also outside the cluster research field.</p>

<p>This thesis adresses electric and magnetic noise and dissipation in magnetoelectronic nanostructures. Charge and spin current fluctuations are studied in various nanosized metallic structures consisting of both ferromagnetic and non-magnetic elements. The interplay between current and magnetization fluctuations, and the relation of these fluctuations to the electric and magnetic dissipation of energy, are considered. Special focus is on the enhancement of magnetization damping due to so-called spin pumping, which is shown to be directly connected to thermal spin current fluctuations.</p><p>Two fundamental sources of current noise are considered: Thermal noise and shot noise. Since a spin current polarized transverse to the magnetization is absorbed in a ferromagnet, transverse spin current fluctuations exert a fluctuating torque on the magnetization. This spin-transfer torque causes significant magnetization fluctuations in nanoscale ferromagnets. In single-domain ferromagnets in contact with normal electric conductors, the spin-current induced magnetization noise is directly connected to the magnetization damping caused by spin pumping. In non-uniformly magnetized ferromagnets, the spin-current induced magnetization noise is related to a nonlocal tensor damping that reflects the spatial variation of the magnetization. At low temperatures, spin current shot noise in the presence of an applied bias is the dominant contribution to the magnetization noise.</p><p>In spin valves, two ferromagnets are separated by a thin normal metal spacer. The interaction of the ferromagnets affects their magnetization noise and damping, which are shown to vary with the relative magnetic orientation of the ferromagnets. Due to giant magnetoresistance, the magnetization fluctuations cause resistance noise. The resistance noise is identified as a prominent source of electric noise at relatively high current densities. The noise level can vary substantially with the relative magnetic orientation.</p>

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<p><p>Misconceptions in physics and especially mechanics have been the object of several studiessince the first half of the 20th century. These studies have determined which misconceptions are present. A few or none studies have been made on how the education counters these misconceptions. It is therefore important to investigate the differences in knowledge between pupils in the ages of 13 and 16 years.</p><p>This study aims to investigate the knowledge of the concept of force amongst pupils in the age of 13 and 16 years, moreover to investigate if misconceptions are common with these pupils. The method selected for investigation was a survey with multiple choice questions and a few questions were the pupils were asked to draw arrows in pictures to represent forces. The result is shown in diagrams and interprets that they have a low level of understanding in this subject, it also shows that misconceptions are dominant. The difference in the results between the pupils aged 13 and 16 is not significant, and therefore the conclusion can be made that the education is performed in a wrong fashion.</p><p>Moreover, the results interpret that the pupils in the ninth year of compulsory education do not meet the objectives of the Swedish curriculum, where the pupils should have knowledge about pressure, energy and the build-up of matter where force plays an important part.</p></p> / <p><p>Vardagsföreställningar inom fysik och i synnerhet mekanik har sedan 1900-talet första hälft</p><p>hamnat i fokus i flera studier. Dessa studier har kartlagt vilka vardagsföreställningar som är</p><p>förekommande. Få eller inga undersökningar har genomförts där man ställer undervisningen</p><p>i fokus och hur den motverkar dessa vardagsföreställningar. Det är därför angeläget att</p><p>undersöka hur skillnader ser ut mellan år sju och år nio på grundskolan.</p><p>Det här arbetets syfte är att undersöka skillnaderna i förståelse för begreppet kraft mellan</p><p>grundskoleelever i år sju och nio, dessutom undersöka om vardagsföreställningar är vanliga</p><p>hos dessa elever.</p><p>Datainsamlingsmetoden för undersökningen var en enkät med flervalsfrågor samt ett fåtal</p><p>frågor där eleverna ombads rita kraftpilar i figurer.</p><p>Resultaten är sammanställda och pressenteras i diagram och visar att eleverna har en låg</p><p>kunskap och flera föreställningar är framträdande. Många har uppfattningen att krafter alltid</p><p>verkar på kroppar som är i rörelse.</p><p>Skillnaden i resultaten mellan år sju och år nio är inte betydande och slutsatsen kan därför</p><p>dras att undervisningen sker på ett felaktigt sätt.</p><p>Dessutom tyder resultaten på att måluppfyllelsen inte är tillräcklig för ett godkänt betyg</p><p>för stora delar av eleverna i år nio, eftersom eleven enligt uppnåendemålen ska ha kunskap om tryck, energi och materiens uppbyggnad, där kraft spelar en väsentlig roll.</p></p><p> </p>

<p>In this master thesis I have looked on two different kinds of representations of the Lie algebras <em>su</em>(2) and <em>sl</em>(2), and the tensor products of the representations.</p><p>In the first case I looked at a tensor product involving a representation similar to one that appears in an article by A. van Tonder. This representation and tensor product was investigated mainly to get a good comprehension in the subject and to understand some of the problems that can arise.</p><p>In the other case, which is the main problem in this thesis, I looked at a tensor product and representations that appears in an article by M. R. Gaberdiel. Here we deal with a tensor product of representations of <em>su</em>(2) with a specific value for the level at k = -4/3 and a specific eigenvalue of the Casimir operator at -2/9. This was done in the frame of finite dimensional Lie algebra and affine Lie algebra and not in the case of fusion rules as in the article by M. R. Gaberdiel.</p><p>In both cases some of the calculations where done from <em>in situ</em> and the investigation of the representations behaviour due to the step operators, theirs eigenvalue and theirs weight system.</p><p>Results and conclusions of the investigations are discussed in the last part of this thesis.</p><p> </p>

<p>In this master thesis I have investigated one-dimensional nanostructures, so called quantum wires. The goal was to grow them in situ on a stepped silicon surface and thereafter do several kinds of measurements, like Scanning Tunneling Microscopy, Low-Energy Electron Diffraction and Photoemission. The surface that was used was a Si(332) surface and the metals used in the growth of the quantum wires were gold and silver.</p><p>After the preparation and measurement of the stepped surface, evaporation of silver and gold was performed. The Scanning Tunneling Spectroscopy measurments were done on both Ag/Si(332) and Au/Si(332) surfaces. This gave information about the local density of stats on the surfaces and possible bandgaps.</p><p>All experiments were performed in ultra high vacuum, except the sample cutting and the first cleaning of the surface, which was done after the Shiraki method.</p>