In this thesis, two applications of dimensional deconstruction are studied. The first application is a model for neutrino oscillations in the presence of a large decon- structed extra dimension. In the second application, Kaluza{Klein dark matter from a latticized universal extra dimension is studied. The goal of these projects have been twofold. First, to see whether it is possible to reproduce the relevant features of the higher-dimensional continuum theory, and second, to examine the effect of the latticization in experiments. In addition, an introduction to the the- ory of dimensional deconstruction as well as to the theory of continuous extra dimensions is given. Furthermore, the various higher-dimensional models, such as Arkani-Hamed{Dvali{Dimopolous (ADD) models and models with universal extra dimensions, that have been intensively studied in recent years, are discussed. / QC 20101202

We consider a simple model for invisible neutrino decay as a sub-leading effect in the standard three-flavor neutrino oscillation framework, and use the Cayley–Hamilton formalism to obtain a full set of neutrino oscillation probabilities in matter. These are given as analytical series expansions in the small parameters α ∼ O(λ^2) and s_13 ∼ O(λ), where λ ≡ 0.2 is a “book-keeping parameter” denoting the order of the expansion. We produce explicit formulas for P_eµ, P_eτ , P_µµ, P_µτ , and P_ττ to order O(λ^3), and for P_ee to order O(λ^2), all having first corrections of order O(λ^4). Moreover, we also present vacuum limits of our expressions, as well as discuss the effect of decay on unitarity. We show that all rows in the unitarity table have corrections of order O(λ^2), with the second and third rows having additional corrections of order O(1). In the limit of no decay, unitarity is restored, and we furthermore recover known results for all probabilities. / Vi betraktar en enkel modell för osynligt neutrinosönderfall som en icke-ledande effekt inom det vedertagna ramverket för oscillationer med tre neutrinosmaker och använder Cayley–Hamilton-formalismen för att erhålla en fullständig uppsättning av sannolikheter för neutrinooscillationer i materia. Dessa ges som analytiska serieutvecklingar i de små parametrarna α ∼ O(λ^2) och s_13 ∼ O(λ), där λ ≡ 0.2 är en gemensam “bokföringsparameter” som anger serieutvecklingens ordning. Vi tar fram explicita uttryck för P_eµ, P_eτ , P_µµ, P_µτ och P_ττ till ordning O(λ^3) och för P_ee till ordning O(λ^2), med första korrigeringar för alla sannolikheterna till ordning O(λ^4). Därutöver presenterar vi gränsvärden för våra uttryck i vakuum samt diskuterar sönderfallets inverkan på unitaritet. Vi finner att alla rader i unitaritetstabellen har korrigeringar till ordning O(λ^2) och därtill korrigeringar till ordning O(1) för den andra och tredje raden. I avsaknad av sönderfall återfås unitaritet och vi reproducerar dessutom kända resultatför alla sannolikheter.

Abstract Iris The power of quantum computing lies in its ability to perform certain calculations and solve complex problems exponentially faster than classical computers. This potential has profound implications for a wide range of fields, including particle physics. This thesis lays a fundamental foundation for understanding quantum computing. Particular emphasis is placed on the intricate process of quantum gate decomposition, an elementary lynchpin that underpins the development of quantum algorithms and plays a crucial role in this research. In particular, this concerns the implementation of quantum algorithms designed to simulate the dynamic evolution of multi-particle quantum systems - so-called Hamiltonian simulations. The concept of quantum gate decomposition is introduced and linked to quantum circuit optimisation. The decomposition of quantum gates plays a crucial role in fault-tolerant quantum computing in the sense that an optimal implementation of a quantum gate is essential to efficiently perform a quantum simulation, especially for near-term quantum computers. Part of this thesis aims to propose a new explicit tensorial notation of quantum computing. Two notations are commonly used in the literature. The first is the Dirac notation and the other standard formalism is based on the so-called computational basis. The main disadvantage of the latter is the exponential growth of vector and matrix dimensions and the fact that it hides some relevant quantum properties of the operations by increasing the apparent number of independent variables. A third possible notation is introduced here, which describes qubit states as tensors and quantum gates as multilinear or quasi-multilinear maps. Some advantages for the detection of separable and entangled systems and for measurement techniques are also shown. Finally, this thesis demonstrates the advantage of quantum computing in the description of multi-particle quantum systems by proposing a quantum algorithm to simulate collective neutrino oscillations. Collective flavour oscillations of neutrinos due to forward neutrino-neutrino scattering provide an intriguing many-body system for time evolution simulations on a quantum computer. These phenomena are of particular interest in extreme astrophysical settings such as core-collapse supernovae, neutron star mergers and the early universe. A detailed description of the physical phenomena and environments in which collective flavor oscillations occur is first reported, and the derivation of the Hamiltonian governing the evolution of flavor oscillations is detailed. The aim is to reproduce this evolution using a quantum algorithm. To manage the computational complexity, we use the Trotter approximation of the time evolution operator, which mitigates the exponential growth of circuit complexity. The quantum algorithm was designed to work on a trapped-ion based testbed (the theory of which is presented in detail). After machine-aware optimisation, the quantum circuit implementing the algorithm was run on the real quantum machine 'Quantinuum', and the results are presented and discussed.

Neutrinooszillationen sind das einzige Phänomen jenseits des Standardmodells, das experimentell mit hoher statistischer Signifikanz bestätigt wurde. Diese Arbeit präsentiert eine Messung der atmosphärischen Neutrinooszillationen unter Verwendung von acht Jahren an Daten, die zwischen 2011 und 2019 vom IceCube DeepCore-Detektor aufgenommen wurden. Die Ereignisauswahl wurde im Vergleich zu früheren DeepCore-Messungen verbessert, wobei ein besonderes Augenmerk auf ihre Robustheit gegenüber systematischen Unsicherheiten in den Detektoreigenschaften gelegt wurde. Die Oszillationsparameter werden über eine Maximum-Likelihood-Fit an gebinnte Daten in der gemessenen Energie und Zenitwinkel geschätzt, wobei die Erwartungswerte aus gewichteten simulierten Ereignissen abgeleitet werdem. Diese Arbeit diskutiert den Simulations- und Datenauswahlprozess sowie die statistischen Methoden, die verwendet werden, um einen genauen Erwartungswert unter variablen Detektoreigenschaften und anderen systematischen Unsicherheiten zu liefern. Die Messung wird zunächst unter Verwendung des Standardmodells der Drei-Flavor-Oszillation durchgeführt, wobei das atmosphärische Massensplitting und der Mischwinkel auf $\Delta m^2_{32} = 2.42_{-0.75}^{+0.77} \times10^{-3};\mathrm{eV}^2$ und $\sin^2\theta_{23} = 0.507_{-0.053}^{+0.050}$ geschätzt werden. Das Drei-Flavor-Modell wird dann um einen zusätzlichen Masseneigenzustand erweitert, der einem sterilen Neutrino mit Massensplitting $\Delta m^2_{41} = 1;\mathrm{eV}^2$ entspricht und mit den aktiven $\nu_\mu$- und $\nu_\tau$-Flavorzuständen mischen kann. Es wird kein signifikantes Signal eines sterilen Neutrinos beobachtet, und die Mischungsamplituden zwischen den sterilen und aktiven Zuständen werden auf $|U_{\mu 4}|^2 < 0.0534$ und $|U_{\tau 4}|^2 < 0.0574$ bei 90\% C.L. begrenzt. Diese Grenzwerte sind um den Faktor zwei bis drei strenger als das vorherige DeepCore-Ergebnis, und die Einschränkung von $|U_{\tau 4}|^2$ ist die stärkste der Welt. / Neutrino oscillations are the only phenomenon beyond the Standard Model that has been confirmed experimentally to a very high statistical significance. This work presents a measurement of atmospheric neutrino oscillations using eight years of data taken by the IceCube DeepCore detector between 2011 and 2019. The event selection has been improved over that used in previous DeepCore measurements with a particular emphasis on its robustness with respect to systematic uncertainties in the detector properties. The oscillation parameters are estimated via a maximum likelihood fit to binned data in the observed energy and zenith angle, where the expectation is derived from weighted simulated events. This work discusses the simulation and data selection process, as well as the statistical methods employed to give an accurate expectation value under variable detector properties and other systematic uncertainties. The measurement is first performed first under the standard three-flavor oscillation model, where the atmospheric mass splitting and mixing angle are estimated to be $\Delta m^2_{32} = 2.42_{-0.75}^{+0.77} \times10^{-3}\;\mathrm{eV}^2$ and $\sin^2\theta_{23} = 0.507_{-0.053}^{+0.050}$, respectively. The three-flavor model is then extended by an additional mass eigenstate corresponding to a sterile neutrino with mass splitting $\Delta m^2_{41} = 1\;\mathrm{eV}^2$ that can mix with the active $\nu_\mu$ and $\nu_\tau$ flavor states. No significant signal of a sterile neutrino is observed and the mixing amplitudes between the sterile and active states are constrained to $|U_{\mu 4}|^2 < 0.0534$ and $|U_{\tau 4}|^2 < 0.0574$ at 90\% C.L. These limits are more stringent than the previous DeepCore result by a factor between two and three and the constraint on $|U_{\tau 4}|^2$ is the strongest in the world.

[pt] O princípio da equivalência é um pressuposto fundamental da Teoria da Relatividade Geral, entretanto, nas tentativas de quantização da gravidade os cálculos estão levando, muitas vezes, a pequenas violações desse princípio (VEP). Por esse motivo, se mostra necessário testá-lo e obter limites estatísticos para essas violações, a fim de possivelmente descartar alguns cenários. Uma das frentes com grande possibilidade de limitar os valores dessa violação é analisando a oscilação de neutrinos atmosféricos de altas energias, gerados pelos raios cósmicos. A oscilação padrão de sabores dos neutrinos que atravessam a Terra se torna desprezível em altas energias, enquanto a oscilação induzida por VEP se torna cada vez mais proeminente nessa faixa da energia. Neste trabalho, usamos uma abordagem minimalista da VEP, em que ela aconteceria através de diferentes valores de constantes gravitacionais para cada autoestado de massa de neutrino, parametrizado como Gi ≡ γiG onde o G é contante gravitacional, e traçamos limites para os parâmetros \Phi \Delta\gamma_21 e \Phi \Delta\gamma_21 no plano (\Phi \Delta\gamma_21 , \Phi \Delta\gamma_31), onde o \Phi é o potencial gravitacional. Para isso, foram usados os dados de rastros de múons gerados da interação de neutrinos atmosféricos com a rocha ou gelo, coletados por um ano pelo IceCube na sua forma completa (IC-86). Os múons possuem energias entre 400 GeV e 20 TeV, e os dados coletados foram comparados com os valores esperados pelos melhores modelos de produção de neutrinos muônicos atmosféricos. / [en] The equivalence principle is a fundamental assumption of General Relativity. However, in several quantum gravity scenarios, small violations of thisprinciple (VEP) is expected. For this reason, it is important to test this principle and obtain statistical limits on its violation, in order to possibly discardsome scenarios. One way to constrain this violation is analyzing the flavor oscillation pattern of high-energy atmospheric neutrinos, generated by cosmicrays. The standard oscillation of neutrino s flavor crossing the Earth becomesnegligible at high energies, while the oscillation induced by VEP becomes increasingly prominent in this range of energy. In this work, we use a minimalisticapproach about the VEP, in which it would occur because of different valuesof gravitational constants for each neutrino mass eigenstate, parameterized asGi ≡ γiG where G is the gravitational constant, and we derive limits on theparameters Phi Deltagamma_21 and Phi Deltagamma_21 in the (Phi Deltagamma_21 , Phi Deltagamma_31) plane, where Phi is thegravitational potential. To this end, muon-tracks events generated from theinteraction of atmospheric neutrinos with the rock or ice, collected for oneyear by IceCube in its complete form (IC-86), were used. The detected muonshave energies between 400 GeV and 20 TeV, and the collected data has beencompared with the values expected by the best models of atmospheric muonneutrino production.

Nesta tese, realizamos dois tipos de estudos fenomenológicos através de uma análise detalhada de alguns experimentos terrestres atuais e futuros. No primeiro, estudamos dois mecanismos exóticos de conversão de sabor: descoerência quântica e interações não padrão do neutrino com a matéria. Para descoerência, vinculamos o parâmetro de descoerência bem como testamos como distinguir a solução de descoerência pura do mecanismo padrão de oscilação no contexto de duas gerações. No caso das interações não padrão, assumimos que esta é subdominante frente ao mecanismo de oscilação padrão, e encontramos os possíveis limites que poderão ser obtidos para essas interações utilizando uma fábrica de neutrinos futura. No segundo tipo de estudo, determinamos os parâmetros de oscilação solares pela análise combinada dos dados dos neutrinos solares e de KamLAND, e estimamos a precisão nos parâmetros de mistura atmosféricos que poderá ser atingida pelos experimentos de LongBaseLine futuros MINOS, ICARUS e OPERA. Por fim, investigamos a possibilidade dos experimentos futuros do duplo decaimento sem neutrinos de determinar os parâmetros de não oscilação. / In this thesis, we have done two kind of phenomenological studies through a detailed analysis of present and future terrestrial experiments. In the first study, we analyze two exotic mechanisms of flavour conversion: quantum decoherence and non-standard neutrino-matter interactions. In the case of decoherence, we impose constraints on the decoherence parameter and test how to distinguish between the pure decoherence solution and the standard neutrino ascillation mechanism in the contexto f two neutrino generations. For non-standard interactions, assuming it as a sub-leading process compared to the standard oscillation, we find the possible limits that can be achieved on the strength of these interactions using a future neutrino factory. In the second part of the study, we determine the solar oscillation parameters using a combined analysis of solar neutrino and KamLAND data, and estimate the precision on the atmospheric mixing parameters by that can be accomplished by the LongBaseline experiments MINOS, ICARUS and OPERA. Finally, we investigate the capability of future neutrinoless Double beta decay experiments to determine the non-oscillation parameters.

This thesis is devoted to the theory and phenomenology of neutrino physics. While the standard model of particle physics has been extremely successful, it fails to account for massive neutrinos, which are necessary to describe the observations of neutrino oscillations made by several different experiments. Thus, neutrino physics is a possible window for exploring the physics beyond the standard model, making it both interesting and important for our fundamental understanding of Nature. Throughout this thesis, we will discuss different aspects of neutrino physics, ranging from taking all three types of neutrinos into account in neutrino oscillation experiments to exploring the possibilities of neutrino mass models to produce a viable source of the baryon asymmetry of the Universe. The emphasis of the thesis is on neutrino oscillations which, given their implication of neutrino masses, is a phenomenon where other results that are not describable in the standard model could be found, such as new interactions between neutrinos and fermions. / QC 20100630

No description available.

[pt] A oportunidade ímpar da construção do primeiro laboratório subterrâneo no Hemisfério Sul precisa ser alicerçada com importantes objetivos científicos, de maneira a competir com os demais laboratórios já existentes ao redor do planeta. Assim, no intuito de auxiliar na solidificação desta ideia, esta tese tem o propósito de verificar o potencial de um detector de neutrinos no futuro laboratório de ANDES para a observação de neutrinos vindos da próxima Supernova Galáctica. A observação de tais partículas é de fundamental importância para a compreensão do mecanismo de explosão de estrelas e para inferir ou desvendar propriedades dos neutrinos. Para tal, simulamos o número de eventos para o decaimento Beta inverso e para o espalhamento elástico v - p que seriam obtidos com a próxima supernova com o detector de ANDES considerando diferentes tipos de cintiladores líquidos, levando em conta o efeito MSW. Mostramos que através do espalhamento elástico v - p é possível reconstruir o fluxo total de todos os sabores de neutrinos, energia média e total liberados por neutrinos não-eletrônicos. Além disso, a comparação da razão dos números de eventos que vem de corrente carregada (depende da oscilação) e de corrente neutra (independente de oscilação), nos permite inferir a hierarquia de massa para alguns casos. Adicionalmente, estudamos a contribuição do laboratório de ANDES para a observação do efeito de matéria da Terra ao compararmos dados com outros detectores do Hemisfério Norte. Finalmente, investigamos a precisão angular para determinar a direção de uma supernova apenas usando o registro de neutrinos, que pode ser o caso de Supernovas que formam buracos negros ou sofram efeito de obscurecimento devido a poeira interestelar. / [en] The unique opportunity of construction of the first underground laboratory in the Southern Hemisphere must be grounded with important scientific goals in order to compete with others already existing laboratories around the word. In order to compete with idea as much as possible, this PhD Thesis aims to investigate the potential of a future neutrino detector at the ANDES laboratory to the observation of such particles is of fundamental importance to understanding the mechanism and starbust inferred or unravel properties of neutrinos as mass hierarchy, for example. To this end, we simulate the number of events for inverse beta decay and the elastic scattering of v - p that would be obtained with nearby supernova at the ANDES detector taking into account different types of liquid scintillator ande the phenomenon of MSW effect. We show that through the v - p elastic scattering is possible to reconstruct the total flux of all flavors of neutrinos, total and average energy released by non-electron neutrinos. furthermore, comparison of the ratio of observed and theoretical prediction, the number of the ANDES laboratory to the Northern Hemisphere. Finally, we investigate the angular precision for determining the direction of the supernova only using its neutrinos, which can be the situation when either supernovae collapses forming black holes or obscuration due to interstellar dust.

Orientador: Pedro Cunha de Holanda / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-16T08:47:51Z (GMT). No. of bitstreams: 1 MedinaJaime_Miguel_M.pdf: 2665434 bytes, checksum: ff126a38e30aec81b803a8fdcddcbc96 (MD5) Previous issue date: 2010 / Resumo: Neste trabalho apresentamos um estudo de alguns problemas que ainda não forem esclarecidos na física de neutrinos do modelo padrão (MP) e encaminhamos eles na direção de física nova. Para esse fim, estuda-se uma classe de extensões de Gauge quirais do MP com simetria SU(3)C x SU(3)L x U(1)X (modelos 331), onde estudamos a interação eletrofraca dos neutrinos com a matéria via correntes carregadas e neutras (CC e CN) através dos bósons Gauge do modelo para processos de espalhamento elástico coerente. Finalmente, encontramos vínculos entre as contribuições não padrão no modelo 331 com as interações não padrão (INP) em experimentos de seção de choque, onde encontramos que o modelo 331 apresenta INP diagonais universais da ordem e a M2 W,Z / M2 X <~ O(10-3). Mostramos que o valor esperado no vácuo (VEV) para o tão procurado bóson de Higgs neste modelo tem que ser ?2 <~174.105GeV e os VEV V > 1.3TeV e 142 GeV < ?1 < 201GeV. Os novos bósons do modelo deverão ter massas maiores a 610 GeV / Abstract: We present a study of some problems that are not yet clarified in Standard Model (SM) neutrino physics and guide them in the direction of new physics. To this aim, we study a class of extensions of the SM Gauge chiral symmetry SU(3)CSU(3)LU(1)X (331 model), where we study the electroweak interaction of neutrinos with matter via charged and neutral current (CC and NC) by the gauge bosons of the model for coherent elastic scattering process. We finally found connections between the non-standard contributions on 331 with non-standard interactions (NSI) in cross section experiments, where we find that the model 331 has diagonal universal NSI of order e a M2 W,Z / M2 X <~ O(10-3) . We show that the expected value in vacuum (VEV) for the quite searched Higgs boson in this model has to be ?2 <~174.105 GeV and the VEV V > 1.3TeV and 142 GeV < ?1 < 201 GeV. The new bosons of the model must have masses greater than 610 GeV / Mestrado / Física das Particulas Elementares e Campos / Mestre em Física