Дисертації з теми "Berry phases"
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Pedder, Christopher James. "Berry phases in supersymmetric quantum mechanics." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611287.
Повний текст джерелаMoore, David Jeffrey. "Non-adiabatic Berry phases for periodic Hamiltonians." Thesis, University of Canterbury. Physics, 1991. http://hdl.handle.net/10092/8072.
Повний текст джерелаManini, Nicola. "Electron-Vibron Coupling in Charged Fullerene, Berry Phases and Superconductivity." Doctoral thesis, SISSA, 1996. http://hdl.handle.net/20.500.11767/3874.
Повний текст джерелаLouvet, Thibaud. "Phases relativistes en matière condensée." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEN025/document.
Повний текст джерелаThis thesis adresses the study of crystals called relativistic semi-metals, in which electrons behave like massless relativistic particles.The first historical example of such a material is graphene.In this planar arrangement of carbon atoms, electronic valence and conduction bands touch at two distincts points in the reciprocal lattice. Thus, graphene is a zero-gap semiconductor, a semi-metal.The dynamics of electrons close to the Fermi level is relativistic, described by a Dirac equation, although their velocity is a hunder times lower than the velocity of light in vacuum. Analogous semi-metallic phases have recently been identified: 3D Weyl and Dirac semimetals, as well as more exotic phases described by crossings with more than two bands. This variety of relativistic materials raises the question of their common properties. A first part of this thesis presents work related to the study of the stability of these phases, i.e. of the electronic band crossing. We have investigated this stability first by relating it to topological properties, then by evaluating the effect of disorder, such as the presence of impurities in the material. In the second part, we focus on the manifestation of the relativistic nature of these electrons in transport. In a first study, we examine the condition of existence of a finite conductivity exactly at the band crossing, due to the contribution of evanescent states. A second study concerns the anomalous transport under a magnetic field in Weyl semi-metals, as a manifestation of the chiral anomaly, a unique property of massless relativistic fermions
Bamler, Robert Verfasser], Achim [Gutachter] Rosch, and Alexander [Gutachter] [Altland. "Phase-Space Berry Phases in Chiral Magnets: Skyrmion Charge, Hall Effect, and Dynamics of Magnetic Skyrmions / Robert Bamler. Gutachter: Achim Rosch ; Alexander Altland." Köln : Universitäts- und Stadtbibliothek Köln, 2016. http://d-nb.info/1113178728/34.
Повний текст джерелаTrappe, Martin-Isbjörn [Verfasser], and Thomas [Akademischer Betreuer] Gasenzer. "Parity-Violating and Parity-Conserving Berry Phases for Hydrogen and Helium in an Atom Interferometer / Martin-Isbjörn Trappe ; Betreuer: Thomas Gasenzer." Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1177147998/34.
Повний текст джерелаDauphin, Alexandre. "Cold atom quantum simulation of topological phases of matter." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209076.
Повний текст джерелаIl existe cependant des phases qui échappent à la description de Landau. Il s'agit des phases quantiques topologiques. Celles-ci constituent un nouveau paradigme et sont caractérisées par un ordre global défini par un invariant topologique. Ce dernier classe les objets ou systèmes de la manière suivante: deux objets appartiennent à la même classe topologique s'il est possible de déformer continument le premier objet en le second. Cette propriété globale rend le système robuste contre des perturbations locales telles que le désordre.
Les atomes froids constituent une plateforme idéale pour simuler les phases quantiques topologiques. Depuis l'invention du laser, les progrès en physique atomique et moléculaire ont permis un contrôle de la dynamique et des états internes des atomes. La réalisation de gaz quantiques,tels que les condensats de Bose-Einstein et les gaz dégénérés de Fermi, ainsi que la réalisation de réseaux optiques à l'aide de faisceaux lasers, permettent d'étudier ces nouvelles phases de la matière et de simuler aussi la physique du solide cristallin.
Dans cette thèse, nous nous concentrons sur l'etude d'isolants topologiques avec des atomes froids. Ces derniers sont isolants de volume mais possèdent des états de surface qui sont conducteurs, protégés par un invariant topologique. Nous traitons trois sujets principaux. Le premier sujet concerne la génération dynamique d'un isolant topologique de Mott. Ici, les interactions engendrent l'isolant topologique et ce, sans champ de jauge de fond. Le second sujet concerne la détection des isolants topologiques dans les expériences d'atomes froids. Nous proposons deux méthodes complémentaires pour caractériser celles-ci. Finalement, le troisième sujet aborde des thèmes au-delà de la définition standard d'isolant topologique. Nous avons d'une part proposé un algorithme efficace pour calculer la conductivité de Berry, la contribution topologique à la conductivité transverse lorsque l'énergie de Fermi se trouve dans une bande d'énergie. D'autre part, nous avons utilisé des méthodes pour caractériser les propriétés quantiques topologiques de systèmes non-périodiques.
L'étude des isolants topologiques dans les expériences d'atomes froids est un sujet de recherche récent et en pleine expansion. Dans ce contexte, cette thèse apporte plusieurs contributions théoriques pour la simulation de systèmes quantiques sur réseau avec des atomes froids.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Viennot, David. "Géométrie et adiabaticité des systèmes photodynamiques quantiques." Phd thesis, Université de Franche-Comté, 2005. http://tel.archives-ouvertes.fr/tel-00011145.
Повний текст джерелаTaillefumier, Mathieu. "Quelques mécanismes non conventionnels de l'effet Hall anormal." Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00012052.
Повний текст джерелаpremières parties sont axées sur l'étude de quelques mécanismes
intrinsèques de l'effet Hall anormal. Nous montrons notamment que la
diffusion des porteurs de charge par des impuretés ou des défauts
donne une contribution intrinsèque non négligeable à l'effet Hall
anormal. Nous proposons ensuite une expérience, basée sur un réseau de
nanocylindres magnétiques, placé au dessus d'un gaz d'électrons
bidimensionnel, dans laquelle les contributions intrinsèques de
l'effet Hall anormal sont clairement identifiables et contrôlables.
Enfin, nous abordons le problème du mécanisme de chiralité de spin
proposé pour expliquer l'effet Hall dans le composé pyrochlore
Nd$_2$Mo$_2$O$_7$. En utilisant un modèle de gaz sur réseau ainsi
qu'une configuration magnétique non colinéaire (chirale), nous
montrons que la conductivité transverse a une dépendance complexe par
rapport à la chiralité de spin.
La dernière partie de ce manuscrit est dédiée à l'étude de quelques
propriétés des gaz d'électrons soumis à un champ magnétique
inhomogène. Après un bref rappel sur la dynamique d'électron en
présence d'un gradient de champ magnétique constant, nous abordons le
problème d'un champ magnétique périodique spatialement. En calculant
quelques états de Bloch aux points de haute symétrie, nous montrons qu'il
existe des états pour lesquels les électrons sont localisés au
voisinage des lignes de champ nul. Le calcul des courants de
probabilité montre que ces états sont porteurs de courants permanents
dont l'origine est liée aux inhomogénéités du champ magnétique au
voisinages des lignes de champ nul.
Gouverneur, Yves. "Phase de Berry et quantification de skyrmions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0002/MQ33663.pdf.
Повний текст джерелаMaamache, Mustapha. "Phase de berry, angle de annay et etats coherents action angle." Nice, 1993. http://www.theses.fr/1993NICE4625.
Повний текст джерелаDe, gail Raphaël. "Aspects topologiques des dérivés du graphène." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-00987051.
Повний текст джерелаSundaram, Ganesh. "Wave-packet dynamics in slowly perturbed crystals : gradient corrections and Berry-phase effects /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
Повний текст джерелаCeresoli, Davide. "Berry phase calculations of the rotational and pseudorotational g-factor in molecules and solids." Doctoral thesis, SISSA, 2002. http://hdl.handle.net/20.500.11767/4017.
Повний текст джерелаGomes, Sadoque Salatiel da Silva. "Quantização, estados coerentes e fases geométricas de um circuito RLC generalizado e explicitamente dependente do tempo." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/5766.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
We present an alternative quantum treatment for a generalized mesoscopic RLC circuit with time-dependent resistance, inductance and capacitance. Taking advantage of the Lewis and Riesenfeld and quadratic invariants we obtain exact nonstationary Schrödinger states for this electromagnetic oscillation system. Afterwards, we construct coherent states for the quantized RLC circuit and employ them to investigate some of the system s quantum properties, such as quantum fluctuations of the charge and the magnetic flux and the corresponding uncertainty product. In addition, we derive the geometric, dynamical and Berry phases for this nonstationary mesoscopic circuit. Finally we evaluate the dynamical and Berry phases for three special circuits. Surprisingly, we find identical expressions for the dynamical phase and the same formulae for the Berry s phase.
Apresentamos um tratamento quântico alternativo para um circuito RLC mesoscópico generalizado com resistência, indutância e capacitância dependentes do tempo. Usando o método de invariantes quânticos de Lewis e Riesenfeld e invariantes quadráticos, obtemos os estados de Scrhödinger não-estacionários para este circuito com oscilação eletromagnética. Em seguida, construímos os estados coerentes para o circuito RLC quantizado e os empregamos para investigar algumas das propriedades quânticas do sistema, tais como flutuações quânticas da carga, do fluxo magnético e o produto incerteza correspondente. Além disso, obtemos as fases geométricas, dinâmicas e de Berry para este circuito mesoscópico não estacionário. Finalmente, calculamos as fases dinâmica e de Berry para três casos particulares. Surpreendentemente, encontramos expressões idênticas para a fase dinâmica, e as mesmas expressões para a fase da Berry.
Lopes, Mirleide Dantas. "Teorema do índice em superfícies curvas de grafeno e fases de Berry." Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/5781.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The graphene consists of a two-dimensional hexagonal structure formed only by carbon atoms. It is a peculiar molecule, because in low energy its Hamiltonian can be described by the Dirac operator and this gives it some unusual characteristics. In this work the index theorem will be applied to graphene. This allows to estimates the number of zero modes of geometric variants of graphene by means of topological features of these molecules. Finally, it is observed that the index of the Hamiltonian of this system can be described in terms of Berry phases. And so, it is investigated the possibility of doing holonomic quantum computation using the topology of such molecules.
O grafeno consiste em uma estrutura bidimensional hexagonal constituída apenas por átomos de carbono. Trata-se de uma molécula bastante peculiar, pois em baixas energias o seu hamiltoniano pode ser descrito pelo operador de Dirac e isso lhe confere características incomuns. Neste trabalho o teorema do índice será aplicado ao grafeno. Teorema que permite estimar o número de modos zero das variantes geométricas do grafeno por meio das características topológicas destas moléculas. Por fim, observa-se que o índice do hamiltoniano deste sistema pode ser descrito em termos das fases de Berry. E dessa forma, investiga-se a possibilidade de fazer computação quântica holonômica, a partir da topologia de tais moléculas.
Yu, Hao. "Liquid Crystal Flat Optical Elements Enabled by Molecular Photopatterning with Plasmonic Metamasks." Kent State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=kent1595196794159313.
Повний текст джерелаBoutat, Driss. "Feuilletages isodrastiques et phase de Berry-Weinstein pour le mouvement des sous-variétés lagrangiennes : cas des surfaces symplectiques." Lyon 1, 1993. http://www.theses.fr/1993LYO10147.
Повний текст джерелаAugenstein, Peter Frederic [Verfasser], and Maarten [Akademischer Betreuer] DeKieviet. "Experimentelle Untersuchung geometrischer Berry-Phasen in metastabilem Helium mit einem Atomstrahl-Spinecho-Interferometer / Peter Frederic Augenstein ; Betreuer: Maarten DeKieviet." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180616960/34.
Повний текст джерелаAugenstein, Peter [Verfasser], and Maarten [Akademischer Betreuer] DeKieviet. "Experimentelle Untersuchung geometrischer Berry-Phasen in metastabilem Helium mit einem Atomstrahl-Spinecho-Interferometer / Peter Frederic Augenstein ; Betreuer: Maarten DeKieviet." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:16-heidok-217838.
Повний текст джерелаGunhan, Ali Can. "Environmental Effects On Quantum Geometric Phase And Quantum Entanglement." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609450/index.pdf.
Повний текст джерелаits stability decreases as the magnetic field strength increases. (By decrease in stability what we mean is the increase in the time rate of change of GP.) We showed that this decrease can be very rapid, and so it could be impossible to make use of it as a quantum logic gate in quantum information theory (QIT). To see if these behaviors differ in different environments, we analyze the same system for a fixed temperature environment which is under the influence of an electromagnetic field in a squeezed state. We find that the general dependence of GP on magnetic field does not change, but this time the effects are smoother. Namely, increase in magnetic field decreases the stability of GP also for in this environment
but this decrease is slower in comparison with the former case, and furthermore it occurs gradually. As a second problem we examine the entanglement of two atoms, which can be used as a two-qubit system in QIT. The entanglement is induced by an external quantum system. Both two-level atoms are coupled to a third two-level system by dipole-dipole interaction. The two atoms are assumed to be in ordinary vacuum and the third system is taken as influenced by a certain environment. We examined different types of environments. We show that the steady-state bipartite entanglement can be achieved in case the environment is a strongly fluctuating, that is a squeezed-vacuum, while it is not possible for a thermalized environment.
Wang, Mengfei Wang. "Photo-alignment of orientationally patterned surface for disclination generation and optical applications." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent153273906099599.
Повний текст джерелаCarvalho, Neto Osvaldo Fernandes. "Fases Geométricas e suas relações com a Teoria de Fibrados e Representação de Grupos." Universidade Federal da Paraíba, 2008. http://tede.biblioteca.ufpb.br:8080/handle/tede/7394.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
We present the own mathematic formalism to, first of all, study the holonomy interpretations of the adiabatic geometric phase presented by Berry-Simon and Aharanov-Anadan and, after this, the similirities found with the theory of representation groups, particularly, with the Borel-Weil-Bott theorem. These relations are made through classification of complex bundle line, and these results are used to introduce a cranked Hamiltonian. In general, we also show that the parameter space is a flag manifold or a submanifold of her and present a topologic argument of this space that indicates the relation between the structure Riemannian and the Berry s connection.
Apresentamos o formalismo matemático próprio para, primeiramente, estudarmos as interpretações holonômicas da fase geométrica adiabática apresentadas por Berry-Simon e Aharanov-Anadan e, em seguida, as similaridades encontradas com a Teoria de Representações de Grupos, em particular, com o teorema de Borel-Weil-Bott. Estas relações são feitas via classificação de fibrados linha complexos, e esses resultados são usados para introduzir um procedimento que trata a não-adiabaticidade e a adiabaticidade da fase de Berry por meio de uma modificação na hamiltoniana. Mostramos, também, que em geral, o espaço de parâmetros é uma variedade de bandeira ou uma subvariedade dela e apresentamos um argumento topológico desse espaço, que indica a relação entre a estrutura Riemanniana e a conexão de Berry.
Al-Saidi, Wissam Abdo. "Topics in the Theory of Small Josephson Junctions and Layered Superconductors." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1052148427.
Повний текст джерелаSawant, Rajath Ravindra. "Métasurface à gradient de phase diélectrique pour les applications d'optique classique et quantique." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4096.
Повний текст джерелаIn recent years, various optical functionalities have been demonstrated using metasurfaces which have attracted tremendous attention. Metasurfaces being diffractive optical components, show greater flexibility, including compactness, lightweight, arbitrary wavefront addressing capabilities exceeding those of refractive optical components. However, in terms of efficiency refractive components perform better and further optimization is required for metasurfaces in this direction. Considering this, here we design hybrid optical devices to combine the advantages of both the components. First, it is demonstrated how the dispersion of a simple optical element such as a prism can be mitigated using a metasurface. By employing phase gradient metasurfaces, the outgoing wavevectors can be controlled and hence the diffractive dispersion of metasurface. Utilizing this property, metasurfaces with relatively small phase gradients are designed and prism dispersion mitigation is experimentally demonstrated. Extending the same principle to lenses, metasurface to correct for lens chromatic aberration is designed in the wavelength range of 550-800nm. Also, it is shown that monochromatic aberration such as spherical aberration can also be corrected by designing an appropriate phase gradient for the metasurface. Analytical calculations, large area metasurface fabrication and comprehensive experimental characterization are done to demonstrate aberration correction of commercially available lenses. These developments are promising for future compact imaging systems. Realizing the potential of metasurfaces in classical optics, they are also used for Quantum optics applications. However, only a few works have been done in this direction. Hong Ou Mandel experiment, which is one of the basic experiments of Quantum optics, demonstrates quantum interference. Here, we propose to modify the original setup by replacing the beam splitter with a phase gradient metasurface. A novel metasurface is designed for this purpose called ‘Dual Gradient Metasurface’ which imparts additional functionality along with the beam splitter functionality. The nanofabrication of the metasurface is optimized to realize 50/50 transmission in the two diffracted orders to imitate a beam splitter. The superior control that metasurfaces offer over the phase, polarization and amplitude of light can be quite beneficial for manipulating the quantum states of light. This opens doors for harnessing the potential of metasurface for quantum technologies
Oliveira, Neto Vivaldo Lopes. "Structural properties of nanoscopic ring systems and their optical response." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/8131.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
In this thesis, the electronic and structural properties of nanostructured systems were studied aiming to get a realistic model for quantum rings, potentially adaptable for quantum dots. To attain these goals, several studies supported by experimental results were carried out that allowed the introduction to the building blocks for the theoretical models such as: the envelope function approach within the k.p approximation in quantum wells, and quantum ring/dot with perpendicular magnetic field and without spin-orbit interaction. In these models, the effects of size, strain and localization were subsequently introduced to understand the ring formation process and their effects in the photoluminescence and magneto-photoluminescence. The experimental results of atomic force microscopy indicated the importance of structural properties and the types of asymmetries possibly found in quantum rings after the growth process. The understanding of these effects and the evidence of the anisotropy in a preferential direction of the ring helped building more realistic models for the potential profiles. Various systems were then studied with success. They also included a controllably magnetic field (both in magnitude and orientation), beside the geometric deformation, making the ring ellipsoidal, and taking into account the spin-orbit interaction. The most realistic model was used to analyze the Berry phase generation and the relative weight of the contribution of each term of the Hamiltonian.
Nesta tese de doutorado, as propriedades eletrônicas e estruturais de sistemas nano estruturados foram estudadas visando a obtenção de um modelo realístico para anéis quânticos potencialmente adaptáveis a pontos quânticos. Para alcançar este objetivo, foram feitos alguns estudos, apoiados por resultados experimentais, que permitiram a construção passo a passo do modelo teórico, como: aproximação da função envelope na representação k.p em poços quânticos e anéis/pontos quânticos com campo magnético perpendicular e sem interação spin-órbita. Nestes modelos, os efeitos do tamanho, tensão e localização foram introduzidos subsequentemente para entender o processo de formação do anel e os resultados apresentados na fotoluminescência e na magneto-luminescência. O resultado experimental da microscopia de força atômica nos levou a analisar a importância das propriedades estruturais e os tipos possíveis de assimetria encontrados em anéis quânticos devido ao processo de crescimento. O entendimento desses efeitos e a evidência de anisotropia em uma direção preferencial do anel ajudou na construção de modelos mais realísticos para os perfis de potencial. Deste modo, vários sistemas foram estudados com sucesso. Eles também possuíam um campo magnético controlável (ambas, magnitude e orientação), além da deformação geométrica, que torna o anel elipsoidal, e a interação spin-órbita. O modelo mais realístico foi usado para analisar a geração da fase de Berry e o peso da contribuição de cada termo do Hamiltoniano.
Garcia, Gabriel Queiroz. "Fases geométricas para quasipartículas em grafeno na presença de deslocações." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/9556.
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Recently, Mesaros, Sadri and Zaanen investigated the rise of Berry phases in the dynamics of quasiparticle in graphene with edge dislocation. In opposition with disclinations, dislocations require only finites energies to be created so that is virtually impossible to prepare one crystal, which doesn't have dislocations. Mesaros, Sadri e Zaanen used the theory of classic elasticity, to introduce informations due deslocations, in the Hamiltonian of particle and also used tigth-binding method to describe the system. They obtained that dynamics particle acquires one Berry phase and which this phase can be used at applications in quantic computation. In this work, we use the Katanev and Volovich geometric theory of defects to introduce dislocations in the graphene's sheet. We obtain the metric which descibe edge dislocations. We obtain the Hamiltonian which descibe the dynamic of quasiparticle in the graphene at curved space-time with torsion. Write the Dirac equation to this system and investigate the rise of Berry phase in this system. We show that Berry phase obtained to our system depends of intensity of Burgers vector.
Recentemente, Mesaros, Sadri e Zaanen investigaram o aparecimento de fases de Berry na dinamica de quasiparticulas em grafeno com deslocagoes tipo edge. Em contraste com desclinagoes, as deslocagoes requerem apenas energias finitas para serem criadas, de modo que é virtualmente impossivel preparar um cristal que nao contem deslocagoes. Mesaros, Sadri e Zaanen usaram a teoria da elasticidade classica, para introduzir as informagoes devido a deslocacao, no hamiltoniano da particula e usaram metodo tight-binding numa aproximagao de continuo para descrever o sistema. Eles obtiveram que a dinamica da particula adquire uma fase de Berry e que esta fase pode ser usadas para aplicagoes em computagao quantica. Neste trabalho, usamos a teoria geometrica de defeitos de Katanaev e Volovich para introduzir deslocagoes em uma folha de grafeno em uma aproximagao de continuo. Obtemos a metrica que descreve uma deslocagao tipo edge. Obtemos o hamiltoniano que descreve a dinamica das quasiparticulas no grafeno neste espago curvo com torgao. Escrevemos a equagao de Dirac para esse sistemas e investigamos o aparecimento de fases de Berry neste sistema. Mostramos que a fase geometrica obtida para o nosso sistema depende da intensidade do vetor de Burgers.
Runyon, Matthew. "Experimental Design and Implementation of Two Dimensional Transformations of Light in Waveguides and Polarization." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36881.
Повний текст джерелаPavlovic, Goran. "Exciton-polaritons in low dimensional structures." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2010. http://tel.archives-ouvertes.fr/tel-00632151.
Повний текст джерелаJamali, Afsoon Jamali. "LARGE AREA TUNABLE LIQUID CRYSTAL LENS." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1541671894328594.
Повний текст джерелаDelplace, Pierre. "Etats de bord et cônes de Dirac dans des cristaux bidimensionnels." Paris 11, 2010. http://www.theses.fr/2010PA112354.
Повний текст джерелаThis thesis in physics constitutes a theoretical study of the edge states in bi-dimensional crystals which exhibit two Dirac cones (spin degenerated) in their dispersion relation. The two systems considered are graphene and the square lattice with half a magnetic quantum flux per plaquette. The analytical description of the dispersive energy levels in a high magnetic field (quantum Hall effect regime) due to the presence of edges is highlighted. According to the geometry of the crystal lattice and the shape of the edge, different kinds of coupling are induced between the components of the wave function. This gives rise to various structures of edge sates which however can be described in a common way. Without any magnetic field, some edge states can also exist in these systems, but they have a different origin and their existence itself depends on the shape of the edge. In the case of graphene, we show how to connect the existence of these edge states with a particular type of Berry phase, the so-called Zak phase. This approach allows, for instance, to understand how to manipulate these edge states by tuning the bulk parameters, what involves a topological transition of the Zak phase. Another type of topological transition has also been studied. It consists in the merging of the Dirac cones in the square lattice with half a quantum flux. We show that the mechanism leading to such a phenomena strongly differs from the one known in graphene, and that the physics around the transition can however be described within the same effective Hamiltonian. A shorter second part deals with the weak localization on a disordered cylinder with electronic interactions. The aim of this study is to illustrate the role of the geometry in the decoherence mechanisms due to electron-electron interactions in diffusive systems. The harmonics of the weak localization correction calculated reveal different regimes which probe the different length scales characterizing the decoherence. These lengths underline the sensibility of coherent processes to the geometry and are characterized by specified power laws in temperature
Cheneau, Marc. "Transition BKT et potentiels géométriques dans le gaz de Bose bidimensionnel." Paris 6, 2009. https://tel.archives-ouvertes.fr/tel-00556002.
Повний текст джерелаGlazar, Nikolaus. "Micropatterned Photoalignment for Wavefront Controlled Switchable Optical Devices." Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1460650961.
Повний текст джерелаQuddusi, Hajrah. "Role of internal degrees of freedom in the quantum tunneling of the magnetization in single-molecule magnets." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5442.
Повний текст джерелаPh.D.
Doctorate
Physics
Sciences
Physics
Yousefzadeh, Comrun. "TUNABLE LIQUID CRYSTAL BEAM STEERING DEVICE BASED ON PANCHARATNAM PHASE IN FRINGE FIELD SWITCHING MODE." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1627049349857564.
Повний текст джерелаGonzalez, Gabriel. "ELECTRON TRANSPORT IN SINGLE MOLECULE MAGNET TRANSISTORS AND OPTICAL LAMBDA TRANSITIONS IN THE NITROGEN-VACANCY CENTER IN DIAMON." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2976.
Повний текст джерелаPh.D.
Department of Physics
Sciences
Physics PhD
Abdalla, Leonardo Batoni. "Propriedades eletrônicas dos isolantes topológicos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-17072015-140214/.
Повний текст джерелаIn the search of a better understanding of the electronic and magnetic properties of topological insulators we are faced with one of its most striking features, the existence of metallic surface states with helical spin texture which are protected from non-magnetic impurities. On the surface these spin channels allows a huge potential for applications in spintronic devices. There is much to do and treating calculations via \\textit{Ab initio} simulations allows us a predictive character that corroborates the elucidation of physical phenomena through experimental analysis. In this work we analyze the electronic properties of topological insulators such as: (Bi, Sb)$_2$(Te, Se)$_3$, Germanene and functionalized Germanene. Calculations based on DFT show the importance of the separation from interlayers of Van der Waals in materials like Bi$_2$Se$_3$ and Bi$_2$Te$_3$. We show that due to stacking faults, small oscillations in the QLs axis (\\textit{Quintuple Layers}) can generate a decoupling of the Dirac cones and create metal states in the bulk phase Bi$_2$Te$_3$. Regarding the Bi$_2$Se$_3$ a systematic study of the effects of transition metal impurities was performed. We observed that there is a degeneracy lift of the Dirac cone if there is any magnetization on any axis. If the magnetization remains in plane, we observe a small shift to another reciprocal lattice point. However, if the magnetization is pointing out of the plane a lifting in energy occurs at the very $ \\Gamma $ point, but in a more intense way. It is important to emphasize that in addition to mapping the sites with their magnetic orientations of lower energy we saw that the lifting in energy is directly related to the local geometry of the impurity. This provides distinct STM images for each possible site, allowing an experimental to locate each situation in the laboratory. We also studied the topological transition in the alloy (Bi$_x$Sb$_{1-x}$)$_ 2$Se$_3$, where we identify a trivial and topological insulator for $x = 0$ and $x = 1$. Despite the obvious existence of such a transition, important details remain unclear. We conclude that doping with non-magnetic impurities provides a good technique for handling and cone engineering this family of materials so that depending on the range of doping we can eliminate conductivity channels coming from the bulk. Finally we studied a Germanene and functionalized Germanene with halogens. Using an asymmetrical functionalization and with the topological invariant $Z_2$ we noted that the Ge-I-H system is a topological insulator that could be applied in the development of spin-based devices.
Schaeffer, David. "La pompe à paire de Cooper : un read-out pour le Qubit Josephson." Phd thesis, Université Joseph Fourier (Grenoble), 2005. http://tel.archives-ouvertes.fr/tel-00011227.
Повний текст джерелаse comporter comme un système à deux niveaux. Les énergies des états quantiques macroscopiques sont
contrôlées par deux tensions de grille et par une tension de polarisation VB.
Le transfert d'une paire de Cooper à travers le circuit dissipe dans l'environnement électromagnétique
une quantité d'énergie 2eVB, correspondant à la polarisation en tension. Les propriétés de transport
à travers ce dispositif, en absence de quasiparticules résiduelles, font apparaître la compétition entre le
couplage des états dégénérés de la double île et le taux de relaxation en fonction de la tension de
polarisation. Tant que la relaxation est le facteur limitant, le courant est uniquement déterminé par la
relaxation, conduisant au régime quantique. Par contre, si le couplage devient le facteur limitant (ou
si la relaxation domine), la dynamique change et le courant paradoxalement diminue, menant au
régime Zéno. Aux tensions suffisamment basses, le supercourant est identifié à travers les trois jonctions
en série.
Dans ce travail, il s'agit aussi de comprendre l'effet d'un cycle d'évolution adiabatique, réalisé par
l'application des deux tensions de grille alternatives de même fréquence et d'amplitude en quadrature de
phase, produisant un courant de pompage à travers le circuit. Cette thèse présente dans quelle mesure
le pompage adiabatique peut être exploité pour "lire" l'état du système. Le courant de pompage est, en
effet, sensible à l'occupation de l'état quantique, la charge pompée dans l'état fondamental et dans le
premier état excité étant de signe opposé.
Radmanesh, Seyed Mohammad Ali. "Ultra-low Temperature Properties of Correlated Materials." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2511.
Повний текст джерелаLabeguerie, Pierre. "Modélisation du champ électrique interne d'un solide:application à la détermination des propriétés dérivées de la polarisation. Calcul du spectre de phonon." Phd thesis, Université de Pau et des Pays de l'Adour, 2005. http://tel.archives-ouvertes.fr/tel-00264922.
Повний текст джерелаWoollacott, Claire. "Electronic and plasmonic properties of real and artificial Dirac materials." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18227.
Повний текст джерелаMazzoni, Michele. "A fibre bundle approach to U(1) symmetries in physics." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16776/.
Повний текст джерелаCheneau, Marc. "Transition superfluide et potentiels géométriques dans le gaz de Bose bidimensionnel." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://tel.archives-ouvertes.fr/tel-00556002.
Повний текст джерелаGregefalk, Anton. "Adiabatic Shortcut to Geometric Quantum Computation in Noiseless Subsystems." Thesis, Uppsala universitet, Materialteori, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448903.
Повний текст джерелаKvantdatorer kan teoretiskt utföra vissa uppgifter som klassiska datorer vid realistiska tider inte kan. Att köra en kvantdator kräver exakt kontroll över systemet, till exempel genom adiabatisk utvecking, och isolering från omgiviningen för att behålla koherens. Denna rapport kombinerar dessa två, något motsägelsefulla, tekniker för felhantering. För att minska körtiden används en övergångsfri kvantkörningsalgoritm, också kallad adiabatisk genväg. Konceptet brusfria delsystem, en generalisering av dekoherensfria underrum, används för robusthet mot sammanflätning med omgivningen genom att skapa logiska kvantbitar som fungerar som en brusfri kod. Vidare tillämpas den adiabatiska genvägen för den brusfria koden på ett spinn-eko för att eliminera den dynamiska fasen, som är känslig för felpropagering, så att endast Berrys fas, som är okänslig för felpropagering, effektivt plockas upp. Motsvarande Hamiltonian härleds uttryckligen för de enda två fallen av tvådimensionella brusfria delsystem: 3 eller 4 kvantbitar med respektive totalspinn j = 1/2 och 0. Detta möjliggör beräkning med en geometrisk kvantdator baserad på en universell en-kvantbitsgrind, som också härleds explicit.
Delplace, Pierre. "ÉTATS DE BORD ET CÔNES DE DIRAC DANS DES CRISTAUX BIDIMENSIONNELS." Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00607781.
Повний текст джерелаDe, Chiara Gabriele. "Quantum information, entanglement and critical phenomena." Doctoral thesis, Scuola Normale Superiore, 2006. http://hdl.handle.net/11384/85888.
Повний текст джерелаLi, Shilong. "Probing and modeling of optical resonances in rolled-up structures." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-159996.
Повний текст джерелаNgome, Abiaga Juste Jean-Paul. "(Super) symétries des modèles semi-classiques en physique théorique et de la matière condensée." Phd thesis, Tours, 2011. http://tel.archives-ouvertes.fr/tel-00622874.
Повний текст джерела"Berry curvature in nonlinear systems." 2014. http://repository.lib.cuhk.edu.hk/en/item/cuhk-1291542.
Повний текст джерела在本論文,我們利用半古典動力學的博戈留波夫激發研究非線性系統的貝里曲率在相邊界上出現的臨界現象。結果顯示,當參數空間中的臨界曲面被越過,環繞橢圓不動點的博戈留波夫激發的非線性幾何相位發生非解析行為。
Kam, Chon Fai = 非線性系統的貝里曲率 / 甘駿暉.
Thesis M.Phil. Chinese University of Hong Kong 2014.
Includes bibliographical references (leaves 49-56).
Abstracts also in Chinese.
Title from PDF title page (viewed on 18, October, 2016).
Kam, Chon Fai = Fei xian xing xi tong de Beili qu lu / Gan Junhui.
Detailed summary in vernacular field only.
Haider, Miran. "Geometric Phases In Quantum Systems Of Pure And Mixed State." Thesis, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-48008.
Повний текст джерелаObservera att ekvationer och andra uttryck har exkluderats här och är presenterade i själva arbetet. Detta examensarbete behandlar geometriska faser i rena och blandade kvanttillsånd. I rena kvanttillstånd finner man Berrys adiabatiska behandling av den geometriska fasen (4.1.10) och Aharonov & Anandan icke-adiabatiska generaliseringav Berry fasen (4.2.8). I det blandade kvanttillstånden har Uhlmann introducerat en förlängning av den geometriska fasen som sträcker sig till det blandadekvanttillstånden (5.1.42), detta finner man i sektion 7. Senare har Sjöqvistet al. introducerat ett alternativ till att angripa geometriska faser (5.2.22) som beskrivs i sektion 6. Sjöqvist konstaterade att Uhlmannfasen är observerbar,i kvantmekanisk mening, och presenterade ett experimentelt upplägg där han visade just detta med hjälp av en interferometer. vilket senare bevisades av Du et al.[45] där de experimentella mätvärdena stämde överens med dem teoertiska (se figur 19 på sidan 56). Uhlmannfasen kan även användas för att observera topologiska "kink"-lösningar. Detta testades för 3 olika modeller; Creutz stege formationen, Majorana kedjan och SSU modellen. Det visade sig att Uhlmannfasen delades up i två regioner och var starkt beroende av temperaturen. Denna temperaturen kallades för den kritiska temperaturen Tc. Om temperaturen liggerunder eller över den kritiska temperaturen får man att Uhlmannfasen ger Π eller 0 respective.