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Lioz, Kathleen Malka. "The protagonist in the novels of Aharon Megged." Thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/25762.
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Huber, Jens [Verfasser], Aharon [Akademischer Betreuer] Wegner, and Chris-Patrick [Akademischer Betreuer] Lohmann. "Selektive Lasertrabekuloplastik: Therapieergebnis, prädiktive Faktoren und Wechselwirkung mit lokaler Therapie / Jens Huber. Gutachter: Chris-Patrick Lohmann ; Aharon Wegner. Betreuer: Aharon Wegner." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1050238737/34.
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Feinberg, Anat. "Yigal Schwartz: Maamin beli Kenessija : 4 Massot al Aharon Appelfeld [Ein Gläubiger ohne Kirche : vier Essays über Aharon Appelfeld] / [rezensiert von] Anat Feinberg." Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2010/4375/.
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Windsperger, Marianne. "Lebenswege in Traum(a)landschaften die Bukowina als Erinnerungslandschaft in ausgewählten Werken Aharon Appelfelds." Frankfurt, M. Berlin Bern Bruxelles New York, NY Oxford Wien Lang, 2009. http://d-nb.info/994710356/04.
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Furci, Guido. "L'héritage nu. Mises en fiction du "témoin historique". Primo Levi - Aharon Appelfeld - Philip Roth." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCA077.
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Pendant de nombreuses années, Aharon Appelfeld, Philip Roth et Primo Levi entretiennent une sorte de « dialogue à distance », interrompu en 1987 par la mort de ce dernier. Notre travail vise à analyser les modalités à travers lesquelles la production de ces trois écrivains – marqués de manière plus ou moins « directe » par l’histoire de la deuxième guerre mondiale et la mémoire de la Shoah – complexifie, avant tout sur le plan fictionnel, une certaine conception du témoignage, dont les enjeux esthétiques sont loin d’être anodins. Certes, dans un premier temps il a été important de reconstituer la correspondance triangulaire entre Levi, Appelfeld et Roth ; bien que fondamentale, ce n’est pas la composante philologique de notre recherche que nous avons souhaité mettre en avant, mais plutôt la pertinence d’un rapprochement de corpus en apparence distants, et pourtant liés par des questionnements analogues. Il est évident que si la possibilité de consulter, donc de disposer de documents d’archive pour la plupart inédits et d’accéder à des échanges parfois publics – quoique destinés à un auditoire en quelque sorte « communautaire » – a été précieuse afin d’alimenter la réflexion, le fait de lier de manière trop manifeste les considérations au sujet des démarches (poétiques ou politiques) de nos trois auteurs à leur complicité intellectuelle et, le cas échéant, à leur amitié aurait pu minimiser la portée de certaines observations – et suggérer de faux rapports de cause à effetMy doctoral thesis explores the relationship between literature and historical witnessing. By focusing on the works of Primo Levi, Aharon Appelfeld, and Philip Roth (authors who relate in very different ways the trauma of the Holocaust), my research aims at investigating the enmeshment of aesthetic and epistemological issues. My comparative exploration of these authors is motivated by and allows for a conceptual layering of the problem along three distinct research axes : (1) each author maintains a different degree of autobiographical involvement with the genocidal facts he evokes, ranging from maximum directness (Levi) to an oblique post hoc distance (Roth) ; (2) each author thematizes the problem by framing fictional situations in which characters have to cope with the plastic tension of narrative recollection ; (3) there is a twofold factual link between the three authors consisting in (a) explicit or covert intertextual quotations (e.g. Levi and Appelfeld become characters in Roth’s "Operation Shylock") and, more significantly, (b) an under-investigated circular correspondence in which each of them discusses at length the gains and losses of (literary) historical witnessing. The core of my project, therefore, is grounded in the long-distance conversation on the reworking of memories between Aharon Appelfeld, Philip Roth and Primo Levi – a three-way conversation that perforce ceased with Levi’s death in 1987
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Schmidt, Walter. "Balance zwischen Beruf und Familie : Ko-evolution zu effizienter und familienbewusster Führung." kostenfrei, 2009. http://deposit.d-nb.de/cgi-bin/dokserv?idn=998968285.
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Or, Tamara. "Der Odem des Menschen ist eine Leuchte des Herrn, Aharon Agus zum Gedenken, Ronen Reichman [Hg.] / [rezensiert von] Tamara Or." Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/2236/.
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Rezensiertes Werk:
"Der Odem des Menschen ist eine Leuchte des Herrn" : Aharon Agus zum Gedenken / hrsg. von Ronen Reichman. - Heidelberg : Winter, 2006. - VIII, 298 S.: Ill. - ( Schriften der Hochschule für Jüdische Studien Heidelberg ; Bd. 9)
ISBN 013555014
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Wakrat, Anath Czeresnia. "Ideologia e gerações em Aharon Megued: estudo sobre a personagem do imigrante judeu e o nativo de Israel no início do estado." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/8/8158/tde-15052013-085713/.
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O conto Yad Vashem, do escritor israelense Aharon Megued, publicado em 1955, narra a história do avô Ziskind, originário da Ucrânia, que residia em Israel. Quando Ziskind soube que sua neta Raia estava grávida, pediu que ela desse para o filho que ia nascer o nome de Mêndele, caso fosse homem. A partir daí começa a discussão sobre a escolha de um nome típico da tradição europeia, defendido pelo avô, que se apresenta como um estranho para a família, ou um nome israelense, próprio de uma ideologia sionista, exigido pela neta. Esse conflito geracional revela uma crise de identidade profunda entre o imigrante e seus descendentes que se resume no choque entre o antigo e o novo, retratando as diferentes ideologias de um povo.The tale Yad Vashem, of the Israeli writer Aharon Megued, published in 1955, tells the story of the grandfather Ziskind, from Ukraine, who resided in Israel. When Ziskind knew that his granddaughter Raia was pregnant, asked that she gave the name for her son who would be born Mendele, if he were a boy. From this, starts a discussion about the choice of a typical name of the European tradition, defended by the grandfather, who presents himself as a strange to the family, or an Israeli name, pertaining to a Zionist ideology, demanded by the granddaughter. This conflict reveals a deep identity crisis between the immigrant and his descendants which is summed up in the shock between the old and the new, showing the different ideologies of a people.
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Liestak, Roberta [Verfasser], Martin [Akademischer Betreuer] Halle, Herbert [Akademischer Betreuer] Deppe, Aharon [Akademischer Betreuer] Wegner, and Ernst J. [Akademischer Betreuer] Rummeny. "Einfluss eines schulbasierten Präventionsprojekts auf die retinale Mikrozirkulation bei Kindern / Roberta Liestak. Gutachter: Martin Halle ; Herbert Deppe ; Aharon Wegner ; Ernst J. Rummeny. Betreuer: Martin Halle." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1031514899/34.
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Meint, Peter [Verfasser], Chris-Patrick [Akademischer Betreuer] Lohmann, and Aharon [Akademischer Betreuer] Wegner. "Immunhistochemische Charakterisierung von Zellen aus dem Glaskörper-Raum in vitro - Identifizierung einer Glaskörpervorläuferzelle / Peter Meint. Gutachter: Chris-Patrick Lohmann ; Aharon Wegner. Betreuer: Chris-Patrick Lohmann." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1046939750/34.
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Tauber, Michèle. "Les langages de la mémoire au miroir des langages de la nature dans l'oeuvre d'Aharon Appelfeld." Paris 8, 2001. http://www.theses.fr/2001PA082030.
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Aharon Appelfeld, écrivain israélien contemporain, est né en 1932 à Tchernowitz où l'allemand est sa langue maternelle. Il apprend l'hébreu à 14 ans à son arrivée sur la terre d'Israe͏̈l. Figure majeure de la littérature israélienne, il se situe toutefois hors du sérail des écrivains qui dépeignent les états d'âme d'une société israélienne en mutation permanente. Appelfeld s'attache à retracer le vécu du judai͏̈sme européen d'Europe centrale tout au long du XXème siècle. Grâce au yiddish, la langue des grands-parents, matrice de la mémoire juive d'Europe centrale, il parvient à jeter un pont entre son Europe d'origine et son pays d'accueil. Il dispose alors d'un nouvel atout : la langue hébrai͏̈que puisqu'elle incarne, avec le yiddish, l'une des deux grandes langues de la littérature juive d'Europe dès la fin du XIXème siècle. Appelfeld modèle l'hébreu à son gré et y façonne des langages littéraires nouveaux : il se fait sculpteur de la langue, dans ses pleins, mais aussi dans ses manques. . .
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Teodoro, Marcio Daldin. "Efeito Aharonov-Bohm em partículas neutras." Universidade Federal de São Carlos, 2011. https://repositorio.ufscar.br/handle/ufscar/4930.
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Previous issue date: 2011-03-14Universidade Federal de Sao Carlos
In classical Physics, the motion of an electrically charged particle is affected only by the presence of a magnetic field if the particle enters a region of space in which the field is present. Meanwhile, in quantum Physics, a charged carrier can be affected by the electromagnetic vector potential ~A, even in regions where the magnetic field ~B is not present. This surprising contrast between classical and quantum Physics has been experimentally proven in several beautiful experiments in semiconducting, metallic and superconducting material systems, and has been called Aharonov-Bohm effect. More recently, however, several theoretical works have discussed the plausible existence of this effect even for neutral particles! In this PhD Thesis project it is shown the first clear experimental observation of the Aharonov-Bohm effect in neutral excitons in InAs quantum rings. Signatures of this effect appear as oscillations in the intensity of the photoluminescence emission bands with increasing magnetic fields and also depending on the dimensions of the quantum rings. These oscillations are affected by the uniaxial strain field due to the piezoelectricity of the asymmetric InAs rings, as revealed by the atomic force microscopy, transmission electron microscopy images and X-Ray Diffraction measurements using synchrotron light. A theoretical model that describes the behavior of the excitonic interference pattern and its modulation with temperature and uniaxial electric fields has been used for the interpretation of the experimental data. The detection of AB oscillations mediated by electron-hole pair correlation is a fundamental quantum mechanical effect that will trigger further studies in this area of fundamental physics as well as technological applications.
Em Física clássica, o movimento de uma partícula carregada só é afetado pela presença de um campo magnético se a partícula entrar em uma região do espaço na qual o campo está presente. Ao mesmo tempo, em Física quântica, a partícula contendo carga elétrica pode ser afetada por um potencial eletromagnético ~ A, mesmo em regiões onde o campo magnético ~B é zero. Esse contraste surpreendente entre Física clássica e Física quântica tem sido provado em interessantes experimentos em materiais semicondutores, metais e supercondutores, e tendo sido denominado efeito Aharonov-Bohm. Mais recentemente, entretanto, muitos trabalhos teóricos têm discutido a plausibilidade da existência desse efeito mesmo para partículas neutras! Nessa tese de Doutorado será demonstrado pela primeira vez a observação experimental do efeito Aharonov-Bohm em éxcitons neutros contidos em anéis quânticos de InAs. Assinaturas desse efeito aparecem como oscilações na intensidade integrada das bandas de emissão em experimentos de fotoluminescência com o aumento do campo magnético e dependem também das dimensões dos anéis. Essas oscilações são afetadas pelos campos de compressão/expansão uniaxial devido a piezoeletricidade provinda da assimetria dos anéis, como revelado pelas imagens de microscopia de força atômica, microscopia eletrônica de transmissão e difração de raios-X utilizando luz síncrotron. Um modelo teórico que descreve o comportamento no padrão de interferência excitônico e sua modulação com a temperatura e campos elétricos uniaxiais foi usado para a interpretação dos resultados experimentais. A detecção das oscilações Aharonov-Bohm mediada pela correlação do par elétron-buraco é um efeito fundamental de mecânica quântica e os estudos mostrados aqui poderão não só instigar outras investigações em Física fundamental assim como em aplicações tecnológicas.
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Hebbar, Omar. "Effet Aharonov-Bohm pour des systèmes." Nantes, 1992. http://www.theses.fr/1992NANT2041.
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L'objet de ce travail est l'étude spectrale de l'effet Aharonov-Bohm pour des opérateurs, dits du type de Bochner-Laplace, associé à un potentiel électrique et à une connexion linéaire sur un fibre hermitien au-dessus d'une variété riemannienne compacte et connexe. Dans le premier chapitre, on définit, a partir d'un chemin ferme et d'une connexion plate, une classe d'équivalence de matrices unitaires constantes appelée matrice d'holonomie. On obtient alors, une caractérisation des connexions triviales à l'aide de conditions sur cette classe. On s'intéresse ensuite au problème de comparaison des valeurs propres et on commence par regarder le cas d'un fibre trivial. Dans ce cas, l'operateur considéré est un operateur de Schrodinger avec un potentiel électrique et un potentiel magnétique (de type Yang-Mills) à valeurs matricielles. On donne alors des conditions nécessaires et suffisantes sur le potentiel magnétique, pour que l'operateur associé admette les mêmes premières valeurs propres que celui définit par le potentiel magnétique nul. Les résultats obtenus dans ce chapitre complètent et généralisent ceux de B. Helffer, I. Shigekawa pour le cas scalaire et S. Manabe-I. Shigekawa pour les systèmes. Le cas d'un fibre non nécessairement trivial est étudié dans le chapitre 3. Dans le chapitre 4, on fait une analyse semi-classique de l'effet Aharonov-Bohm dans le complémentaire d'un disque de plan.
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Pereira, Marciano. "Efeito Aharonov-Bohm : extensões auto-adjuntas e espalhamento." Universidade Federal de São Carlos, 2009. https://repositorio.ufscar.br/handle/ufscar/5812.
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Previous issue date: 2009-10-05Universidade Federal de Sao Carlos
In this work we present a study of topics related to the Aharonov-Bohm (AB) e®ect. Our framework is that of nonrelativistic quantum mechanics and we use the point of view of mathematical physics. (1) We study the solenoid of finite length and zero radius and compare their self- adjoint extensions with the known case of the solenoid of infinite length and also of zero radius in the plane. (2) By considering an infinitely long cylindrical solenoid of radius greater than zero, mainly in the plane, we present a classification of all self-adjoint SchrÄodinger operators (i.e., the possible boundary conditions on the solenoid border) that mathematically could characterize the AB operator, whose domains are contained in the natural space of twice weakly di®erentiable functions (and, of course, also square integrable). (3) We then consider the traditional Dirichlet, Neumann and Robin boundary conditions on the solenoid border and calculate and compare their scattering matrices and cross sections. Hopefully this could be used to experimentally select one of such extensions. (4) Finally, we discuss a theoretical mechanism we propose to select and so justify the usual AB hamiltonian with Dirichlet boundary conditions on the solenoid. This is obtained by way of increasing sequences of finitely long solenoids together with a natural impermeability procedure; further, it is shown that both limits commute. Such rigorous limits are in the strong resolvent sense.
Neste trabalho apresentamos um estudo de tópicos relacionados ao Efeito Aharonov- Bohm (AB). Nossa abordagem é a da mecânica quântica não-relativística e usamos o ponto de vista da física-matemática. (1) Estudamos o solenóide de comprimento ¯nito de raio zero e comparamos suas extensões auto-adjuntas com as do caso conhecido do solenóide de comprimento infinito também de raio zero no plano. (2) Considerando um solenóide cilíndrico infinito de raio maior do que zero, principalmente no plano, apresentamos uma classificação de todos os operadores de SchrÄodinger auto-adjuntos (isto é, as possíveis condições de fronteira na borda do solenóide) que matematicamente poderiam caracterizar o operador AB, cujos domínios estão contidos no espaço natural das funções duas vezes fracamente diferenciáveis (e, natural- mente, também de quadrado integrável). (3) Então consideramos as tradicionais condições de fronteira de Dirichlet, Neumann e Robin na borda do solenóide e calculamos e comparamos seus operadores de espalhamento e seções de choque. Esperamos que com tal estudo uma dessas extensões auto-adjuntas possa ser selecionada experimentalmente. (4) Final- mente, discutimos um mecanismo teórico que propomos para selecionar, e assim justificar, o usual hamiltoniano de AB com condições de Dirichlet na fronteira do solenóide. Isto é obtido por meio de uma sequência crescente de solenóides de comprimentos finitos junto com um procedimento natural de impermeabilização; além disso, mostramos que ambos os limites comutam. Tais limites rigorosos são no sentido forte do resolvente.
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Antini, Alessandro. "Fasi geometriche, fase di Berry ed effetto Aharonov-Bohm." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9127/.
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Un sistema sottoposto ad una lenta evoluzione ciclica è descritto da un'Hamiltoniana H(X_1(t),...,X_n(t)) dipendente da un insieme di parametri {X_i} che descrivono una curva chiusa nello spazio di appartenenza. Sotto le opportune ipotesi, il teorema adiabatico ci garantisce che il sistema ritornerà nel suo stato di partenza, e l'equazione di Schrödinger prevede che esso acquisirà una fase decomponibile in due termini, dei quali uno è stato trascurato per lungo tempo. Questo lavoro di tesi va ad indagare principalmente questa fase, detta fase di Berry o, più in generale, fase geometrica, che mostra della caratteristiche uniche e ricche di conseguenze da esplorare: essa risulta indipendente dai dettagli della dinamica del sistema, ed è caratterizzata unicamente dal percorso descritto nello spazio dei parametri, da cui l'attributo geometrico. A partire da essa, e dalle sue generalizzazioni, è stata resa possibile l'interpretazione di nuovi e vecchi effetti, come l'effetto Aharonov-Bohm, che pare mettere sotto una nuova luce i potenziali dell'elettromagnetismo, e affidare loro un ruolo più centrale e fisico all'interno della teoria. Il tutto trova una rigorosa formalizzazione all'interno della teoria dei fibrati e delle connessioni su di essi, che verrà esposta, seppur in superficie, nella parte iniziale.
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Khan, Siraj. "Flows between Aharony and Giveon-Kutasov dualities in 3D field theories derived from type IIB string theories." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2048419/.
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Bosonic string theory and superstring theory are briefly overviewed. Three dimensional field theories are similarly discussed, with a focus on effective $N=2$ supersymmetric theories. It is shown how to induced contributions to the Chern-Simons level of the low energy theory, by integrating out massive matter. Such effective field theories are then shown to arise from type IIB brane configurations based on the Hanany-Witten brane configuration. Strong-weak dualities are overviewed, leading to a discussion of the three dimensional strong-weak dualities: Aharony duality for theories with zero Chern-Simons level, and Giveon-Kutasov duality for theories with non-zero Chern-Simons level. In the results section, brane configurations corresponding to three-dimensional $N=2$ $U(N_{c})$ field theories with various numbers of flavour of massive matter are investigated. The resulting low energy field theories are explained, and the flows between Aharony and Giveon-Kutasov dualities are catalogued. Three dimensional $N=2$ effective field theories obtained through the inclusion of massive adjoint matter are also examined, with the flows between Aharony and Giveon-Kutasov dualities, again, catalogued. Finally, the significance of the results and the possibilities for future research, are discussed.
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Ellenberger, Catrin. "Der Aharonov-Bohm-Effekt im Mischzustand von Typ-I-Supraleitern." [S.l.] : [s.n.], 2001. http://archiv.ub.uni-marburg.de/diss/z2001/0403/.
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Ahmadi, Aphrodite. "Transmission of the electron through an asymmetric Aharonov-Bohm ring." Virtual Press, 2003. http://liblink.bsu.edu/uhtbin/catkey/1265455.
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The total transmission probability of an asymmetric Aharonov-Bohm ring with an embedded scattering center in both branches and a magnetic flux passing through its center has been investigated. The transmission is calculated from the overall scattering matrix for the ring structure determined by cascading scattering matrices without the symmetric conditions. In this model, by imposing scattering centers with different strengths to the upper and lower arms of the ring, the effects of coupling between the ring and the leads and the magnetic flux in the total transmission probability as a function of transmission phase have been observed. We find the following results from our model study: 1) in the strong coupling limit, there is no zero transmission; 2) with a constant coupling and scatterer in each branch, the transmission peaks get closer together and the transmission becomes smoother as the magnetic flux increases; and 3) in the weak coupling limit with a constant magnetic flux and elastic scattering in each arm, transmission resonances become sharper due to the localized states in the ring and the magnitude of transmission is enhanced at smaller transmission phases.For the case of a single or double barrier in one arm of the ring, the discrete energy levels of the double barrier well in one branch are controlled by the width of the well and continuous levels in the other branch are controlled by a single scattering barrier. We find a peculiar quantum transport through this system such as a symmetric Breit-Wigner (BW) and an asymmetric Fano transmission resonance. The transition from BW to Fano resonance occurs by tuning either the transmission phase of the electrons through a single barrier or the magnetic AB flux threading through the AB ring. The characteristics of the Fano line-shape resonance will be examined by the asymmetric parameter that is a measure of the degree of coupling between the discrete state and the continuum.Department of Physics and Astronomy
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Salem, Vinícius. "Estudo de Espalhamento em Sistemas Aharonov-Bohm em Espaço Cônico." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2017. http://tede2.uepg.br/jspui/handle/prefix/869.
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Previous issue date: 2017-03-13Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In the present work, it is explained in a concise way the Aharonov-Bohm (AB) Efect in the magnetic case. Possible interpretations envolving the phenomena are discussed too, through a carefull review about the theme in literature, in purpose to sumarize the diferent interpretations concerning the possible physical reality of electromagnetic potentials in physics, in special the case of the vector potential, since this work focuses in the magnetic AB eect. Also, the construction and solution of Dirac equation is studied in details for the non-relativistic limit case of an electron possessing anomalous magnetic moment (i.e., g 6=2) in a conical space. For this purpose, the self-adjoint extensions method as developed by Bulla and Gesztesy is used in order to obtain expressions for bound states energies and scattering. The self-adjoint extension parameter obtained in the study of bound states and scattering showed very plausible physical results, consonant with the literature in general, as exposed in detail in chapter four. Finally, it is discussed the role of anomaly of the electron magnetic moment in providing bound states energies, a theme rarely discussed in literature since now.
No presente trabalho, procura-se explicar de forma concisa a fenomenologia do Efeito Aharonov-Bohm (AB) magnético, bem como o sistema aplicado a partículas de spin 1/2. Também são discutidas possíveis interpretações para o fenômeno através de uma cuidadosa revisão sobre o tema na literatura, buscando sumarizar as distintas opiniões sobre a possível realidade física dos potenciais eletromagnéticos, em especial do potencial vetor, uma vez que o foco neste trabalho concentra-se no Efeito AB magnético. Posteriormente,é estudada em detalhes a construção e solução da Equação de Dirac para o caso limite não-relativístico do elétron com anomalia do momento magnético (i.e., g 6= 2) em uma topologia cônica. Para isto é utilizado o método de extensão auto-adjunta de operadores na versão desenvolvida por Bulla e Gesztesy, afím de obter expressões para as energias de estados ligados e espalhamento. O parâmetro de extensão obtido no estudo de estados ligados e espalhamento apresentou resultados físicos consistentes com a literatura em geral. Por fím, o papel da anomalia no momento magnético do elétron em proporcionar estados ligados no sistema é discutido detalhadamente, algo até então pouco abordado na literatura.
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Romano, Renan Gambale. "Efeito Aharonov-Bohm sem interação com a fronteira do solenóide." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/5891.
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Previous issue date: 2013-03-08Universidade Federal de Minas Gerais
One of the biggest problem in the mathematical modeling of the Aharonov- Bohm Effect is the interaction between the electron and the solenoid border. Such interaction translates into boundary conditions on that border, which causes great ambiguity because in principle it is not clear what the most appropriate choice. In quantum mechanics this conditions represent self-adjoint extensions of the Schrödinger operator of the problem. On the other hand, recent works has demostrated that it is possible to confine quantum particles in certain regions of Rn with magnetic fields sufficientily intense near the border of that region. Mathematically this corresponds to essentially selfadjoint Schrödinger operators, which means exemption from the particle interation with the solenoid border In this work we intend to combine the two situations mentions above to study the Aharonov-Bohm effect in the plane, adding then external magnetic fields and potentials that are suffiently intense in the solenoid border so that the related Schrödinger operator is essentially self-adjoint.
Um dos grandes problemas na modelagem matemática do efeito Aharonov- Bohm é a interação do elétron com a fronteira do solenóide. Tal interação se traduz em condições de contorno nessa fronteira, o que causa grande ambiguidade, pois em princípio não é clara qual a escolha mais adequada. Em mecânica quântica essas condições de fronteira se traduzem em extensões auto-adjuntas do operador de Schrödinger do problema. Por outro lado, trabalhos recentes têm demonstrado que é possível confinar partículas quânticas a regiões determinadas de Rn com o uso de campos magnéticos suficientemente intensos nas fronteiras dessas regiões. Matematicamente isso corresponde a operadores de Schrödinger essencialmente auto-adjuntos, o que significa a isenção de interação da partícula com a fronteira. Neste trabalho pretendemos combinar as duas situações mencionadas acima para estudar o efeito Aharonov-Bohm no plano, adicionando então campos magnéticos e potenciais externos que sejam suficientemente intensos na fronteira do solenóide de modo que o operador de Schrödinger associado seja essencialmente auto-adjunto.
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Xu, Lingling. "Spin-orbit or Aharonov-Casher edge states in semiconductor systems." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/74997.
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We present studies of edge states induced by the Aharonov-Casher vector potential or Rashba-type spin-orbit interaction using quantum transport in InGaAs/InAlAs herterostructures. The Aharonov-Casher effect is electromagnetically dual to the Aharonov-Bohm effect and is predicted to lead to edge states in a parabolic confinement at two-dimensional sample edges. As a narrow gap material, InGaAs has a low effective mass, high mobility, and strong spin-orbit interaction, which indicate that it can be used as a good material to detect the Aharonov-Casher effect or SOI interaction. Using InGaAs, we measured the magnetoresistance in a quantum antidot in narrow short channels in a tilted magnetic field. The fine structure (mT spacing) observed in the magnetoresistance indicate a probable energy spacing between AC edge states. We also fabricated side-gate channel structures in InGaAs/InAlAs quantum wells and investigated the values of the Rashba spin-orbit coupling constant α using the weak antilocalization analysis as a function of the side-gate voltage. We take the effect of the finite width into account and find the corrected values. With the simulation of electric fields in the wide channel and narrow channel, we found that the electric field components can be changed using side-gate voltages. While our results do not indicate which electric field component is responsible, the data indicate that the deduced spin-orbit strength values in a narrow channel are tunable by the side-gate voltage.Ph. D.
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Vargas, Barroso Aharón Jesús [Verfasser], and Wolfgang [Akademischer Betreuer] Gerstacker. "Design and Implementation Aspects of Multilevel Codes in Hierarchical Broadcasting Communications / Aharón Jesús Vargas Barroso. Betreuer: Wolfgang Gerstacker." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2011. http://d-nb.info/1016569092/34.
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Araujo, Vanilse da Silva. "Condições de Contorno mais Gerais no Espalhamento Aharonov-Bohm de uma Partícula de Dirac em Duas Dimensões: Conservação da Helicidade e da Simetria de Aharonov-Bohm." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-28112013-105008/.
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Nessa tese, mostramos que a Hamiltoniana H e o operador helicidade de uma partícula de Dirac que se movimenta em duas dimensões na presença de um tubo de fluxo magnético infinitamente fino na origem admitem, cada um, uma família de quatro parâmetros de extensões auto-adjuntas. Para cada extensão correspondem condições de contorno a serem satisfeitas pelas auto-fuções na origem. Apesar dos operadores H e formalmente comutarem antes da especificação das condições de contorno, para garantirmos a conservação da helicidade, não é suficiente obtermos as mesmas condições de contorno para ambos os operadores, ou seja, não é suficiente a determinação de um domínio comum a ambos. Mostramos que, para certas relações entre os parâmetros das extensões satisfeitas, é possível a determinação dos domínios mais gerais onde ambos os operadores H e são auto-adjuntos e onde a helicidade é conservada, simultaneamente com a preservação da simetria de Aharonov-Bohm ( + 1), onde é o fluxo magnético em unidades naturais. Nossos resultados implicam que, nem a conservação da helicidade nem a simetria de Aharonov-Bohn, resolvem o problema da escolha da condição de contorno fisicamente correta.We show that both the Hamiltonian H and the helicity operator of a Dirac particle moving in two dimension in the presence of an infinitely thin magnetic flux tube admit each a four- parameter family of self-adjoint extensions. Each extension is in one-to-one correspondence with the boundary conditions (BC\'s) to be satisfied by the eigenfunctions at the origin. Althou- gh the actions af these two operators commute before specification of boundary conditions, to ensure helicity conservation it is not sufficient to take the same BC\'s for both operators. We show that, given certain relations between the parameters of the extensions it is possible to write down the most general domain where both operators H and are self-adjoint with heli- city conservation and also Aharonov-Bohm symmetry ( + 1) preserved, where is the magnetic flux in natural units. The continuity of the dynamics is also obtained. Our results im- ply that neither helicity conservation nor Aharonov-Bohm symmetry by themselves solves the problem of choosing the \"physical \"boundary conditions for this system.
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Kim, Ji S. "Electron transport through the double quantum dots in Aharonov-Bohm rings." Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1319544.
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We numerically investigate a total transmission probability through QDs embedded in an AB ring. The QDs are formed by delta function-like double potential barriers and a magnetic flux is penetrated in the center of the ring. In particular, we study the coupled double-QDs in series and non-coupled double-QDs in parallel in an AB ring. In each model, we show the total transmission probability as a function of QD size and electron incident energy, and present the transmission amplitude on the complex-energy plane. Of interest is the change and progression of Fano resonances and corresponding zero-pole pairs on the complex-energy plane with magnetic flux in the center of the ring.To accomplish this, we analytically solve the scattering matrix at each junction and the transfer matrix through the arms of the ring using Schrodinger equation for the delta function barriers. Then, the total transmission probability is obtained as a function of electron energy and magnetic flux by cascading these matrices. Finally, the solutions of the analytical equations and the graphical output of the transmission characteristics in the system will be obtained numerically by using Mathematica programs run on desktop computers.Department of Physics and Astronomy
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Lee, Wai-Tung. "Neutron scalar Aharonov-Bohm effect and spin density waves in chromium /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901258.
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Roh, Chung-Hee. "Electron transport through double quantum dots in an Aharonov-Bohm ring." Muncie, Ind. : Ball State University, 2008. http://cardinalscholar.bsu.edu/382.
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Silva, Carlos Alberto Stechhahn da. "\"Efeito Aharonov-Bohm não-comutativo para partículas relativísticas de spin 1/2\"." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-02042007-125704/.
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Este trabalho destina-se ao estudo de modificações no espalhamento de Aharonov-Bohm para partículas relativísticas com spin 1/2, devido à não comutatividade do espaço, em 2+1 dimensões. As correções para o potencial de Aharonov-Bohm, sendo muito singulares, levam, em geral, ao aparecimento de divergências na expansão perturbativa em torno da teoria livre. Usando, então, como ponto de partida a solução exata da versão comutativa, determinamos, na aproximação de fluxo pequeno, a amplitude invariante, seção de choque diferencial e total, com as divergências eliminadas.In this work we study modifications in the Aharonov-Bohm effect for relativistic spin 1/2 particles due the non-commutativity of space in 2+1 dimensions. The corrections for the Aharonov-Bohm potential originated from the non-commutativity of the underlying space are very singular, producing the appearance of divergences in the perturbative expansion around the free theory. Working with the pertubation around the exact solution of the commutative version of the problem, we determine then, in the small flux approximation, the invariant amplitude, and the corrections to the differential and total cross sections with all divergences eliminated.
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Costa, Ramon Francescolli. "EXTENSÃO AUTOADJUNTA DO HAMILTONIANO DO SISTEMA DE AHARONOV-BOHM COM MOMENTO MAGNÉTICO ANÔMALO." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2016. http://tede2.uepg.br/jspui/handle/prefix/854.
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Previous issue date: 2016-03-04Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In this work we present the Aharonov-Bohm effect, as well as its implications. We also present the self-adjoint extension, an important tool in quantum mechanics. This work's main objective is to investigate the relation between the self-adjoint extension parameter and the Aharonov-Bohm system's parameters. Of particular interest is the relation between the self-adjoint extension parameter and the electron's anomalous magnetic dipole moment. This is done by comparison between two self-adjoint extension methods: Bulla-Gesztesy's and Kay-Studer's. We obtain the mathematical relation between the aforementioned quantities and conclude that the chosen methods are suitable to accomplish our goals.
Neste trabalho é apresentado o efeito e sistema de Aharonov-Bohm, além de suas implicações. Trata-se também da extensão autoadjunta de operadores em mecânica quântica. O principal objetivo é a investigação da relação entre o parâmetro da extensão autoadjunta do Hamiltoniano do sistema de Aharonov-Bohm, que tem origem matemática, e a física desse sistema. Interesse particular é dado à busca da relação entre o parâmetro da extensão e a anomalia do momento magnético do elétron. Para tal são usados dois métodos de extensão autoadjunta: o de Bulla-Gesztesy e o de Kay-Studer. A expressão matemática procurada é obtida, além de expressões para as energias dos estados ligados do sistema. Conclui-se que os métodos utilizados são adequados para atingir os objetivos propostos.
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Sandström, Martin. "Path Integrals and Quantum Mechanics." Thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-110026.
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In this thesis we are investigating a different formalism of non-relativistic quantum mechanics called the path integral formalism. It is a generalization of the classical least action principle. The introduction to this subject begins with the construction of the path integral in terms of the idea of probability amplitudes whose absolute square gives the probability of finding a system in a particular state. Then we show that if the Lagrangian is a quadratic form one needs only to calculate the classical action besides from a time-dependent normalization constant to find the explicit expression of the path integral. We look in to the subject of two kinds of slit-experiments: The square slit, the single- and the double-Gaussian slit. Also, the propagator for constrained paths is calculated and applied to the Aharonov-Bohm effect, which shows that the vector potential defined in classical electrodynamics have a physical meaning in quantum mechanics. It is also shown that the path integral formulation is equivalent to the Schrödinger description of quantum mechanics, by deriving the Schrödinger equation from the path integral. Further applications of the path integral are discussed.I detta fördjupningsarbete undersöker vi en annan formalism av icke-relativistisk kvantmekanik kallad banintegral formalismen. Det är en generalisering av den klassiska verkansprincipen. Introduktionen till detta ämne börjar med konstruktionen av banintegralen i termer av sannolikhetsamplituder vars absolutbelopp i kvadrat ger sannolikheten av att finna ett system i ett särskilt tillstånd. Sedan visar vi att om Lagrangianen är av kvadratisk form så krävs endast en beräkning av den klassiska verkan förutom en tidsberoende normaliseringskonstant för att finna ett uttryck för banintegralen. Vi ser på två olika typer av spaltproblem: Den kantinga spalten, enkel- och dubbel Gaussisk spalt. Vi beräknar dessutom propagatorn för banor med restriktioner och applicerar detta på Aharonov-Bohm effekten, som visar att den klassiska vektorpotentialen som definierad i klassisk elektrodynamik har en fysikalisk mening i kvantmekaniken. Vi visar också ekvivalensen av banintegralformalismen med Schrödingerekvationen genom att härleda Schrödingerekvationen från banintegralen. Andra applikationer av banintegralen diskuteras.
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Tan, Weichao. "Electron states in low dimensional structures." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294478.
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Meresse, Cédric. "Contribution à l'analyse de la dynamique quantique dans des systèmes de Hall en présence d'un flux Aharonov-Bohm dépendant du temps." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2010. http://tel.archives-ouvertes.fr/tel-00541689.
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Le sujet de cette thèse est d'étudier la dynamique quantique d'une particule évoluant dans le plan sous l'influence de champs magnétique et électrique croisés. Dans le cas où ce système est actionné par un flux Aharonov-Bohm dépendant du temps, nous présenterons un théorème adiabatique basé sur une analyse spectrale fine en l'absence d'un potentiel électrique. Pour le cas sans champ extérieur et avec un petit potentiel électrique, nous présentons deux résultats. Premièrement, nous prouvons pour des potentiels arbitraires que la dynamique effective donne une approximation au premier ordre pour des temps longs. Ensuite, nous montrons que pour une classe de potentiels lisses et petits, nous pouvons construire une constante du mouvement non triviale. Pour cela, nous prouvons que l'hamiltonien est unitairement équivalent à un hamiltonien effectif commutant avec l'observable de l'énergie cinétique. Pour démontrer cela, nous utilisons un algorithme de diagonalisation partielle.
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Schelter, Jörg [Verfasser], and Björn [Akademischer Betreuer] Trauzettel. "The Aharonov-Bohm effect and resonant scattering in graphene / Jörg Schelter. Betreuer: Björn Trauzettel." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://d-nb.info/1029661707/34.
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Dauber, Jan [Verfasser], Christoph [Akademischer Betreuer] Stampfer, and Jörg Hendrik [Akademischer Betreuer] Bluhm. "Aharonov-Bohm oscillations in ballistic graphene rings / Jan Dauber ; Christoph Stampfer, Jörg Hendrik Bluhm." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1193181429/34.
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FAVARATO, C. C. "Um Estudo Sobre a Fase Geométrica de Berry e o Efeito Aharonov-Bohm Dual." Universidade Federal do Espírito Santo, 2014. http://repositorio.ufes.br/handle/10/7457.
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Previous issue date: 2014-11-28Neste trabalho, nos preocupamos em fazer uma revisão da literatura que aborda a chamada fase geométrica de Berry. Um assunto relativamente recente, que vem sendo empregada em várias áreas da física. Para isso, nos utilizamos de uma série de referências, das quais, muitas foram essenciais para a fundamentação teórica desta dissertação. Num primeiro momento, nos concentramos no estudo da evolução temporal de sistemas quânticos governados por operadores Hamiltonianos cuja dependência temporal manifestasse por meio de um conjunto de parâmetros chamados de campos clássicos. A aproximação adiabática, considerada durante o processo de cálculo dessas fases, é justificada matematicamente quando demonstrado o teorema adiabático. Sob essas condições, reobtemos as fases geométricas - fase de Berry - associadas a esses sistemas em diferentes representações, cada uma delas exibindo sua particularidade. Por fim, como um caso particular de fase geométrica, estudamos do ponto de vista das transformações de dualidade das equações de Maxwell, o efeito Aharonov-Bohm dual, extraindo a fase geométrica de Berry associada a dinâmica do monopolo magnético na presença do potencial vetor elétrico.
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Shi, Zheng. "Conductance of junctions of multiple interacting quantum wires and long Aharonov-Bohm-Kondo rings." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62224.
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In this thesis, we calculate the linear dc conductance of two types of multi-terminal interacting systems: junctions of interacting quantum wires attached to Tomonaga-Luttinger liquid (TLL) leads, and closed and open long Aharonov-Bohm-Kondo (ABK) rings. In both cases, we obtain corrections to the non-interacting Landauer formula, arising from interactions in the TLL leads and the quantum dot in the Kondo regime respectively.
In junctions of interacting quantum wires, if the wires are attached to Fermi liquid (FL) leads, the conductance is formally given by the Landauer formula with renormalized single-particle S-matrix elements. If, however, the wires are attached to TLL leads, i.e. the interaction does not vanish even in the leads, the conductance has an additional contribution dependent on the interaction strength in the leads. We calculate this additional contribution both at the first order in interaction and in the random phase approximation, and heuristically relate the FL conductance to the TLL conductance through a "contact resistance" between an FL lead and a TLL wire.
In long ABK rings, where the interaction is due to spin-flip scattering at a quantum dot in the Kondo regime, the linear dc conductance consists of two parts: a disconnected part of the Landauer form, and a connected part that can be approximately eliminated at low temperatures. For a closed long ABK ring, where the electric current is conserved in the ring, the high-temperature conductance has qualitatively different behaviors for temperatures greater than and lower than the characteristic energy scale v_F /L, where v_F is the Fermi velocity and L is the ring circumference. Meanwhile, for an open long ABK ring where electrons may leak into the side leads coupled to ring arms, as long as the ring arms have both small transmission and small reflection, the ring behaves as a two-path Aharonov-Bohm interferometer, and we predict the observation of a π/2 phase shift due to scattering off the Kondo singlet formed at low energies around the impurity spin.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Schelter, Jörg Alexander Jürgen [Verfasser], and Björn [Akademischer Betreuer] Trauzettel. "The Aharonov-Bohm effect and resonant scattering in graphene / Jörg Schelter. Betreuer: Björn Trauzettel." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-74662.
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Richard, Alain. "La vie et l'oeuvre du poete iranien mehdi akhavan sales -(m. Ommid 1928-1990)- suivi de cet avesta (az in avesta), presentation et traduction alain richard." Paris 3, 1998. http://www.theses.fr/1998PA030141.
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La vie et l'oeuvre du poete iranien mehdi akhavan sales sont presentees dans cette these a partir de la traduction en francais d'az in avesta, oeuvre fonda- mentale dans la production du poete. La premiere partie, largement documentee est une biographie fondee sur la chronologie des oeuvres et sur les temoignages de certains amis du poete (yadollah qorai, abd-ol 'ali dastqeyb. . . ). Une deuxieme partie presente le debat sur "she'r-e-now", la poesie nouvelle. Une etude stylistique offre une comparaison avec la poetique de nima yushij. La contribution de mehdi akhavan sales, est presentee au regard de la critique iranienne. La presentation et la traduction d'az in avesta en francais (25 poemes et une longue postface) constituent la troisieme partie de cette these, suivie d'une bibliographie et d'un glossaireThe life an the works of iranian poet mehdi akhavan sales reviewed in this thesis are based on the complete translation in french of the poet's main work : az in avesta. The first part, well-documented, is a biography structured around the chronological order of the poems, and presents testimony of some author's friends (qorai, dastqeyb. . . ). The second part highlights the debat about she'r-e-now, the new poetry. A stylistic study provides a comparaison with nima yushij's poetry. Next is included a resume of iranian critical opinion regarding the contribution of his litterary work. In the third part is a presentation and a french translation of "az in avesta" (twenty fives poems and a very long postface), complete by a bibliography and a glossary
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Silva, Júlio Eloísio Brandão da. "Níveis de Landau-Coriolis." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/9515.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Inertial effects, such as Coriolis’ and centrifuge forces play an interesting role on classical mechanics and currently has been largely used in quantum mechanics, including in analogies with the electromagnetic effects. However, these analogies between the inertial forces on the massives particules and the electromagnetic forces on charged particles is not new. They were explored by Aharonov and Carmi in 1970 and by Tsai and Nelson in 1988 in the context of a rotational quantum phase like an Aharonov-Bohm phase. Based in this analogy, Dattoli and Quattromini, introduced Coriolis’ analogue quantum states to Landau levels. In 1915, Barnett had already published a paper about magnetization due to rotation which recently had a renewed interest applyed to nanostructures. A rotational analogy of the classical Hall effect was proposed and rotational inertial forces were studied in spintronic. Energy spectra like Landau levels appear under the action of Coriolis forces when the centrifuge force acting on free electrons is compensated by a radial electric field. In this work, we will demonstrate effects caused by rotation and magnetic field in a spinning conductor disc. We will study both the electromagnetic and inertial interactions simultaneously. Some values to the relation between the magnetic field and the rotation will be chosen and this will result in Landau-like levels to a system with resultant force composed by Coriolis’ and magnetic forces. A similar behavior for the energy spectrum will be found without a magnetic force composing the resultant force.
Efeitos inerciais, tais como a força centrífuga e a de Coriolis, desempenham um papel importante na mecânica clássica e atualmente têm sido amplamente explorados na mecânica quântica, inclusive em analogias com efeitos eletromagnéticos. No entanto, essas analogias entre as forças inerciais sobre partículas massivas e as forças electromagnéticas sobre partículas carregadas não é nenhuma novidade. Elas foram exploradas por Aharonov e Carmi em 1970 e por Tsai e Neilson em 1988 no contexto de uma fase quântica rotacional similar à fase de Aharonov- Bohm. Baseados nessa mesma analogia, Dattoli e Quattromini introduziram estados quânticos de Coriolis análogos aos níveis de Landau. Em 1915, Barnett já havia publicado um artigo sobre magnetização devido à rotação o qual teve recentemente um interesse renovado aplicado a nanoestruturas. Um análogo rotacional do efeito Hall clássico foi proposto e os efeitos inerciais da rotação foram estudados em spintrônica. Espectros de energia tipo níveis de Landau aparecem sob a ação da força de Coriolis quando a força centrífuga agindo nos elétrons livres é compensada por um campo elétrico radial. Neste trabalho, vamos demonstrar efeitos devido à rotação e ao campo magnético em um disco condutor girante. Estudaremos as interações eletromagnéticas e inerciais simultaneamente. Alguns valores para a relação entre o campo magnético e a rotação serão escolhidos e resultarão em níveis tipo Landau para um sistema com força resultante composta pelas forças de Coriolis e magnética. Um mesmo comportamento para o espectro de energia será obtido sem força magnética compondo a força resultante.
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Perkins, Abigail C. "Electron spin-polarization via Zeeman and Aharonov-Bohm effects in a double quantum dot ring." CardinalScholar 1.0, 2009. http://liblink.bsu.edu/uhtbin/catkey/1540705.
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A nanoscale Aharonov-Bohm (AB) ring with a quantum dot (QD) embedded in each arm is investigated analytically to provide electron transmission characteristics. A parallel magnetic field provides Zeeman splitting of the QD energy levels. Combined Zeeman energy level splitting and AB-effects occur with a perpendicular field. In our device, the AB-ring interferometer, Zeeman splitting of the QD energy levels creates regions of parameter space in which the electron transmission is highly spin-polarized. In addition to Zeeman splitting caused by a parallel magnetic field, combined Zeeman energy level splitting and AB-interference effects occur with a perpendicular field. The weighted spin-polarization function is calculated and presented as a function of magnetic field and electron energy. Due to a unique parameter regime in which the AB-oscillations show extreme sharpening [1], the electron transmission can be tuned to produce spin-polarized currents which can be switched and controlled by small changes of external fields.Introduction -- AB-oscillations and resonances in a double quantum dot ring -- Results for combined Zeeman and AB effects -- Spin-polarization.
Department of Physics and Astronomy
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Anacleto, Marcos Antonio. "Correção não-comutativa para o efeito Aharonov-Bohm: uma abordagem da teoria quântica de campos." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-11032014-165201/.
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Estudamos as teorias não-relativísticas e não-comutativas de campos de spin zero e l/2 acoplado minimamente com o campo ele Chern-Simons em 2+ 1 dimensões. Na situação comutativa o modelo escalar foi usado para simular o efeito Aharonov-Bohrn na abordagem da teoria de campos. Na teoria escalar verificamos que, contrariamente ao resultado comutativo, a inclusão ele urna auto--interação quártica do campo escalar não ó necessária para garantir a renormalização ultravioleta do modelo. Entretanto, para obter um limite comutativo analítico a presença ele uma auto-interação quártica é exigida. Mostramos para o caso ele partículas ele spin 1/2 que a contribuição em um laço para a matriz ele espalhamento contendo o termo de Pauli é puramente não--planar. O termo de Pauli desempenha a mesma função ela auto-interação quártica como no caso escalar. Para valores pequenos do parâmetro da não--comutatividade determinamos as correções para o espalhamento Aharonov-Bohm e provamos que, até ordem de um laço, os modelos são livres de singularidades ultravioleta/infravermelha.We study noncommutative nonrelativistic theories of spin 0 and 1/2 field coupled to thc Chern-Sirnons field in 2+1 dimensions. In the commutative situation the scalar model has been used to simulate the Aharonov-Bohm effect in the field theory context. We verified that, contrarily to the commutative result, the inclusion of a quartic self-interaction of the scalar field is not necessary to secure the ultraviolet renormalization of the model. However, to obtain a smooth commutative limit the presence of a quartic gauge invariant self-interaction is required. For the case of spin 1/2 particles we show that the one-loop contributions to the that scattering matrix the which contain the Pauli\'s term are purely nonplanar. Thc Pauli\'s term plays the same role of a quartic self-interaction in the scalar case. For small values of the noncommutative parameter we fix the corrections to the Aharonov-Bohm scattering and prove that up to one-loop the models are free from dangerous infrared/ultraviolet divergences.
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Malacarne, Luís Carlos. "Estudos sobre Teorias com Chern-Simons: Equivalência entre Modelos e Efeito Aharonov-Bohm Não-Abeliano." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/43/43132/tde-24022014-110739/.
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O objetivo desta tese é estudar alguns modelos contendo o termo de Chern-Simons, cuja presença induz várias características tais como massa topológica e spin fracionário. Iniciamos tratando o problema da equivalência entre os modelos Auto-Dual minimamente acoplado com o campo de Dirac, e o modelo de Maxwell-Chern-Simons com um acoplamento magnético com férmions. Nós mostramos que os setores fermiônicos dos modelos somente são equivalentes se adicionarmos uma auto-interação tipo Thirring. Em seguida, analisamos o efeito Aharonov-Bohm não-Abeliano para partículas de spin 0 e ½. Partindo da teoria quântica de campos relativística no gauge de Coulomb e usando o procedimento do corte intermediário, para separar o momento de integração nas regiões de baixa e alta energia, nós obtemos o limite não relativístico dos modelos. Desta forma as correções radiativas, tais como polarização do vácuo e correção de vértice, são automaticamente incluídas. Finalizando estudamos algumasThe aim of this work is to study some models with Chern-Simons term~ which induces several properties such as l-opological mass and fractional spin. We start studying the exact equivalence between the Self-Dual model minimally coupled to a Dirac field and the Maxwell-Chern-Simons model witb non-minimal magnetic coupling to fermions. Weshow that the fermions sectors of the models are equivalent only if a Thirring like interaction is included. Next we analyze the non-Abelian Aharonov-Bohm scattering for 0 and 1/2 spin particles. Starting Crom the relatistic quantum field theory and using 8 Coulomb gauge rormalism the one loop renorrnalizalion is implemented. Trough the introduction of na intermediaf) cutoff, separating the regions of high and low integration momentum the nonrelativistic Umit is derived. In this approach CJuant.um field theory vacuum polarization and anomalous magnetic momentum are automatically incorporated. Va also study some properties of the chat\'ged one spin particles interacting wit.h Chern Simons field.
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Romano, Renan Gambale. "Confirmação matemática do efeito Aharonov-Bohm no modelo sem interação com a fronteira do solenóide." Universidade Federal de São Carlos, 2016. https://repositorio.ufscar.br/handle/ufscar/7284.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
We study the Aharonov-Bohm effect model by adding a scalar potential in the initial Hamiltonian. Using known techniques of quantum confinement, we show that under certain conditions of divergence on this potential, the family of self-adjoint extensions is reduced to a single operator, which would then be the Schrödinger operator for this situation. The lack of boundary conditions to define this operator is interpreted as no particle interaction with the boundary of the solenoid. We checked the possible manifestation of the Aharonov-Bohm effect in this model without interaction with the solenoid border by studying the dependence of the first eigenvalue associated with the Schrödinger operator with respect to a parameter directly related to the magnetic flux by the solenoid. We have shown that this dependence is non-trivial and periodic, which strictly confirms the Aharonov-Bohm effect for this situation. We also study some particular cases whose explicit solution can be achieved, the solenoid with zero radius in a limited and unlimited region of the plane.
Estudamos o modelo de efeito Aharonov-Bohm adicionando um potencial escalar no Hamiltoniano inicial. Usando técnicas conhecidas de confinamento quântico, demonstramos que, sob certas condições de divergência sobre este potencial, a família das extensões autoadjuntas se reduz a um único operador, o qual seria então o operador de Schrödinger para esta situação. A falta de condições de fronteira para a definição deste operador é interpretada como não interação da partícula com a fronteira do solenoide. Verificamos a possível manifestação do efeito de Aharonov-Bohm neste modelo sem contato com a fronteira do solenóide estudando a dependência do primeiro autovalor associado ao operador de Schrödinger com relação a um parâmetro diretamente relacionado ao fluxo magnético pelo solenóide. Demonstramos que esta dependência é não trivial e periódica, o que confirma rigorosamente o efeito de Aharonov-Bohm para este modelo. Estudamos também alguns caso particulares cuja resolução explícita pode ser obtida, como o solenóide com raio nulo numa região limitada e ilimitada do plano.
FAPESP: 2012/21480-8
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Melo, Jilvan Lemos de. "Quantização de Landau para quadrupolo elétrico." Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/5720.
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Previous issue date: 2010-10-22Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this work we discuss the importance of the quantum phases using the Aharonov-Bohm Effect for charged particles and neutral particles with magnetic dipole moment(Aharonov- Casher Effect) and electric dipole moment(He-McKellar-Wilkens Effect) and atoms with electric quadrupole moment. It takes advantage of the initial study of such systems to show the emergence of Landau levels in the dynamics of a particle in two situations: when the particle is charged and when it is neutral. In the case of a neutral particle is considered that it possesses electric dipole moment. In addition it is the first time which is approached a neutral atom with electric quadrupole moment.
Neste trabalho discutimos a importância das fases quânticas usando o Efeito Aharonov-Bohm para partículas carregadas e partículas neutras com momento de dipolo magnético (Efeito Aharonov-Casher) e momento de dipolo elétrico (Efeito He-McKellar-Wilkens), e átomos com momento de quadrupolo elétrico. Tira-se vantagem do estudo inicial de tais sistemas para mostrar a emersão de níveis de Landau na dinâmica de uma partícula em duas situações: quando a partícula está carregada e quando ela é neutra. No caso de uma partícula neutra é considerado que esta possui momento de dipolo elétrico. Além disso é a primeira vez que é abordado um átomo neutro com momento de quadrupolo elétrico.
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Schütz, Georg [Verfasser], and Alexander [Akademischer Betreuer] Stibor. "Optimierung und Charakterisierung eines Biprisma-Interferometers für die Aharonov-Bohm Physik / Georg Schütz ; Betreuer: Alexander Stibor." Tübingen : Universitätsbibliothek Tübingen, 2019. http://d-nb.info/1180382617/34.
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Gillot, Jonathan. "Expériences en interférométrie atomique : application à la mesure des phases géométriques He-McKellar-Wilkens et Aharonov-Casher." Phd thesis, Université Paul Sabatier - Toulouse III, 2013. http://tel.archives-ouvertes.fr/tel-00958827.
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La famille des phases géométriques d'origine électromagnétique est formée de la phase Aharonov-Bohm (AB) prédite en 1959 et des phases Aharonov-Casher (AC) et He-McKellar-Wilkens (HMW) prédites en 1984 et 1993-1994 respectivement. Si la phase AB et la phase AC ont été rapidement observées expérimentalement, la phase HMW n'a été détectée qu'en 2011 par notre équipe au cours de la thèse de S. Lepoutre. La phase AC apparaît quand un dipôle magnétique interagit avec un champ électrique perpendiculaire à sa vitesse et au dipôle et la phase HMW, reliée à la phase AC par la dualité de Maxwell, apparaît quand un dipôle électrique interagit avec un champ magnétique perpendiculaire à sa vitesse et au dipôle. Cette thèse présente la mesure de ces deux phases à l'aide d'un interféromètre atomique de Mach-Zehnder fonctionnant avec l'atome de lithium 7Li et utilisant la diffraction de Bragg par des ondes stationnaires laser. Dans ce manuscrit, je commence par présenter l'interféromètre atomique puis je décris le pompage optique du jet atomique de lithium dans un seul sous-niveau Zeeman-hyperfin F = 2,MF = +2 (ou −2) et la caractérisation de son efficacité qui est voisine de 95 ± 5%. Ce pompage a rendu indétectables les effets systématiques qui avaient compliqué la première détection de la phase HMW. Je présente ensuite les mesures des phases AC et HMW qui sont petites, de l'ordre de quelques dizaines de milliradians dans les conditions de cette expérience, avec une incertitude inférieure 10%. En variant la vitesse moyenne des atomes entre 750 m/s et 1500 m/s, nous avons observé que ces deux phases sont bien indépendantes de la vitesse ce qui prouve leur caractère géométrique.
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AZEVEDO, Frankbelson dos Santos. "Dinâmica quântica de uma partícula neutra em campos elétricos externos." Universidade Federal de Campina Grande, 2015. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1982.
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Capes
Este trabalho tem por objetivo estudar a dinâmica quântica planar de partículas neutras de spin-1/2 na presença de campos elétricos. A priori uma partícula com carga nula não devia interagir com campos eletromagnéticos, mas ao admitir partículas possuindo momento de dipolo magnético, vemos que a interação é possível. Tal estudo acontece através da equação de Dirac com acoplamento não mínimo, onde o termo de interação leva em conta o momento de dipolo magnético, spin da partícula e campo eletromagnético. A partir dessa equação, derivamos e resolvemos duas equações diferenciais de primeira ordem, mostrando que as soluções estão atreladas ao spin. As soluções para o efeito Aharonov-Casher é discutida em detalhes pela primeira vez neste trabalho. Também derivamos uma equação diferencial de segunda ordem, a partir da qual obtivemos o níveis de energia para uma partícula movimentando-se em um caminho circular de raio constante. Além disso, usando o método de extensão auto-adjunta, encontramos funções de onda de estados ligados e níveis de energia para o espaço completo, incluindo a região r = 0. Os níveis de energia obtidos são análogos aos níveis de Landau, e mostram uma dependência com o parâmetro projeção de spin. Por fim, tomamos o limite não relativístico para o espaço completo.
This work aims to study the planar quantum dynamics of neutral particles of spin- 1/2 in the presence of electric fields. A priori a particle with null charge should not interact with electromagnetic fields, but to admit particles having magnetic dipole moment, we see that the interaction is possible. Such study happen through the Dirac equation with non-minimal coupling, where the interaction term takes into account the magnetic dipole moment, spin of the particle and electromagnetic field. From this equation, we derive and solve two differential equations of first order, showing that the solutions is linked to spin. The solutions to the Aharonov-Casher effect is discussed in detail for the first time in this study. We also derive a differential equation of second order, from which we obtained the energy levels for a particle moving in a constant radius circular path. In addition, using the self-adjoint extension method, we find wave functions of bound states and energy levels to the full space, including the region r = 0. The Energy levels obtained are analogous to Landau levels, and show a dependence on the spin projection parameter. Finally, we take the non-relativistic limit for the full space.
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Lillianfeld, Robert Brian. "Experimental Observation of Geometric Phases in Narrow-Gap Semiconductor Heterostructures." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/26889.
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We have studied the electron quantum phase by fabricating low dimensional (d â ¤ 2) mesoscopic interferometers in high-quality narrow-gap semiconductor (NGS) heterostructures. The low effective-mass electrons in NGS heterostructures enable observation of delicate quantum phases; and the strong spin-orbit interaction (SOI) in the systems gives us means by which we can manipulate the quantum-mechanical spin of these electrons through the orbital properties of the electrons. This enables the observation of spin-dependent phenomena otherwise inaccessible in non-magnetic systems. We have performed low temperature (0.4 K â ¤ T â ¤ 8 K), low noise (â V ~ 1μV ) transport measurements, and observed evidence of Aharonov-Bohm (AB) and Alâ tshuler-Aronov-Spivak (AAS) quantum oscillations in meso- scopic devices that we fabricated on these NGSs. Our measurements are unique in that we observe both AB and AAS in comparable magnitude in ballistic networks with strong SOI. We show that, with appropriate considerations, diffusive formalisms can be used to describe ballistic transport through rings, even in the presence of SOI. This work also contains an introduction to the physics of geometric phases in mesoscopic systems, and the experimental and analytic processes through which these phases are probed. A discussion of the results of our measurements presents the case that quantum interferometric measurements of geometric phases can be understood quite thoroughly, and that these measurements may have deeper utility in discovery than has yet been recognized.Ph. D.
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Smirnov, Andrei Anatolyevich. "A equação de Dirac com uma superposição do campo de Aharonov-Bohm e um campo magnético uniforme colinear." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-07082013-160530/.
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Neste trabalho é estudada a equação de Dirac com uma superposição do campo de Aharonov-Bohm (AB) e de um campo magnético colinear uniforme, que nós chamamos de campo magneto-solenoidal (MS). Usando a teoria de von Neumann das extensões auto-adjuntas de operadores simétricos, nós construímos no caso de 2+ 1 dimensões uma família uni paramétrica de hamiltonianos de Dirac auto-adjuntos especificados pelas condições de contorno no solenóide AB, e encontramos o espectro e as auto-funções para cada valor do parâmetro de extensão. Em seguida, reduzimos o problema em 3+ 1 dimensões ao problema em 2+ 1 dimensões pela escolha apropriada do operador de spin, o que permite realizar todo o programa de construção de extensões auto-adjuntas, e assim, também permite obter os espectros e auto-funções em termos do problema em 2+1 dimensões. Ademais, nós apresentamos o método reduzido de extensões auto-adjuntas do hamiltoniano radial de Dirac com o campo MS. Depois nós consideramos o caso regularizado do solenóide de raio finito. Nós estudamos a estrutura das autofunções e a sua dependência com o comportamento do campo magnético dentro do solenóide. Considerando o limite de raio zero para o valor fixo do fl.mm magnético, nós obtemos um hamiltoniano auto-adjunto particular que corresponde à condição de contorno específica para o caso do campo magneto-solenoidal com o solenóide AB. Nós chamamos estes casos particulares das extensões auto-adjuntas extensões naturais. Para completeza da investigação nós estudamos também o comportamento de uma partícula sem spin no campo magneto-solenoidal regularizado. A etapa seguinte da investigação é a construção das funções de Green da equação de Dirac com o campo MS em 2 + 1 e 3 + 1 dimensões. As funções de Green são construídas por meio de um somatório sobre o conjunto completo das soluções da equação de Dirac. Ao construir as funções de Green, nós usamos as soluções exatas da equação de Dirac, que são relacionadas a valores específicos do parâmetro de extensão. Estes valores correspondem às extensões naturais. Depois nós estendemos os resultados ao caso em 3 + 1 dimensões. Nós apresentamos também as funções de Green não relativísticas e as funções de Green de uma partícula relativística escalar.ln the present work the Dirac equation with the supereposition of the Aharonov-Bohm (AB) field and a collinear uniform magnetic field, which we call a magnetic-solenoid (MS) field, is studied. Using von Neumann\'s theory of the self-adjoint extensions of symmetric operators, in 2 + 1 dimensions we construct a one-parameter family of self-adjoint Dirac Hamiltonians specified by boundary conditions at the AB solenoid and find the spectrurn and eigenfunctions for each value of the extension parameter. We reduce the (3 + 1)-dimensional. problem to the (2 + 1)-dimensional one by a proper choice of the spin operator, which allows realizing all the programme of constructing self-adjoint extensions and finding spectra and eigenfunctions in the previous tenns. We also present the reduced self-adjoint extension method for the radial Dirac Hamiltonian with the MS field. We then turn to the regularized case of finite-radius solenoid. We study the structure of the corresponding eigenfunctions and their dependence on the behavior of the magnetic field inside the solenoid. Considering the zero-radius limit with the fixed value of the magnetic flux, we obtain a concrete self-adjoint Hamiltonian corresponding to a specific boundary condition for the case of the magnetic-solenoid field \'W-ith the AB solenoid. These particular cases of self-adjoint extensions we call natural extensions. For completeness we also study the behavior of the spinless particle in the regularized magnetic-solenoid field. Successive step of our investigation is a construction of the Green functions of the Dirac equation with the MS field in 2 + 1 and 3 + 1 dimensions. The Green functions are constructed by means of summation over the complete set of solutions of the Dirac equation. Constructing the Green functions, we use the exact solutions of the Dirac equation that are related to the specific values of the extension parameter. These values correspond to the natural extension. Then we extend the results to the (3 + 1)-dimensional case. For the sake of completeness, we present nonrelativistic Green functions and Green functions of the relativistic scalar particle.
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Ntenhene, Felix. "Risking it to Libya : Irregular Migration from the Brong Ahafo Region of Ghana to Libya." Thesis, Malmö universitet, Institutionen för globala politiska studier (GPS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-44212.
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This thesis explores the phenomenon of irregular migration from the Brong Ahafo region of Ghana to Libya. It draws on migration theories to explain the underlying drivers of the phenomenon in the region. Many studies on irregular migration in Sub-Saharan Africa have predominantly attributed it to the push/pull theory. The objective here is to go beyond this stereotypical way of theorizing irregular migration in Sub-Saharan Africa by drawing on a wide range of migration theories to explain the underlying drivers of irregular migration from the Brong Ahafo region of Ghana to Libya. The evidence suggests that the drivers of irregular migration in the area under study are complex and nested in a broad-spectrum of social, cultural, moral, economic, historical, etc. context. Therefore, a single theory is inadequate to present a comprehensive explanation for the underlying drivers of the subject. It is revealed that there is the emergence of contemporary competing factors such as sports betting and internet fraud with some of the root causes of the phenomenon in the region. Hence, some of the root causes are weakened by these contemporary factors.
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Veyrat, Louis. "Quantum Transport Study in 3D Topological Insulators Nanostructures." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-210217.
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In this thesis, we investigate the quantum transport properties of disordered three dimensional topological insulator (3DTI) nanostructures of BiSe and BiTe in detail. Despite their intrinsic bulk conductivity, we show the possibility to study the specific transport properties of the topological surface states (TSS), either with or without quantum confinement. Importantly, we demonstrate that unusual transport properties not only come from the Dirac nature of the quasi-particles, but also from their spin texture.
Without quantum confinement (wide ribbons), the transport properties of diffusive 2D spin-helical Dirac fermions are investigated. Using high magnetic fields allows us to measure and separate all contributions to charge transport. Band bending is investigated in BiSe nanostructures, revealing an inversion from upward to downward bending when decreasing the bulk doping. This result points out the need to control simultaneously both the bulk and surface residual doping in order to produce bulk-depleted nanostructures and to study TSS only. Moreover, Shubnikov-de-Haas oscillations and transconductance measurements are used to measure the ratio of the transport length to the electronic mean free path ltr/le. This ratio is measured to be close to one for bulk states, whereas it is close to 8 for TSS, which is a hallmark of the anisotropic scattering of spin-helical Dirac fermions.
With transverse quantum confinement (narrow wires or ribbons), the ballistic transport of quasi-1D surface modes is evidenced by mesoscopic transport measurements, and specific properties due to their topological nature are revealed at very low temperatures. The metallic surface states are directly evidenced by the measure of periodic Aharonov-Bohm oscillations (ABO) in 3DTI nanowires. Their exponential temperature dependence gives an unusual power-law temperature dependence of the phase coherence length, which is interpreted in terms of quasi-ballistic transport and decoherence in the weak-coupling regime. This remarkable finding is a consequence of the enhanced transport length, which is comparable to the perimeter. Besides, the ballistic transport of quasi-1D surface modes is further evidenced by the observation of non-universal conductance fluctuations in a BiSe nanowire, despite the long-length limit (L > ltr) and a high metallicity (many modes). We show that such an unusual property for a mesoscopic conductor is related to the limited mixing of the transverse modes by disorder, as confirmed by numerical calculations. Importantly, a model based on the modes' transmissions allows us to describe our experimental results, including the full temperature dependence of the ABO amplitude.