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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Diagonalizable subalgebras of the first Weyl algebra

Tan, Xiaobai Unknown Date
No description available.
2

The Lanczos tensor in spacetime geometry and the canonical formulation of general relativity

Benas, Konstantinos January 2001 (has links)
No description available.
3

Diagonalizable subalgebras of the first Weyl algebra

Tan, Xiaobai. January 2009 (has links)
Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Dec. 10, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Pure Mathematics, Department of Mathematical and Statistical Sciences, University of Alberta." Includes bibliographical references.
4

Weyl group elements associated to conjugacy classes

Chan, Kei-yuen., 陳佳源. January 2010 (has links)
published_or_final_version / Mathematics / Master / Master of Philosophy
5

Soluções exatas da métrica de Weyl para aproximação de segunda ordem de um disco fino e testes clássicos da RG

Valada, Rafael da Silva January 2013 (has links)
Soluções exatas das equações de campo de Einstein sempre foram de muita importância para o desenvolvimento da teoria da relatividade geral, tanto do ponto de vista teórico quanto do observacional. Neste trabalho, estudamos o espaço-tempo de um disco fino através da obtenção de soluções exatas das equações de Einstein para a região exterior de um corpo maciço com simetria cilíndrica. Utilizando a métrica estática de Weyl para descrever este espaço-tempo, buscamos soluções na forma de potência para as funções da expansão de segunda ordem de tal métrica. Nossas soluções foram aplicadas ao problema da precessão do periélio de planetas solares bem como a deflexão da luz, proveniente de objetos distantes, ao passar próxima ao Sol. / The exact solutions of Einstein's eld equations have always been of great importance for the development of the general theory of relativity, from both theoretical and observational point of view. In this dissertation, we study the spacetime of a thin disk by obtaining exact solutions of the Einstein eld equations for the exterior region of a massive body with cylindrical symmetry. Using the static Weyl metric to describe this space-time, we look for power law solutions for the expansion of the second-order-metric functions. Our solutions have been applied to the precession of the perihelion of solar planets, as well as to the de ection of light from distant objects as it passes close to the Sun.
6

Soluções exatas da métrica de Weyl para aproximação de segunda ordem de um disco fino e testes clássicos da RG

Valada, Rafael da Silva January 2013 (has links)
Soluções exatas das equações de campo de Einstein sempre foram de muita importância para o desenvolvimento da teoria da relatividade geral, tanto do ponto de vista teórico quanto do observacional. Neste trabalho, estudamos o espaço-tempo de um disco fino através da obtenção de soluções exatas das equações de Einstein para a região exterior de um corpo maciço com simetria cilíndrica. Utilizando a métrica estática de Weyl para descrever este espaço-tempo, buscamos soluções na forma de potência para as funções da expansão de segunda ordem de tal métrica. Nossas soluções foram aplicadas ao problema da precessão do periélio de planetas solares bem como a deflexão da luz, proveniente de objetos distantes, ao passar próxima ao Sol. / The exact solutions of Einstein's eld equations have always been of great importance for the development of the general theory of relativity, from both theoretical and observational point of view. In this dissertation, we study the spacetime of a thin disk by obtaining exact solutions of the Einstein eld equations for the exterior region of a massive body with cylindrical symmetry. Using the static Weyl metric to describe this space-time, we look for power law solutions for the expansion of the second-order-metric functions. Our solutions have been applied to the precession of the perihelion of solar planets, as well as to the de ection of light from distant objects as it passes close to the Sun.
7

Soluções exatas da métrica de Weyl para aproximação de segunda ordem de um disco fino e testes clássicos da RG

Valada, Rafael da Silva January 2013 (has links)
Soluções exatas das equações de campo de Einstein sempre foram de muita importância para o desenvolvimento da teoria da relatividade geral, tanto do ponto de vista teórico quanto do observacional. Neste trabalho, estudamos o espaço-tempo de um disco fino através da obtenção de soluções exatas das equações de Einstein para a região exterior de um corpo maciço com simetria cilíndrica. Utilizando a métrica estática de Weyl para descrever este espaço-tempo, buscamos soluções na forma de potência para as funções da expansão de segunda ordem de tal métrica. Nossas soluções foram aplicadas ao problema da precessão do periélio de planetas solares bem como a deflexão da luz, proveniente de objetos distantes, ao passar próxima ao Sol. / The exact solutions of Einstein's eld equations have always been of great importance for the development of the general theory of relativity, from both theoretical and observational point of view. In this dissertation, we study the spacetime of a thin disk by obtaining exact solutions of the Einstein eld equations for the exterior region of a massive body with cylindrical symmetry. Using the static Weyl metric to describe this space-time, we look for power law solutions for the expansion of the second-order-metric functions. Our solutions have been applied to the precession of the perihelion of solar planets, as well as to the de ection of light from distant objects as it passes close to the Sun.
8

Spectroscopy of Topological Materials:

Osterhoudt, Gavin Barnes January 2020 (has links)
Thesis advisor: Kenneth S. Burch / Since their first experimental realizations in the 2000s, bulk electronic topological materials have been one of the most actively studied areas of condensed matter physics. Among the more recently discovered classes of topological materials are the Weyl semimetals whose low energy excitations behave like massless, relativistic particles with well-defined chirality. These material systems display exotic behavior such as surface Fermi arc states, and the chiral anomaly in which parallel magnetic and electric fields lead to an imbalance of left- and right-handed particles. Much of the research into these materials has focused on the electronic properties, but relatively little has been directed towards understanding the vibrational properties of these systems, or of the interplay between the electronic and vibrational degrees of freedom. Further, the technological potential of these materials is still underdeveloped, with the search for physical properties enhanced by the topological nature of these materials being sought after. In this dissertation we address both of these issues. In Chapters III and IV we present temperature dependent Raman investigations of the the Weyl semimetals WP2, NbAs, and TaAs. Measurements of the optical phonon linewidths are used to identify the available phonon decay paths, with ab-initio calculations and group theory used to aid the interpretation of these results. We find that some phonons display linewidths indicative of dominant decay into electron-hole pairs near the Fermi surface, rather than decay into acoustic phonons. In light of these results we discuss the role of phonon-electron coupling in the transport properties of these Weyl semimetals. In Chapter V, we discuss the construction of our "PVIC" setup for the measurement of nonlinear photocurrents. We discuss the experimental capabilities that the system was designed to possess, the operating principles behind key components of the system, and give examples of the operating procedures for using the setup. The penultimate chapter, Chapter VI, presents the results of photocurrent measurements using this setup on the Weyl semimetal TaAs. Through careful analysis of the photocurrent polarization dependence, we identify a colossal bulk photovoltaic effect in this material which exceeds the response displayed by previously studied materials by an order of magnitude. Calculations of the second-order optical conductivity tensor show that this result is consistent with the divergent Berry connection of the Weyl nodes in TaAs. In addition to these topics, Chapter II addresses the results of Raman measurements on thin film heterostructures of the topological insulator Bi2Se3 and the magnetic semiconductor EuS. By investigating the paramagnetic Raman signal in films with different compositions of EuS and Bi2Se3 we provide indirect evidence of charge transfer between the two layers. We also track the evolution of phonon energies with varying film thicknesses on multiple substrates which provides insight into the interfacial strain between layers. We conclude the dissertation in Chapter VII with a summary of the main results from each preceding chapter, and give suggestions for future experiments that further investigate these topics. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.
9

Topological Weyl Superconductivity

Chen, Chun-Hao Hank 30 August 2019 (has links)
The topological aspects of superconductivity on doped Weyl semimetals are investigated. / Topological phases of matter have sparked significant experimental and theoretical interest due to the topologically robust edge modes they host, as well as their classification through rich mathematics. An interesting example of a topological phase in three dimensions, the Weyl semimetal, can exhibit topological ordering through the existence of Fermi arcs on the surfaces of the material. For the doped Weyl semimetal, we investigate possible resulting Weyl superconducting states --- both the inter-Fermi surface pairing state following Li and Haldane, and the intra-Fermi surface pairing state following Burkov --- in this thesis, and study their topological properties by computing the gapless Weyl-Majorana edge modes they host. The results obtained in Ref. \cite{LH} for the inter-Fermi surface superconducting state are reproduced, and the bulk and edge properties of the intra-Fermi surface pairing superconducting state are studied in detail. / Thesis / Master of Science (MSc) / In this thesis, we study an interesting class of topological materials called the Weyl semimetal as well as its associated superconducting phases. A description of the Fermi arcs on Weyl semimetals are given, and the topological properties of the inter-Fermi surface and intra-Fermi surface pairing states are studied in detail.
10

Ideais maximais cíclicos à esquerda da álgebra de Weyl A2(K)

Ferreira, Jose Luiz de Oliveira January 2004 (has links)
Neste trabalho, dado um corpo K de característica zero, discutimos a existência de ideais maximais da Álgebra de Weyl An(K) gerados por operadores de ordem 1. Para a Álgebra de Weyl A1(K), apresentamos exemplos de ideais maximais cíclicos; para n maior ou igual a 2, entre especiais operadores de ordem um, nós caracterizamos aqueles que geram ideais maximais. Finalmente, para n = 2, mostramos que, para toda derivação simples da forma d = al + {382, com {3 E K[X1, X2], existe é E {1, -1} tal que A2 · (d + éX2) é um ideal maximal de A2(K) e que este resultado é ótimo, no sentido de que a condição "é E {1, -1}" não pode ser substituída por "é sempre igual a 1" ou por "é sempre igual a -1". / In this work, given a field K of characteristic zero, we present examples of cyclic maximalleft ideais of the vVeyl algebra A1(K) generated by operators of order one; for n maior ou igual a 2, among special operators of order one, we characterize the ones which generate maximalleft ideais. Finally, for n = 2, we show that for every simple derivation of the form d = 81 + {382 with {3 E K (Xll X2] there exists é E {1, - 1} such that A2 · (d + éX2) is a left maximal ideal of A2(K), and that this condition is optimal in the sense that "é= 1" doesn 't work always and "é = -1" doesn 't work always.

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