Дисертації з теми "Topological physics"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Topological physics".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Tapio, O. (Ossi). "Topological defects in cosmology." Master's thesis, University of Oulu, 2013. http://urn.fi/URN:NBN:fi:oulu-201302121030.
Повний текст джерелаMoore, Christopher Paul. "Tunneling Transport Phenomena in Topological Systems." Thesis, Clemson University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13420479.
Повний текст джерелаOriginally proposed in high energy physics as particles, which are their own anti-particles, Majorana fermions have never been observed in experiments. However, possible signatures of their condensed matter analog, zero energy, charge neutral, quasiparticle excitations, known as Majorana zero modes (MZMs), are beginning to emerge in experimental data. The primary method of engineering topological superconductors capable of supporting MZMs is through proximity-coupled semiconductor nanowires with strong Rashba spin-orbit coupling and an applied magnetic field. Recent tunneling transport experiments involving these materials, known as semiconductor-superconductor heterostructures, were capable for the first time of measuring quantized zero bias conductance plateaus, which are robust over a range of control parameters, long believed to be the smoking gun signature of the existence of MZMs. The possibility of observing Majorana zero modes has garnered great excitement within the field due to the fact that MZMs are predicted to obey non-Abelian quantum statistics and therefore are the leading candidates for the creation of qubits, the building blocks of a topological quantum computer. In this work, we first give a brief introduction to Majorana zero modes and topological quantum computing (TQC). We emphasize the importance that having a true topologically protected state, which is not dependent on local degrees of freedom, has with regard to non-Abelian braiding calculations. We then introduce the concept of partially separated Andreev bound states (ps-ABSs) as zero energy states whose constituent Majorana bound states (MBSs) are spatially separated on the order of the Majorana decay length. Next, through numerical calculation, we show that the robust 2 e2/h zero bias conductance plateaus recently measured and claimed by many in the community to be evidence of having observed MZMs for the first time, can be identically created due to the existence of ps-ABSs. We use these results to claim that all localized tunneling experiments, which have been until now the main way researchers have tried to measure MZMs, have ceased to be useful. Finally, we outline a two-terminal tunneling experiment, which we believe to be relatively straight forward to implement and fully capable of distinguishing between ps-ABSs and true topologically protected MZMs.
Timothy, H. Hsieh Timothy (Timothy Hwa-wei). "Topological materials and quantum entanglement." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/103228.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 83-91).
As the title implies, this thesis consists of two main topics: materials which realize topological phases of matter and applications of the concept of entanglement in understanding topological phases and their transitions. The first part will focus on a particular class of materials called topological crystalline insulators (TCI), which are bulk insulators with metallic boundary states protected by crystal mirror symmetries. The realization of TCIs in the SnTe class of materials and the anti-perovskite family will be described. The second part will focus on using entanglement notions to probe a topological phase transition, based on a single topological wavefunction. This is achieved by performing extensive partitions of the wavefunction, such as a checkerboard partition. Implementing this technique in one dimension naturally involves the use of tensor networks, which will be reviewed and then utilized.
by Timothy H. Hsieh.
Ph. D.
Chess, Jordan J. "Mapping Topological Magnetization and Magnetic Skyrmions." Thesis, University of Oregon, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10684160.
Повний текст джерелаA 2014 study by the US Department of Energy conducted at Lawrence Berkeley National Laboratory estimated that U.S. data centers consumed 70 billion kWh of electricity. This represents about 1.8% of the total U.S. electricity consumption. Putting this in perspective 70 billion kWh of electricity is the equivalent of roughly 8 big nuclear reactors, or around double the nation's solar panel output. Developing new memory technologies capable of reducing this power consumption would be greatly beneficial as our demand for connectivity increases in the future. One newly emerging candidate for an information carrier in low power memory devices is the magnetic skyrmion. This magnetic texture is characterized by its specific non-trivial topology, giving it particle-like characteristics. Recent experimental work has shown that these skyrmions can be stabilized at room temperature and moved with extremely low electrical current densities. This rapidly developing field requires new measurement techniques capable of determining the topology of these textures at greater speed than previous approaches. In this dissertation, I give a brief introduction to the magnetic structures found in Fe/Gd multilayered systems. I then present newly developed techniques that streamline the analysis of Lorentz Transmission Electron Microscopy (LTEM) data. These techniques are then applied to further the understanding of the magnetic properties of these Fe/Gd based multilayered systems.
This dissertation includes previously published and unpublished co-authored material.
Damodaran, K. "Topological defects in cosmology and nuclear physics." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598261.
Повний текст джерелаYang, Biao. "Photonic topological metamaterials." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8103/.
Повний текст джерелаLu, Fuyan. "Topological Phases with Crystalline Symmetries." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524790822570583.
Повний текст джерелаLifschytz, Gilad. "Quantum gravity and topological field theory." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/33529.
Повний текст джерелаTang, Evelyn (Evelyn May Yin). "Topological phases in narrow-band systems." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/103220.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 64-72).
I discuss several novel topological phases in correlated electron systems, realized through spin-orbit interactions and lattice effects especially narrow-band systems. The first realizes the fractional quantum Hall effect using geometric frustration and ferromagnetism to obtain a nearly flat band with a large bandgap and non-zero Chern number. This system can support this effect at high temperatures upon partial filling of the flat band. The second proposal builds upon this system: as the ground state is a fractional quantum Hall state, excitations of this state are anyons when there is an incommensurate filling. The underlying lattice allows access to a new regime in which the anyon gas can form a charged superfluid, including states with intrinsic topological order or that similar to a BCS-type state. The third proposal studies topological crystalline insulators and strain as an effective gauge field on the surface state Dirac fermions. The zero-energy Landau orbitals form a flat band where the high density of states gives rise to the interface superconductivity observed in IV-VI semiconductor multilayers at high temperatures, with non-BCS behavior. A discussion of superconductivity in flat band systems concludes and is contrasted with classic results for a typical electron gas. This work closely parallels that in references [1, 2, 3].
by Evelyn Tang.
Ph. D.
Wu, Hao. "Excitations in Topological Superfluids and Superconductors." Thesis, Northwestern University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10259423.
Повний текст джерелаIn this thesis I present the theoretical work on Fermionic surface states, and %the bulk Bosonic collective excitations in topological superfluids and superconductors. Broken symmetries %Bulk-edge correspondence in topological condensed matter systems have implications for the spectrum of Fermionic excitations confined on surfaces or topological defects. (Abstract shortened by ProQuest.)
Wray, Andrew M. "Topological defects and black holes." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332341.
Повний текст джерелаMichieletto, Davide. "Topological interactions in ring polymers." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/77355/.
Повний текст джерелаFarrell, Aaron. "Topological superconductivity without proximity effect." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119741.
Повний текст джерелаRécemment, une région d'intérêt en la recherché de la matière condensée est le recherche pour les "Majorana Fermions". Les physiciens sont fascinés avec cette particule pour des raisons fondamentales et pratiques. Fondamentalement, une particule se comporte comme un Majorana Fermion n'a jamais été trouvée avant. Pratiquement, un Majorana Fermion pourrait être utilisé pour la construction d'un ordinateur quantique. Dans les dernières années, les chercheurs ont commencé à chercher pour des Majorana Fermions dans les supraconducteurs. En particulier, les supraconducteurs topologiques sont crus de supportes les Majorana Fermions dans leur vortex cores et de ce fait des nombreux dispositifs supraconducteurs topologiques ont été proposées. Les propositions récemment sont basées sur les hétérostructures de trois ou deux couches. Dans ces hétérostructures, les bandes d'un semiconducteur avec le couplage de spin-orbit sont séparées par le champ Zeeman d'une couche ferromagnétique (ou un champ appliqué). Après cette, supraconductivité topologique est établie dans la couche de semiconductrice en raison de la proximité d'une couche de supraconducteur ordinaire. Dans cette thèse nous proposons une simplification des dispositifs décrits ci-dessus; nous suggérons un moyen d'enlever la couche de supraconductivité. Nous commençons par proposer un Hamiltonian du cette système et procède à développer des nombreuses méthodes pour analyser cette Hamiltonian avec l'objectif ultime de classifier la topologie de ce système.
Zhong, Shudan. "Linear and Nonlinear Electromagnetic Responses in Topological Semimetals." Thesis, University of California, Berkeley, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13421373.
Повний текст джерелаThe topological consequences of time reversal symmetry breaking in two dimensional electronic systems have been a focus of interest since the discovery of the quantum Hall effects. Similarly interesting phenomena arise from breaking inversion symmetry in three dimensional systems. For example, in Dirac and Weyl semimetals the inversion symmetry breaking allows for non-trivial topological states that contain symmetry-protected pairs of chiral gapless fermions. This thesis presents our work on the linear and nonlinear electromagnetic responses in topological semimetals using both a semiclassical Boltzmann equation approach and a full quantum mechanical approach. In the linear response, we find a ``gyrotropic magnetic effect" (GME) where the current density $j
B$ in a clean metal is induced by a slowly-varying magnetic field. It is shown that the experimental implications and microscopic origin of GME are both very different from the chiral magnetic effect (CME). We develop a systematic way to study general nonlinear electromagnetic responses in the low-frequency limit using a Floquet approach and we use it to study the circular photogalvanic effect (CPGE) and second-harmonic generation (SHG). Moreover, we derive a semiclassical formula for magnetoresistance in the weak field regime, which includes both the Berry curvature and the orbital magnetic moment. Our semiclassical result may explain the recent experimental observations on topological semimetals. In the end, we present our work on the Hall conductivity of insulators in a static inhomogeneous electric field and we discuss its relation to Hall viscosity.
Li, Cheng. "Engineering High Dimensional Topological Matters in Quantum Gases." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1585827770946136.
Повний текст джерелаPugh, David John Rhydwyn. "Topological structures in lattice gauge theory." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279896.
Повний текст джерелаClarke, David A. "Scale Setting and Topological Observables in Pure SU(2) LGT." Thesis, The Florida State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10935396.
Повний текст джерелаIn this dissertation, we investigate the approach of pure SU(2) lattice gauge theory to its continuum limit using the deconfinement temperature, six gradient scales, and six cooling scales. We find that cooling scales exhibit similarly good scaling behavior as gradient scales, while being computationally more efficient. In addition, we estimate systematic error in continuum limit extrapolations of scale ratios by comparing standard scaling to asymptotic scaling. Finally we study topological observables in pure SU(2) using cooling to smooth the gauge fields, and investigate the sensitivity of cooling scales to topological charge. We find that large numbers of cooling sweeps lead to metastable charge sectors, without destroying physical instantons, provided the lattice spacing is fine enough and the volume is large enough. Continuum limit estimates of the topological susceptibility are obtained, of which we favor χ1/4/Tc = 0.643(12). Differences between cooling scales in different topological sectors turn out to be too small to be detectable within our statistical error.
Fatemi, Valla. "Quantum electronic transport in atomically layered topological insulators." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115683.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 153-180).
The merger of topology and symmetry established a new foundation for understanding the physics of condensed matter, beginning with the notion of topological insulators (TIs) for electronic systems. For the time-reversal invariant TIs, a key aspect is the "helical" mode at the boundary of the system - that is, the ID edge of a 2D topological insulator or the 2D surface of a 3D topological insulator. These helical modes represent the extreme limit of spin-orbit coupling in that the spin-degenercy has been completely lifted while preserving time-reversal symmetry. This property is crucial for proposals realizing exotic excitations like the Majorana bound state. In this thesis, I present a series of experiments investigating electronic transport through the boundary modes of 3D and 2D topological insulators, specifically Bi1.5 Sb0.5 Te1.7 Se1.3 and monolayer WTe 2 , respectively. For the case of ultra-thin WTe 2 , I also present experiments detailing investigations of the 2D bulk states, finding a semimetallic state for the trilayer and a superconducting phase for the monolayer, both of which are strongly tunable by the electric field effect. The discovery of 2D topological insulator and 2D superconductor phases within the same material, accessible by standard solid state elecrostatic gates, places WTe2 in a unique situation among both TIs and superconductors, potentially enabling gate-configurable topological devices within a homogenous material platform.
by Valla Fatemi.
Ph. D.
Barkeshli, Maissam. "Topological order in the fractional quantum Hall states." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/68964.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 231-237).
This thesis is focused on the theoretical characterization of topological order in non-Abelian fractional quantum Hall (FQH) states. The first part of the thesis is concerned with the ideal wave function approach to FQH states, where the idea is to try to obtain model wave functions and model Hamiltonians for all possible FQH states and to have a physical way of characterizing their topological order. I will explain recent attempts to do this through the so-called pattern of zeros framework and its relation to conformal field theory. The first chapter about the pattern of zeros introduces the basic concepts for single-component FQH states, how it relates to the conformal field theory approach to FQH wave functions, and how it can be used to derive various topological properties of FQH states. The second chapter extends the pattern of zeros framework to multi-component non-Abelian FQH states; this is an attempt at a full classification of possible topological orders in FQH states. Aside from the ideal wave function methods. the other known general method of constructing non-Abelian FQH states is through the parton construction. Here the idea is to break apart the electron into other fermions, called partons. and assume that they form integer quantum Hall states. This method allows us to describe all known FQH states. After reviewing the parton construction, I will demonstrate how it can be used to derive the low energy effective field theories for some of the most well-known non-Abelian FQH states, the Zk parafermion (Laughlin/Moore-Read/Read-Rezayi) states. The parton construction will motivate yet another topological field theory, the U(1) x U(1) x Z2 Chern-Simons (CS) theory. I will demonstrate how to calculate many highly non-trivial topological properties of the U(1) x U(1) x Z2 CS theory, such as ground state degeneracy on genus g surfaces and various fusion properties of the quasiparticles. Using the U(1) x U(1) x Z2 CS theory, we will study phase transitions between bilayer Abelian states and non-Abelian states. The non-Abelian ones contain a series of new states, which we call the orbifold FQH states. These orbifold FQH states turn out to be important for the conceptual foundations of the pattern of zeros/vertex algebra approach to ideal FQH wave functions. We also find a series of non-Abelian topological phases - which are not FQH states and do not have protected gapless edge modes - that are separated from the deconfined phase of ZN gauge theories by a continuous phase transition. We give a preliminary analysis of these Z2 "twisted" ZN topological phases.
by Maissam Barkeshli.
Ph.D.
Valentini, Stefano. "Transport properties in multi-terminal topological superconductors." Doctoral thesis, Scuola Normale Superiore, 2017. http://hdl.handle.net/11384/85902.
Повний текст джерелаIgram, Dale J. "A Topological Explanation of the Urbach Tail." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1459885929.
Повний текст джерелаBleu, Olivier. "Physics of quantum fluids in two-dimensional topological systems." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC044/document.
Повний текст джерелаThis thesis is dedicated to the description of both single-particle and bosonic quantum fluid Physics in topological systems. After introductory chapters on these subjects, I first discuss single-particle topological phenomena in honeycomb lattices. This allows to compare two theoretical models leading to quantum anomalous Hall effect for electrons and photons and to discuss the photonic quantum valley Hall effect at the interface between opposite staggered cavity lattices.In a second part, I present some phenomena which emerge due to the interplay of the linear topological effects with the presence of interacting bosonic quantum fluid described by mean-field Gross-Pitaevskii equation. First, I show that the spin-anisotropic interactions lead to density-driven topological transitions for elementary excitations of a condensate loaded in the polariton quantum anomalous Hall model (thermal equilibrium and out-of-equilibrium quasi-resonant excitation configurations). Then, I show that the vortex excitations of a scalar condensate in a quantum valley Hall system, contrary to linear wavepackets, can exhibit a robust chiral propagation along the interface, with direction given by their winding in real space, leading to an analog of quantum spin Hall effect for these non-linear excitations. Finally, coming back to linear geometrical effects, I will focus on the anomalous Hall effect exhibited by an accelerated wavepacket in a two-band system. In this context, I present a non-adiabatic correction to the known semiclassical equations of motion which can be expressed in terms of the quantum geometric tensor elements. We also propose a protocol to directly measure the tensor components in radiative photonic systems
Nemytov, Vadim. "Topological insulators: theory and electronic transport calculations." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114415.
Повний текст джерелаDans cette thèse, nous étudions le transport quantique dans l'isolant topologique (TI) Bi2Se3 à partir d'un modèle d'échelle atomique. Un TI est un matériau ayant une structure de bande de type isolant bien qu'on y retrouve des états hélicodaux en surface. Ces états hélicoı̈daux ont une relation de dispersion linéaire, dite dispersion de Dirac, qui traverse la bande interdite du cristal. Ces électrons voyageant selon les relations de Dirac sont contraints à se mouvoir perpendiculairement à leur spin. La structure électronique particulière de l'isolant topologique Bi2Se3 est due à une forte interaction spin-orbite et est protégée par une symétrie par renversement du temps. Cette thse comporte deux grands segments. Dans un premier temps, nous présentons une synthèse de la théorie générale des isolants topologiques. Nous présentons ensuite les résultats de nossimulation de transport quantique dans le matériau Bi2Se3. Dans notre résumé de la théorie des TI, nous présentons une revue de littérature et décrivons conceptuellement, dans la mesure du possible, le comportement des TI de sorte à rendre notre texte intelligible au non-expert. La théorie des TI est expliquée à artir de phénomènes classiques et quantiques connus tels que l'effet Hall, l'interaction spin-orbite, le courant de spin, l'effet Hall de spin, etc. Le concept de la phase de Berry est ensuite introduit pour faire le pont avec la classification traditionnelle des TI, laquelle se base sur les invariants topologiques de Z2. Le tout est présenté avec la théorie des bandes en filigrane. Dans le second segment de cette thése, nous étudions les propriétés physiques du Bi2Se3 à partir de simulations numériques. Après une brève discussion de certains éléments pertinents empruntés de la théorie du transport quantique et du modèle des liens étroits d'échelle atomique, nous présentons les résultats d'une simulation dans laquelle des électrons voyagent à travers un film de Bi2Se3 ayant une dépression en son milieu. Un tel défaut provoquerait une forte diffusion des porteurs de charge dans un conducteur standard. Dans le cas qui nous concerne, la diffusion des états hélicoı̈daux est endiguée par la contrainte qui force ces états à voyager perpendiculairement à leur spin. Néanmoins, de larges dépressions dans le film peuvent provoquer le mélange des états hélicoı̈daux de surface et des états localisés à l'intérieur du cristal, ce qui affecte le transport des porteurs de charge.
Cooper, Leith. "The topological membrane approach to string theory." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390412.
Повний текст джерелаHigginbotham, Andrew Patrick. "Quantum Dots for Conventional and Topological Qubits." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:23845477.
Повний текст джерелаPhysics
Hart, Sean. "Electronic Phenomena in Two-Dimensional Topological Insulators." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493567.
Повний текст джерелаPhysics
Teh, Nicholas Joshua Yii Wye. "On topological objects in field theory." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610763.
Повний текст джерелаLiu, Jimmy Fangzhou. "Many-body entanglement : topological orders, tensor networks and superconductivity." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99299.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 147-152).
In this thesis, we discuss the characterization and application of quantum many-body entanglements. We try to establish a non-local "order parameter" description of different patterns of many-body entanglement, which are also named topological orders. In 2+ 1D, we show that this could be achieved by calculating the non-Abelian geometric phase (S, T)-matrices from the fixed-point wave functions, obtained in the string-net approach by Levin and Wen and the local unitary transformation approach by Chen, Gu and Wen. In doing so, (S, T)-matrices act as our non-local "order parameter" and give a full characterization of 2+ 1D exact topological orders (topological orders that have a gappable edge). For a generic non-fixed-point wave function, however, obtaining the (S, T)-matrices is numerically formidable. To go around this problem, we introduce a new tensor-network method that works on any generic wave function, and obtain the "environment matrix" as a less powerful "order parameter" description. The "environment matrix" can characterize topological orders described by any gauge theory as well as ID symmetry protected topological (SPT) orders. As an application of both the concept of many-body entanglement and the new tensor-network method developed earlier, in the last chapter of the thesis, we propose a non-BCS mechanism for superconductivity, in which the driving force is not traditional pair-attraction, but statistical confusion of charge carrier induced by strong many-body entanglement. This may open new doors for identifying and constructing new superconducting states.
by Jimmy Fangzhou Liu.
Ph. D.
Demers, Jean-Guy. "Aspects of theories with dynamical, topological or gauge symmetries." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/28058.
Повний текст джерелаStarodubtsev, Artem. "Topological methods in quantum gravity." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1217.
Повний текст джерелаDos, Santos Luiz Henrique Bravo. "Topological Properties of Interacting Fermionic Systems." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10195.
Повний текст джерелаPhysics
Ellis, K. V. "TRAPS : Topological Reconstruction Algorithm for Parton Scatters." Thesis, Queen Mary, University of London, 2012. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8556.
Повний текст джерелаPagano, Michael. "21 cm cosmology of topological defects." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110543.
Повний текст джерелаLes défauts topologiques sont des configurations linéaires d'énergie concentrée produites par certaines brisures de symétries en théorie des champs. Aussi fût-il montré qu'ils sont une conséquence de plusieurs modèles de supergravité. Ces défauts topologiques, formés très tôt dans l'évolution de l'univers, créent d'importantes quantités d'accrétion et produisent une grande quantité de surdensité de baryons. Les surdensités de baryons d'hydrogène génèrent une signature unique de 21cm. Nous focussons sur deux défauts topologique particuliers soit le monopole global et la corde cosmique bouclée et calculons la signature à 21cm produite par chacunes de ces structures. Nous montrons que les deux défauts topologique ci-haut produisent une région elliptique dans la carte de radiation à 21cm avec un grand signal d'émission qui pourrait éventuellement servir comme prédiction pour le future relevé du décalage vers le rouge à 21cm.
Pan, Yue. "Topological Origin of the Urbach Tail." Ohio University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1235514573.
Повний текст джерелаChiel, Joshua R. "Natural Mechanical Topological Insulators." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1586315731890489.
Повний текст джерелаMuhamed, Abera Ayalew. "Moduli spaces of topological solitons." Thesis, University of Kent, 2015. https://kar.kent.ac.uk/47961/.
Повний текст джерелаArcher, Francis John. "A simplicial approach to topological quantum field theory." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260593.
Повний текст джерелаLevin, Michael Aaron Ph D. Massachusetts Institute of Technology. "String-net condensation and topological phases in quantum spin systems." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36810.
Повний текст джерелаIncludes bibliographical references (p. 81-86).
For many years, it was thought that Landau's theory of symmetry breaking could describe essentially all phases and phase transitions. However, in the last twenty years, it has become clear that at zero temperature, quantum mechanics allows for the possibility of new phases of matter beyond the Landau paradigm. In this thesis, we develop a general theoretical framework for these "exotic phases" analogous to Landau's framework for symmetry breaking phases. We focus on a particular type of exotic phase, known as "topological phases", and a particular physical realization of topological phases - namely frustrated quantum magnets. Our approach is based on a new physical picture for topological phases. We argue that, just as symmetry breaking phases originate from the condensation of particles, topological phases originate from the condensation of extended objects called "string-nets." Using this picture we show that, just as symmetry breaking phases can be classified using symmetry groups, topological phases can be classified using objects known as "tensor categories."
(cont.) In addition, just as symmetry breaking order manifests itself in local correlations in a ground state wave function, topological order manifests itself in nonlocal correlations or quantum entanglement. We introduce a new quantity - called "topological entropy" - which measures precisely this nonlocal entanglement. Many of our results are applicable to other (non-topological) exotic phases.
by Michael Aaron Levin.
Ph.D.
Lue, Arthur. "Topological structure in classical and quantum SU(2)-Higgs theories." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10373.
Повний текст джерелаRauch, Marco [Verfasser]. "Topological string theory, modularity and non-perturbative physics / Marco Rauch." Bonn : Universitäts- und Landesbibliothek Bonn, 2011. http://d-nb.info/1016219601/34.
Повний текст джерелаJaubert, Ludovic D. C. "Topological Constraints and Defects in Spin Ice." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2009. http://tel.archives-ouvertes.fr/tel-00462970.
Повний текст джерелаRonquillo, David C. "Identifying topological order in the Shastry-Sutherland model via entanglement entropy." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1596474.
Повний текст джерелаIt is known that for a topologically ordered state the area law for the entanglement entropy shows a negative universal additive constant contribution, –γ, called the topological entanglement entropy. We theoretically study the entanglement entropy of the two-dimensional Shastry-Sutherland quantum antiferromagnet using exact diagonalization on clusters of 16 and 24 spins. By utilizing the Kitaev-Preskill construction, we extract a finite topological term, –γ , in the region of bond-strength parameter space corresponding to high geometrical frustration. Thus, we provide strong evidence for the existence of an exotic topologically ordered state and shed light on the nature of this model's strongly frustrated, and long controversial, intermediate phase.
Cacciuto, Angelo. "Statistical mechanics of self-avoiding crystalline membranes and topological defect formation." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2002. http://wwwlib.umi.com/cr/syr/main.
Повний текст джерелаWolf, Michael Scott. "Infrared and Optical Studies of Topological Insulators BI2TE3 BI2SE3 and SB2TE3." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1310675743.
Повний текст джерелаChow, Chee-Seng. "Phoenix : an interactive hierarchical topological floorplanning placer." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/77677.
Повний текст джерелаBibliography: leaf 141.
by Chee-Seng Chow.
M.S.
B.S.
Brell, Courtney Gordon Gray. "Many-body models for topological quantum information." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/13539.
Повний текст джерелаHagan, Scott. "Scale invariant and topological approaches to the cosmological constant problem." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39926.
Повний текст джерелаMotivated by the natural connection between dilatation invariance and the extinction of the vacuum energy density, a phenomenological realization of a global scale symmetry is constructed. A complete treatment of such a realization in the context of a supergravitational toy model is calculated to one loop using an effective potential formalism. Particular attention is paid to the quantization of both supersymmetric and general coordinate gauges and to the concomitant ghost structure since traditional treatments have introduced non-local operators in the ghost Lagrangian and generating functional. Contributions to the effective potentid from the gravity sector are thus determined that contradict the literature. A particular class of tree-level scalar potentials that includes the 'no-scale' case is studied in the that space limit. While it is found that scale invariance can be maintained at the one-loop level and the cosmological constant made to vanish for all potentials in the class this is directly attributable to supersymmetry. A richer form of the Kahler potential or an enlarged particle content may facilitate the breaking of supersymmetry.
Phenomenological consequences of supergravity are investigated through a one-loop calculation of the electromagnetic form factor of the gravitino. Should such a form factor exist a signature of the gravitino might be found in processes with unlabeled products such as $e sp+e sp- to nothing.$ It is found that the form factor vanishes to this order, the Lorentz structures generated being too impoverished to withstand a constraining set of polarization conditions.
Finally the wormhole solution to the cosmological constant problem is examined in a semiclassical approximation. The notion that scalar field worm-holes must have associated conserved charges is questioned and a model of massive scalar field wormholes is delineated and proven to provide a counterexample. As the model allows baby universes nucleated with a certain eigenvalue of the scalar field momentum to classically evolve to a different value, competing semiclassical paths contribute to the same transition amplitude. Numerical simulations demonstrate that the novel semiclassical paths available to massive solutions cannot be overlooked in approximating the tunneling amplitude.
Nikolic, Aleksandar. "The physics of multilayer topological insulator heterostructures using low-energy models." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283001.
Повний текст джерелаLo, Wei-Chang. "Ring polymers as topological glass, a new phase of matter?" Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/46819/.
Повний текст джерелаLatief, Andy Octavian. "Tunnelling density of states studies of the topological Kondo effect." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8475/.
Повний текст джерела