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Modelo de redes de inovação para uma metodologia de gestão: implementações de teoria das restrições; Model of innovation networks for a management methodology: theory of constraints implementations

Calia, Rogério Cerávolo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 21/06/2005 PT
Relevância na Pesquisa
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A pesquisa tem como objetivo propor um modelo para a formação e gerenciamento de redes de inovação em uma metodologia de gestão: a teoria das restrições aplicada ao planejamento e controle de produção. Como objetivo secundário, a pesquisa visa propor uma ferramenta prática para se gerenciar a transferência de know-how de teoria das restrições para as manufaturas usuárias. Tais propostas se fundamentam tanto na teoria de inovação, na teoria de redes e na teoria de redes de inovação, como em três estudos de caso de implementações de teoria das restrições. Na perspectiva das manufaturas usuárias, a implementação de teoria das restrições representa uma inovação para diminuir atrasos de entrega e para diminuir estoques. Tais benefícios são tanto mais rápidos, quanto mais veloz for o processo de transferência do know-how de teoria das restrições ao time responsável pelo planejamento e controle da produção. Com a finalidade de se contribuir para o aumento da eficiência na capacitação em teoria das restrições, propõe-se uma ferramenta gerencial prática denominada mapeamento do fluxo de transferência de know-how de teoria das restrições. Já na perspectiva dos especialistas em implementações de teoria das restrições...

Rumo à 'metapsicologia dos limites': o diálogo possível entre a teoria pulsional e a teoria das relações de objeto e algumas de suas consequências - Freud, Winnicott e Green; Towards metapsychology of limits: the possible dialogue between drive theory and object relational theory and some of its consequences Freud, Winnicott and Green

Junqueira, Camila
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/03/2010 PT
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Este trabalho fundamenta-se na compreensão da metapsicologia dos limites como parte da teoria psicanalítica que visa compreender a estruturação e o funcionamento dos limites do psiquismo, bem como parte da teoria psicanalítica que se destina a compreender a etiologia, o funcionamento e o tratamento das patologias-limite, manifestações decorrentes de falhas na constituição e no funcionamento dos limites do psiquismo. Tem como hipótese de pesquisa que o giro metapsicológico exigido pelos estados-limite se coloca menos no sentido de ampliar a diversidade de modelos teóricos e mais no sentido de fazer dialogar dois modelos teóricos que estão na base do pensamento psicanalítico, mas que foram historicamente separados e considerados incompatíveis, a saber: o modelo pulsional e o modelo das relações objetais. Os objetivos deste trabalho são os de (1) questionar os limites da oposição entre a teoria pulsional de Freud e a teoria relacional de Winnicott, (2) apresentar a alternativa que André Green propõe para essa aparente oposição, argumentando a favor da concepção de pulsão e objeto como um par inseparável, bem como (3) apresentar e discutir algumas consequências metapsicológicas do diálogo possível entre essas duas teorias a partir do estudo de Freud e de Winnicott...

Conformal Invariance and Liouville Field Theory; Invariância Conforme e Teoria de Campo de Liouville

Díaz, Laura Raquel Rado
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/06/2015 EN
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In this work, we make a brief review of the Conformal Field Theory in two dimensions,in order to understand some basic definitions in the study of the Liouville Field Theory, which has many application in theoretical physics like string theory, general relativity and supersymmetric gauge field theories. In particular, we focus on the analytic continuation of the Liouville Field Theory, context in which an interesting relation with the Chern-Simons Theory arises as an extension of its well-known relation with the Wess-Zumino-Witten model. Thus, calculating correlation functions by using the complex solutions of the Liouville Theory will be crucial aim in this work in order to test the consistency of this analytic continuation. We will consider as an application the time-like version of the Liouville Theory, which has several applications in holographic quantum cosmology and in studying tachyon condensates. Finally, we calculate the three-point function for the Wess-Zumino-Witten model for the standard Kac-Moody level k > 2 and the particular case 0 < k < 2, the latter has an interpretation in time-dependent scenarios for string theory. Here we will find an analogue relation we find by comparing the correlation function of the time-like and space-like Liouville Field Theory.; Neste trabalho...

Theory-oriented software engineering

Stol, Klaas-Jan; Fitzgerald, Brian
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
ENG
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peer-reviewed; There has been a growing interest in the role of theory within Software Engineering (SE) research. For several decades, researchers within the SE research community have argued that, to become a ‘real’ engineering science, SE needs to develop stronger theoretical foundations. However, so far, the role of theory is neither fully appreciated nor well understood in SE research. Without a good common understanding of what theory is, what it constitutes in SE research, and the various roles it can play in SE research, it is di cult to appreciate how theory building can help to strengthen SE research. In this paper we discuss the importance of theory and conceptualization, and review the key components that comprise a theory. We then present the Research Path Schema (RPS), which is an adaptation of an analytical framework from the social sciences. The RPS defines a research study as consisting of three components: some phenomenon, system or substance that a researcher is interested in; some technique or method to study that substance; and some form of conceptualization or theory that provides an explanation for, or abstraction of the observations made in a study. Di erent research studies have a di erent archetypical ‘architecture...

Civil-military relations and concordance theory : a case study of Argentina

Anderson, John M.
Fonte: Monterey, California: Naval Postgraduate School Publicador: Monterey, California: Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xii, 81 p.;28 cm.
EN_US
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Approved for public release; distribution is unlimited.; The purpose of this thesis is to test Rebecca L. Schiff's "Theory of Concordance" against the case of Argentina. Using the case study method to determine whether this relatively neglected theory of civil-military relations accounts for the occurrence of military interventions in Argentina, this thesis also examines whether the theory provides a better tool than separation theory by which to analyze civil-military relations in Latin America. Separation theory describes the separation of civil and military institutions as it occurs in the United States and suggests that it is the ideal model for other nations to emulate. Concordance theory argues that three partner the military, the political elites, and the citizenry should aim for a cooperative relationship that may or may not involve separation, but does not require it. What is interesting about this theory is that it accounts for the U.S. model as well. The thesis concludes that in the case of Argentina, separation theory better predicts the mechanisms by which a civilian government may establish control over its formerly interventionist military. However, with modification, concordance theory may provide insights into how that control may be maintained following the transition to enduring democracy.; Major...

Optimising professional life: a grounded theory of doctors' careers

Piko, Lesley Margaret
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD)
EN
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This thesis presents the Theory of Optimising Professional Life - a new career theory derived from the professional lives of experienced general practitioners (GPs) working in Australia. GP careers involve a portfolio of clinical and non-clinical roles and are most often forged in small, non-hierarchical, private business organisations. This career structure does not conform to the traditional notion of a linear upward progression that underpins many career theories. Furthermore, existing career theories do not reflect the Australian medical context, including the concerns, needs and behaviours of doctors working in Australia. The Theory of Optimising Professional Life was discovered using Glaser’s grounded theory method and a quantitative analysis of survey responses collected for the ‘Medicine in Australia: Balancing Employment and Life (MABEL)’ study. The Theory is compared and contrasted with Dawis and Lofquist’s Theory of Work Adjustment, Super’s career development theory, Patton and McMahon’s Systems Theory Framework and Arthur’s boundaryless career. This thesis found that the main concern GPs have when shaping their professional lives is sustainment - a concept encompassing the aspirational nature of GP career development while also recognising the need for self-care and financial reward. Dynamic tension exists among the three elements of sustainment: the need for self-care to sustain well-being...

A Role For Ideal Theory In Light of The Theory of Second Best

Turnbull, Scott
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
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Political theorists, in increasing frequency, have focused on the application of theories of justice to concrete social issues and policy prescriptions. This so called “policy turn” has made it ever more important to reflect upon the goal of political theory. At the heart of this debate is a concern for action-guidance and a dissatisfaction with what political philosophy has offered in terms of practical relevance. The ideal guidance approach to ideal theory, best exemplified by John Rawls, holds a complementary relation between ideal and non-ideal theory, in which the former provides the goal for the latter to approximate. This approach to ideal theory, however, has been challenged by the Theory of the Second Best which undermines the assumption that simply approximating an ideal will result in the second best available option. Despite this challenge from the TOSB it will be the project of this paper to defend a more indirect role for ideal theory in political theorizing. My thesis is organized as follows. Chapter 2 will introduce the concept of ideal theory and fact sensitivity and provide a brief overview of how philosophers have attempted to define these concepts. I will argue that it is important to distinguish the ideal guidance approach from more epistemological approaches to theorizing about justice. In chapter 3...

Yang-Mills Theory as a Deformation of Topological Field Theory, Dimensional Reduction and Quark Confinement

Kondo, Kei-Ichi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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We propose a reformulation of Yang-Mills theory as a perturbative deformation of a novel topological (quantum) field theory. We prove that this reformulation of the four-dimensional QCD leads to quark confinement in the sense of area law of the Wilson loop. First, Yang-Mills theory with a non-Abelian gauge group G is reformulated as a deformation of a novel topological field theory. Next, a special class of topological field theories is defined by both BRST and anti-BRST exact action corresponding to the maximal Abelian gauge leaving the maximal torus group H of G invariant. Then we find the topological field theory ($D>2$) has a hidden supersymmetry for a choice of maximal Abelian gauge. As a result, the D-dimensional topological field theory is equivalent to the (D-2)-dimensional coset G/H non-linear sigma model in the sense of Parisi and Sourlas dimensional reduction. After maximal Abelian gauge fixing, the topological property of magnetic monopole and anti-monopole of four-dimensional Yang-Mills theory is translated into that of instanton and anti-instanton in two-dimensional equivalent model. It is shown that the linear static potential in four-dimensions follows from the instanton--anti-instanton gas in the equivalent two-dimensional non-linear sigma model obtained from the four-dimensional topological field theory by dimensional reduction...

K-Theory, D-Branes and Ramond-Ramond Fields

Valentino, Alessandro
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/12/2008
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This thesis is dedicated to the study of K-theoretical properties of D-branes and Ramond-Ramond fields. We construct abelian groups which define a homology theory on the category of CW-complexes, and prove that this homology theory is equivalent to the bordism representation of KO-homology, the dual theory to KO-theory. We construct an isomorphism between our geometric representation and the analytic representation of KO-homology, which induces a natural equivalence of homology functors. We apply this framework to describe mathematical properties of D-branes in type I String theory. We investigate the gauge theory of Ramond-Ramond fields arising from type II String theory defined on global orbifolds. We use the machinery of Bredon cohomology and the equivariant Chern character to construct abelian groups which generalize the properties of differential K-theory defined by Hopkins and Singer to the equivariant setting, and can be considered as a differential extension of equivariant K-theory for finite groups. We show that the Dirac quantization condition for Ramond-Ramond fieldstrengths on a good orbifold is dictated by equivariant K-theory and the equivariant Chern character, and study the group of flat Ramond-Ramond fields in the particular case of linear orbifolds in terms of our orbifold differential K-theory.; Comment: Ph.D. Thesis...

String theory dual of the beta-deformed gauge theory

Chu, Chong-Sun; Khoze, Valentin V.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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We consider the AdS/CFT correspondence between the beta-deformed supersymmetric gauge theory and the type IIB string theory on the Lunin-Maldacena background. Guided by gauge theory results, we modify and extend the supergravity solution of Lunin and Maldacena in two ways. First we make it to be doubly periodic in the deformation parameter, beta -> beta+1 and beta -> beta+tau_0, to match the beta-periodicity property of the dual gauge theory. Secondly, we reconcile the SL(2,Z) symmetry of the gauge theory, which acts on the constant parameters tau_0 and beta, with the SL(2,Z) invariance of the string theory, which involves the dilaton-axion field tau(x). Our modified configuration transforms correctly under the SL(2,Z) of string theory when its parameters are transformed under the SL(2,Z) of the gauge theory. We interpret the resulting configuration as the string theory (rather than supergravity) background which is dual to the beta-deformed conformal Yang-Mills. Finally, we check that our string theory background leads to the IIB effective action which is correctly reproduced by instanton calculations on the gauge theory side, carried out at weak coupling, in the large-N limit, but to all orders in the deformation parameter beta.; Comment: 18 pages...

String Field Theory

Taylor, Washington
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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This elementary introduction to string field theory highlights the features and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string theory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require expanding around a fixed choice of space-time background, the theory is in principle background-independent, in the sense that different backgrounds can be realized as different field configurations in the theory. String field theory is the only string formalism developed so far which, in principle, has the potential to systematically address questions involving multiple asymptotically distinct string backgrounds. Thus, although it is not yet well defined as a quantum theory, string field theory may eventually be helpful for understanding questions related to cosmology in string theory.; Comment: To appear in "Towards Quantum Gravity", ed. Daniele Oriti, Cambridge University Press; 22 pages latex; v2: updated references

Abelian p-Form (p = 1, 2, 3) Gauge Theories as the Field Theoretic Models for the Hodge Theory

Kumar, R.; Krishna, S.; Shukla, A.; Malik, R. P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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Taking the simple examples of an Abelian 1-form gauge theory in two (1 + 1)-dimensions, a 2-form gauge theory in four (3 + 1)-dimensions and a 3-form gauge theory in six (5 + 1)-dimensions of spacetime, we establish that such gauge theories respect, in addition to the gauge symmetry transformations that are generated by the first-class constraints of the theory, additional continuous symmetry transformations. We christen the latter symmetry transformations as the dual-gauge transformations. We generalize the above gauge and dual-gauge transformations to obtain the proper (anti-)BRST and (anti-)dual-BRST transformations for the Abelian 3-form gauge theory within the framework of BRST formalism. We concisely mention such symmetries for the 2D free Abelian 1-form and 4D free Abelian 2-form gauge theories and briefly discuss their topological aspects in our present endeavor. We conjecture that any arbitrary Abelian p-form gauge theory would respect the above cited additional symmetry in D = 2p (p = 1, 2, 3,...) dimensions of spacetime. By exploiting the above inputs, we establish that the Abelian 3-form gauge theory, in six (5 + 1)-dimensions of spacetime, is a perfect model for the Hodge theory whose discrete and continuous symmetry transformations provide the physical realizations of all aspects of the de Rham cohomological operators of differential geometry. As far as the physical utility of the above nilpotent symmetries is concerned...

M(atrix) Theory: Matrix Quantum Mechanics as a Fundamental Theory

Taylor, Washington
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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A self-contained review is given of the matrix model of M-theory. The introductory part of the review is intended to be accessible to the general reader. M-theory is an eleven-dimensional quantum theory of gravity which is believed to underlie all superstring theories. This is the only candidate at present for a theory of fundamental physics which reconciles gravity and quantum field theory in a potentially realistic fashion. Evidence for the existence of M-theory is still only circumstantial---no complete background-independent formulation of the theory yet exists. Matrix theory was first developed as a regularized theory of a supersymmetric quantum membrane. More recently, the theory appeared in a different guise as the discrete light-cone quantization of M-theory in flat space. These two approaches to matrix theory are described in detail and compared. It is shown that matrix theory is a well-defined quantum theory which reduces to a supersymmetric theory of gravity at low energies. Although the fundamental degrees of freedom of matrix theory are essentially pointlike, it is shown that higher-dimensional fluctuating objects (branes) arise through the nonabelian structure of the matrix degrees of freedom. The problem of formulating matrix theory in a general space-time background is discussed...

Orbifolds of M-Theory and Type II String Theories in Two Dimensions

Roy, Shibaji
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/12/1996
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We consider several orbifold compactifications of M-theory and their corresponding type II duals in two space-time dimensions. In particular, we show that while the orbifold compactification of M-theory on $T^9/J_9$ is dual to the orbifold compactification of type IIB string theory on $T^8/I_8$, the same orbifold $T^8/I_8$ of type IIA string theory is dual to M-theory compactified on a smooth product manifold $K3 \times T^5$. Similarly, while the orbifold compactification of M-theory on $(K3 \times T^5)/\sigma ... J_5$ is dual to the orbifold compactification of type IIB string theory on $(K3 \times T^4)/\sigma ... I_4$, the same orbifold of type IIA string theory is dual to the orbifold $T^4 \times (K3 \times S^1)/\sigma ... J_1$ of M-theory. The spectrum of various orbifold compactifications of M-theory and type II string theories on both sides are compared giving evidence in favor of these duality conjectures. We also comment on a connection between Dasgupta-Mukhi-Witten conjecture and Dabholkar-Park-Sen conjecture for the six-dimensional orbifold models of type IIB string theory and M-theory.; Comment: 25 pages, plain latex, no figures

Three Dimensional Gravity and M-Theory

McGuigan, Michael
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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It is well known that string theory can be formulated as two dimensional gravity coupled to matter. In the 2d gravity formulation the central charge of the matter together with a hidden dimension from the conformal factor or Liouville mode determines the Target space dimension. Also the vacuum amplitude of the 2d gravity formulation implies important constraints on the Target space theory associated with modular invariance. In this paper we study a three dimensional gravity approach to M-theory. We find that there are three hidden Liouville type fields coming from the 3d gravity sector and that these together with the number of zero modes of the matter fields determine an eleven dimensional Target space of M theory. We investigate the perturbative vacuum amplitude for the 3d gravity approach to M theory and constraints imposed from SL(3,Z) modular invariance using a method of Dolan and Nappi together with a sum over spin structures which generalizes the SL(2,Z) invariance found in string theory. To introduce gauge fields in M-theory we study the vacuum amplitude on a three annulus and introduce interactions with two dimensional matter on a boundary in analogy with the introduction of gauge fields for open string theory. We study a three dimensional version of M-theory from the 3d gravity perspective and show how it relates to two dimensional type 0A string theory described by a 2d superLiouville theory with c=1 matter and...

F-theory and M-theory perspectives on N=2 supersymmetric gauge theories in four dimensions

Wissanji, Alisha
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/10/2012
Relevância na Pesquisa
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Deformations of the original F-theory background are proposed. These lead to multiple new dualities and physical phenomena. We concentrate on one model where we let seven-branes wrap a multi-centered Taub-NUT space instead of R4. This configuration provides a successful F-theory embedding of a class of recently proposed four-dimensional N = 2 superconformal (SCFT) \`a la Gaiotto. Aspects of Argyres- Seiberg duality, of the new Gaiotto duality, as well as of the branes network of Benini- Benvenuti and Tachikawa are captured by our construction. The supergravity theory for the conformal case is also briefly discussed. Extending our construction to the non-conformal case, we find interesting cascading behavior in four-dimensional gauge theories with N = 2 supersymmetry. Since the analysis of this unexpected phenomenon is quite difficult in the language of type IIB/F-theory, we turn to the type IIA/M-theory description where the origin of the N = 2 cascade is clarified. Using the T-dual type IIA brane language, we first start by studying the N = 1 supersymmetric cascading gauge theory found in type IIB string theory on p regular and M fractional D3-branes at the tip of the conifold. We reproduce the supersymmetric vacuum structure of this theory. We also show that the IIA analog of the non-supersymmetric state found by Kachru...

Real C*-Algebras, United K-Theory, and the Kunneth Formula

Boersema, Jeffrey L.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/08/2002
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We define united K-theory for real C*-algebras, generalizing Bousfield's topological united K-theory. United K-theory incorporates three functors -- real K-theory, complex K-theory, and self-conjugate K-theory -- and the natural transformations among them. The advantage of united K-theory over ordinary K-theory lies in its homological algebraic properties, which allow us to construct a Kunneth-type, non-splitting, short exact sequence whose middle term is the united K-theory of the tensor product of two real C*-algebras A and B which holds as long as the complexification of A is in the bootstrap category. Since united K-theory contains ordinary K-theory, our sequence provides a way to compute the K-theory of the tensor product of two real C*-algebras. As an application, we compute the united K-theory of the tensor product of two real Cuntz algebras. Unlike in the complex case, it turns out that the isomorphism class of the tensor product O_{k+1} otimes O_{l+1} is not determined solely by the greatest common divisor of k and l. Hence we have examples of non-isomorphic, simple, purely infinite, real C*-algebras whose complexifications are isomorphic.; Comment: 67 pages, 13 tables, uses xy-pic for commutative diagrams, to appear in "K-theory"

Topological Strings, Two-Dimensional Yang-Mills Theory and Chern-Simons Theory on Torus Bundles

Caporaso, N.; Cirafici, M.; Griguolo, L.; Pasquetti, S.; Seminara, D.; Szabo, R. J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/09/2006
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We study the relations between two-dimensional Yang-Mills theory on the torus, topological string theory on a Calabi-Yau threefold whose local geometry is the sum of two line bundles over the torus, and Chern-Simons theory on torus bundles. The chiral partition function of the Yang-Mills gauge theory in the large N limit is shown to coincide with the topological string amplitude computed by topological vertex techniques. We use Yang-Mills theory as an efficient tool for the computation of Gromov-Witten invariants and derive explicitly their relation with Hurwitz numbers of the torus. We calculate the Gopakumar-Vafa invariants, whose integrality gives a non-trivial confirmation of the conjectured nonperturbative relation between two-dimensional Yang-Mills theory and topological string theory. We also demonstrate how the gauge theory leads to a simple combinatorial solution for the Donaldson-Thomas theory of the Calabi-Yau background. We match the instanton representation of Yang-Mills theory on the torus with the nonabelian localization of Chern-Simons gauge theory on torus bundles over the circle. We also comment on how these results can be applied to the computation of exact degeneracies of BPS black holes in the local Calabi-Yau background.; Comment: 62 pages...

Topologically Massive Yang-Mills Theory and Link Invariants

Yildirim, Tuna
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/12/2014
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In this thesis, topologically massive Yang-Mills theory is studied in the framework of geometric quantization. This theory has a mass gap that is proportional to the topological mass $m$. Thus, Yang-Mills contribution decays exponentially at very large distances compared to $1/m$, leaving a pure Chern-Simons theory with level number $k$. The focus of this research is the $near$ Chern-Simons limit of the theory, where the distance is large enough to give an almost topological theory, with a small contribution from the Yang-Mills term. It is shown that this almost topological theory consists of two copies of Chern-Simons with level number $k/2$, very similar to the Chern-Simons splitting of topologically massive AdS gravity model. As $m$ approaches to infinity, the split parts add up to give the original Chern-Simons term with level $k$. Also, gauge invariance of the split Chern-Simons theories is discussed for odd values of $k$. Furthermore, a relation between the observables of topologically massive Yang-Mills theory and Chern-Simons theory is obtained. It is shown that one of the two split Chern-Simons pieces is associated with Wilson loops while the other with 't Hooft loops. This allows one to use skein relations to calculate topologically massive Yang-Mills theory observables in the near Chern-Simons limit. Finally...

String Theory or Field Theory?

Marshakov, A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/12/2002
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The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are discussed. This analysis helps better understand the role and place of string theory in the modern picture of the physical world. Even though quantum field theory describes a wide range of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances. It is this task, the creation of such a theory, which string theory, currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments which are our concern in this review.; Comment: 56 pages, 18 figures, LaTeX; based on contribution to Physics Uspekhi