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Dualities, Symmetries and Unbroken Phases in String Theory : Probing the Composite Nature of the String / Dualiteter, Symmetrier och Obrutna Faser i Strängteori : En Utforskning av Strängens Sammansatta NaturEngquist, Johan January 2005 (has links)
The thesis treats aspects of string/M-theory in anti-de Sitter spacetimes and their supersymmetric completions. By applying the AdS/CFT correspondence, as well as models of spin chains and singletons, we try to attain a better understanding of the underlying symmetries and the unbroken phases of string/M-theory. Tensionless string/M-theory in anti-de Sitter spacetime is argued to imply a higher spin gauge symmetry enhancement and to be described by gauged sigma models of multi-singletons as well as by closed singleton strings. Vasiliev's weakly projected equations of symmetric massless higher spin gauge fields in the vector oscillator formulation is shown to follow from a deformation of the singleton model. Various four dimensional minimal as well as non-minimal supersymmetric higher spin gauge theories in the spinor formulation are examined. The minimal higher spin gauge theory based on the symmetry algebra hs(1|4) is elaborated on in an N=1 superspace, illustrating the remarkable fact that the choice of base manifold is not fixed in unfolded dynamics. The importance of the representations saturating the unitarity bounds in anti-de Sitter spacetime is stressed throughout the thesis, with particular emphasis on the singleton and the massless representations. Singletons, and hence massless states, are shown to appear as bound states on the string or p-brane and are localized at cusps. Furthermore, we examine semiclassical string solutions in Type IIB String Theory in AdS(5) x S(5) and their boundary duals in N=4 Super Yang-Mills Theory in d=4 which are constituted out of thermodynamic composite operators. By using integrable spin chain techniques and Bäcklund transformations in the field theory and in the string theory, respectively, the one-loop anomalous dimensions as well as the tower of conserved charges of the composite operators are shown to be in agreement with the energies and the tower of conserved charges associated with the dual string states.
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A qualificação profissional no foco da crítica ao sistema do capital: em busca dos egressos do CEFETCE / The professional qualification at the focus of the critique to the system of capital: in search of CEFETCE egressesMARQUES, Marcelo Santos January 2009 (has links)
MARQUES, Marcelo Santos. A qualificação profissional no foco da crítica ao sistema do capital: em busca dos egressos do CEFETCE. 2009. 387f. Tese (Doutorado em Sociologia) – Universidade Federal do Ceará, Departamento de Ciências Sociais, Programa de Pós- Graduação em Sociologia, Fortaleza-CE, 2009. / Submitted by Liliane oliveira (morena.liliane@hotmail.com) on 2012-01-10T15:37:27Z
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Previous issue date: 2009 / The present Thesis comprises a critical examination of the structure of the working of the system of the capital, in the light of the central contradiction indicated by Karl Marx in the Grundrisse. The expression of the contradiction gets visibility with the substitution for dead labor (machines) of live labor (human direct labor). Therefore, the substance of value becomes empty and the direct laborers are reduced to the condition of appendix of machines they work with, remaining to them the activities of regulating and supporting the automatic complexes. The logical movement of value and the historical course of the process of subsumption of labor to capital provide the hypothesis that the working class were being submitted to a perverse trend that qualifies in a disqualifying manner its aptitudes and abilities. At the same time, that process simplifies the labor and devaluates labor-force. In order to investigate such process of disruption of the world of labor it was crucial to choose an object of research that allowed checking the performance of workers recognized by common sense as highly qualified. That is the reason for which the “search of the egresses of the CEFETCE” in the labor market was the core of the investigation. Technological assets of mechathronics and telematics technicians were investigate. The basic question of the inquiry is to verify to what extent these high-tech operators activate, the gamma of knowledge acquired during theoretical and practical formation at CEFETCE, to their everyday professional activities. Sixty technologists were interviewed, as well as, professors, industrial managers and laborers of various branches of merchandise production. The interviews always were seconded by visits to some productive plants. As a result, the researcher was awarded with a fertile sociological material, pregnant of symbolic expressions and technological constructs. The materiality and the immateriality of the experiences evidenced “the contradiction in process” in the heart of automatic systems of production. In those systems, fetishist production acts are set aside for the direct workers, in the form “caring of” (machines), “watching” (production lines), “looking at” (monitors) and “changing plates” (electronics) etc. / A presente Tese compreende um exame crítico da estrutura de funcionamento do sistema do capital, à luz da contradição central assinalada por Karl Marx nos Grundrisse. A contradição vai se tornando visível com a substituição do trabalho vivo (trabalho humano direto) pelo trabalho morto (máquinas). Em decorrência, esvazia-se a substância do valor e os trabalhadores diretos são reduzidos à condição de apêndice de máquinas que trabalham, restando-lhes as atividades de reguladores e de suportes para complexos automáticos. O movimento lógico do valor e o transcurso histórico do processo de subsunção do trabalho ao capital, propiciam a hipótese de que o conjunto dos trabalhadores estaria sendo submetido a uma tendência perversa que qualifica desqualificando suas aptidões e habilidades. Ao mesmo tempo, simplifica o trabalho e desvaloriza a força-de-trabalho. A fim de averiguar tal processo de disrupção do mundo do trabalho, constituiu-se um objeto de pesquisa que permitisse checar a atuação de trabalhadores tidos, pelo senso comum, como altamente qualificados. Eis a razão pela qual se tomou como plano investigativo, a “busca dos egressos do CEFETCE” no mercado de trabalho, centrando a investigação nos haveres tecnológicos de mecatrônicos e telemáticos. A questão básica é verificar até que ponto esses operadores high-tech ativam a gama dos conhecimentos obtidos em sua formação teórico-prática cefeteana, no dia-a-dia das atividades profissionais. Foram entrevistados sessenta tecnólogos, além de professores, administradores industriários e operários de fábrica vinculados a díspares ramos de produção de mercadorias. As entrevistas foram sempre secundadas por visitas a várias plantas produtivas. Como resultado, o pesquisador foi premiado com um fértil material sociológico, prenhe de expressões simbólicas e de constructos técnicos. A materialidade e a imaterialidade das experiências, explícita e implicitamente vivenciadas, evidenciaram a “contradição em processo” no coração de sistemas de produção automáticos. Nestes, estão reservados para os trabalhadores imediatos atos fetichistas como “cuidar” (de máquinas), “assistir” (linhas de produção), “olhar” (supervisórios) e “trocar placas” (eletrônicas) etc.
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Dräkt och pose i porträtt : En analys av posens fiktion och dräktens avbildning i tre porträtt föreställande Herman Wrangel (1584 - 1643)Bredberg, Eva January 2017 (has links)
This study is concerned with portraiture as a roleplay and a strategy to communicate the sitter´s identity to affect the viewer. Focusing on the sitter´s pose and the depiction of dress, the study examines three portraits between 1624 and the 1630s, representing Herman Wrangel (1584–1643), Field Marshal and Councilor of the Realm. The analysis is based on the concept, the fiction of the pose, developed by Harry Berger Jr. The idea of Theatricality discussed by Hanneke H Grootenboer´s is also used. The results show that dress, details of dress and the pose which are significant for the identity of the sitter are depicted with emphasis. Therefore, the dress and the pose have a key role in the depiction of the sitter acting his identity. The sitter acts before the artist and in the long run before the beholder. The portrait of the nobleman becomes a monologue for the beholder who can confirm the nobility´s role in society. / Uppsatsen handlar om hur porträttmåleri som ett rollspel och en strategi för förmedling av den avporträtterades identitet till betraktaren. Tre porträtt från perioden 1624–1630, föreställande Herman Wrangel (1584–1643) fältmarskalk och riksråd, har analyserats med fokus på den avporträtterades pose och dräktens avbildning med stöd i begreppet the fiction of the pose, baserat på Harry Berger Jr teori. Vidare används begreppet teatrikalitet, som det diskuteras av Hanneke H Grootenboer. Undersökningen visar att dräkt och dräktdetaljer samt poser som är betydelsefulla, för den avporträtterades identitet, framställs med emfas. Därmed spelar dräkten och posen en viktig roll i den avporträtterades framställan. Den avporträtterade agerar inför konstnären och i förlängningen inför betraktaren. Porträttet av adelsmannen blir en uppvisning, en monolog inför betraktaren som kan bekräfta adelsmannens roll i den sociala hierarkin.
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Higher Spins, Entanglement Entropy And HolographyDatta, Shouvik 01 1900 (has links) (PDF)
The idea of holography [1, 2] finds a concrete realization in form of the AdS/CFT correspondence [3, 4]. This duality relates a field theory with conformal symmetries to quantum gravity living in one higher dimension. In this thesis we study aspects of black hole quasinormal modes, higher spin theories and entanglement entropy in the context of this duality. In almost all cases we have been able to subject the duality to some precision tests.
Quasinormal modes encode the spectrum of black holes and the time-scale of pertur-
bations therein [5]. From the dual CFT viewpoint they are the poles of retarded Green's function (or peaks in the spectral function) [6]. Quasinormal modes were previously studied for scalar, gauge field and fermion fluctuations [7]. We solve for these quasinormal modes of higher spin (s _ 2) fields in the background of the BTZ black hole [8, 9]. We obtain an exact solution for a field of arbitrary spin s (integer or half-integer) in the BTZ background. This implies that the BTZ is perhaps the only known black hole background where such an analysis can be done analytically for all bosonic and fermionic fields.
The quasinormal modes are shown to match precisely with the poles of the corresponding Green's function in the CFT living on the boundary. Furthermore, we show that one-loop determinants of higher spin fields can also be written as a product form [10] in terms of these quasinormal modes and this agrees with the same obtained by integrating the heat-kernel [11].
We then turn our attention to dualities relating higher-spin gravity to CFTs with W
algebra symmetries. Since higher spin gravity does go beyond diffeomorphism invariance, one needs re_ned notions of the usual concepts in differential geometry. For example, in general relativity black holes are defined by the presence of the horizon. However, higher spin gravity has an enlarged group of symmetries of which the diffeomorphisms form a subgroup. The appropriate way of thinking of solutions in higher spin gravity is via characterizations which are gauge invariant [12, 13]. We study classical solutions embedded in N = 2 higher spin supergravity. We obtain a general gauge-invariant condition { in terms of the odd roots of the superalgebra and the eigenvalues of the holonomy matrix of the background { for the existence of a Killing spinor such that these solutions are supersymmetric [14].
We also study black holes in higher spin supergravity and show that the partition function of these black holes match exactly with that obtained from a CFT with the same asymptotic symmetry algebra [15]. This involved studying the asymptotic symmetries of the black hole and thereby developing the holographic dictionary for the bulk charges and chemical potentials with the corresponding quantities of the CFT.
We finally investigate entanglement entropy in the AdS3/CFT2 context. Entanglement
entropy is an useful non-local probe in QFT and many-body physics [16]. We analytically evaluate the entanglement entropy of the free boson CFT on a circle at finite temperature (i.e. on a torus) [17]. This is one of the simplest and well-studied CFTs. The entanglement entropy is calculated via the replica trick using correlation functions of bosonic twist operators on the torus [18]. We have then set up a systematic high temperature expansion of the Renyi entropies and determined their finite size corrections. These _nite size corrections both for the free boson CFT and the free fermion CFT were then compared with the one-loop corrections obtained from bulk three dimensional handlebody spacetimes which have higher genus Riemann surfaces (replica geometry) as its boundary [19]. One-loop corrections in these geometries are entirely determined by the spectrum of the excitations present in the bulk. It is shown that the leading _nite size corrections obtained by evaluating the one-loop determinants on these handlebody geometries exactly match with those from the free fermion/boson CFTs. This provides a test for holographic methods to calculate one-loop corrections to entanglement entropy.
We also study conformal field theories in 1+1 dimensions with W-algebra symmetries at
_nite temperature and deformed by a chemical potential (_) for a higher spin current. Using OPEs and uniformization techniques, we show that the order _2 correction to the Renyi and entanglement entropies (EE) of a single interval in the deformed theory is universal [20]. This universal feature is also supported by explicit computations for the free fermion and free boson CFTs { for which the EE was calculated by using the replica trick in conformal perturbation theory by evaluating correlators of twist fields with higher spin operators [21]. Furthermore, this serves as a verification of the holographic EE proposal constructed from Wilson lines in higher spin gravity [22, 23].
We also examine relative entropy [24] in the context of higher-spin holography [25]. Relative entropy is a measure of distinguishability between two quantum states. We confirm the expected short-distance behaviour of relative entropy from holography. This is done by showing that the difference in the modular Hamiltonian between a high-temperature state and the vacuum matches with the difference in the entanglement entropy in the short-subsystem regime.
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Stabilité des bulles de masse négative dans un espace-temps de de SitterSavard, Antoine 08 1900 (has links)
L'existence de la masse négative a un sens parfaitement physique du moment que les conditions d'énergie dominante sont satisfaites par le tenseur énergie-impulsion correspondant. Jusqu'à maintenant, seules des configurations de masses négatives avaient été trouvées. On démontre l'existence de bulles de masse négative stables dans un espace-temps qui s'approche asymptotiquement d'un espace-temps de de Sitter. Les bulles sont des solutions aux équations d'Einstein qui correspondent à une région intérieure qui contient une distribution de masse spécifique séparée par une coquille mince de l'espace-temps à masse négative de Schwarzschild-de Sitter à l'extérieur.
Ensuite, on applique les conditions de jonction d'Israel à la frontière de la bulle ce qui impose la conservation d'énergie-impulsion à travers la surface. Les conditions de jonction donnent une équation pour un potentiel pour le rayon de la bulle qui dépend de la distribution de masse à l'intérieur, ou vice versa.
Finalement, on trouve un potentiel qui aboutit à une solution stable, statique et non-singulière, ce qui crée une distribution de masse interne qui satisfait les conditions d'énergie dominante partout à l'intérieur. Cependant, la bulle ne satisfait pas ces conditions. De plus, on trouve une solution stable, statique et non-singulière pour une géométrie interne de de Sitter pure. La solution est fondamentalement différente: elle requiert que la densité d'énergie de la bulle change avec le rayon. La condition d'énergie dominante est satisfaite partout. / Negative mass makes perfect physical sense as long as the dominant energy condition is satisfied by the corresponding energy-momentum tensor. Until now, only configurations of negative mass have been found. We demonstrate the existence of stable, negative-mass bubbles in an asymptotic de Sitter space-time. The bubbles are solutions of the Einstein equations which correspond to an interior region of space-time containing a specific distribution of mass separated by a thin wall from the exact, negative mass Schwarzschild-de Sitter space-time in the exterior.
Then, we apply the Israel junction conditions at the wall which impose the conservation of energy and momentum across the wall. The junction conditions give rise to an effective potential for the radius of the wall that depends on the interior mass distribution, or vice versa.
Finally, we find a potential that gives rise to stable, non-singular, static solutions, which yields an interior mass distribution that everywhere satisfies the dominant energy condition. However, the energy momentum of the wall does not satisfy the dominant energy condition. Moreover, we find a stable, non-singular, static solution for a pure de Sitter geometry inside the bubble. The solution is fundamentally different: the energy density of the bubble is no longer a constant, but now varies with the radius. The dominant energy condition is everywhere satisfied.
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Quantum gravity in two- and three-dimensional dS spacesChernichenko, Alexsey January 2024 (has links)
This thesis is a study of certain aspects of quantum gravity in two- and three-dimensional de Sitter spaces. The model used in dS2 is the Jackiw- Tetitelboim gravity which involves a scalar coupling. At low-energy limit this model becomes Schwarzian theory for which one can compute one-loop partition function. Along the way, the model is recasted into the first order formalism which helps to find an appropriate measure for the partition function. The layout for quantum gravity in dS3 is practically the same and many results appear to be quite similar. Although, there are as many dissimilarities. Ultimately, the goal is different, namely to determine one-loop correction to the central charge of the theory dual to dS3 . Additionally, a putative genus expansion for Jackiw-Teitelboim gravity is investigated along with some concrete computations being done. / Detta examensarbete ̈ar en studie av vissa aspekter av kvantgravita-tion i två och tredimensionella de Sitter-rummen. Den behandlar Jackiw-Teitelboim gravitation i dS2 , en model med en skalär koppling. Vid lågenergigränns blir modellen till Schwarzian teorin som används för att beräkna första ordningskorrektionen till partitionsfunktion. På vägen dit skrivs om modelen till första ordningens formalism som sedan hjälper att hitta ett lämpligt mått för partitionsfunktionen. Plannen för dS3 ser ut i princip likadant och en stor del av resultater är liknande. Emellertid finns det lika många olikheter. I slut änden, målet är annorludna, nämligen att beräkna första ordningens korrektion till centrala laddningen av teorin som dual till dS3 . Dessutom, en förmodad genus expansion för Jackiw-Teitelboim gravitation är undersökt och vissa konkreta beräkningar är gjorda.
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