Dissertationen: „D-branes“

1

Lambert, N. D., I. Sachs und Andreas Cap@esi ac at. „String Loop Corrections to Stable Non--BPS Branes“. J. High Energy Phys. 02 (2001), paper 018, 2000. ftp://ftp.esi.ac.at/pub/Preprints/esi954.ps.

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2

Reis, Rui Miguel Goncalves dos Reis. „K-homology and D-branes“. Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/2149.

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In the spirit of the work of P. Baum and R. Douglas in K-homology, we construct a set of abelian groups which define homotopy functors from the category of finite CWpairs onto the category of graded abelian groups. These we prove to be isomorphic to the geometric representation of KO-homology, the homology theory associated to KO-theory, constructed by M. Jakob. It is known that KO-homology has an analytic representation defined in terms of the C*-algebra of continuous functions over a space and of Kasparov's KK-theory. The third chapter presents our proof of the equivalence between this analytic representation of KO-homology and our geometric constructions. Applying our mathematical constructions, we explicitly describe various aspects of D-branes in Type II superstring theory in the absence of background supergravity form fields. Also, we study the classification of D-branes and Ramond-Ramond fields in Type I string theory and show that the AMS invariant naturally assigns torsion charges to non-BPS states in Type I string theory.

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3

Jia, Bei. „D-branes and K-homology“. Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/32039.

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In this thesis the close relationship between the topological $K$-homology group of the spacetime manifold $X$ of string theory and D-branes in string theory is examined. An element of the $K$-homology group is given by an equivalence class of $K$-cycles $[M,E,\phi]$, where $M$ is a closed spin$^c$ manifold, $E$ is a complex vector bundle over $M$, and $\phi: M\rightarrow X$ is a continuous map. It is proposed that a $K$-cycle $[M,E,\phi]$ represents a D-brane configuration wrapping the subspace $\phi(M)$. As a consequence, the $K$-homology element defined by $[M,E,\phi]$ represents a class of D-brane configurations that have the same physical charge. Furthermore, the $K$-cycle representation of D-branes resembles the modern way of characterizing fundamental strings, in which the strings are represented as two-dimensional surfaces with maps into the spacetime manifold. This classification of D-branes also suggests the possibility of physically interpreting D-branes wrapping singular subspaces of spacetime, enlarging the known types of singularities that string theory can cope with.
Master of Science

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4

Rovai, Antonin. „Emergent geometry from D-Branes“. Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209425.

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In this thesis, we explain and illustrate on several examples how to derive supergravity solutions by computing observables in the corresponding dual, lower-dimensional field theory.

In particular, no a priori knowledge on the gravitational dual is assumed, including its dimensionality. The basic idea to construct the pre-geometric models is to consider the world-volume theory of probe D-branes in the presence of a large number N of higher-dimensional background branes. In the standard decoupling limit, the probes are moving only in the flat directions parallel to the background D-branes. We show however that the quantum effective action of the probe world-volume theory, obtained at large $N$ using standard vector model techniques, has the required field content to be interpreted as the action describing the probes in a higher-dimensional, curved and classical spacetime. The properties of the emerging supergravity solution are easily found by comparing the quantum effective action of the pre-geometric model with the non-abelian D-brane action. In all the examples we consider, this allows us to derive the metric, the dilaton and various form fields, overall performing exclusively field theoretic computations.

The first part of the thesis consists of introductory chapters, where we review vector models at large N, aspects of brane physics in supergravity and string theory and the gauge/gravity correspondence. The second part contains the original contributions of this thesis, consisting of various explicit emergent geometry examples.

Doctorat en Sciences
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5

Winters, David J. „Aspects of D-branes : from branes in motion to meson spectroscopy“. Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84855.

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We discuss various aspects of D-branes, ranging from their basic properties as extended objects within string theory to their application, via the AdS/CFT correspondence, to the physics of gauge theories. Our initial emphasis is on the description of time-dependent, yet supersymmetric, brane configurations and to this end we first provide a review of established results on D-branes. We then investigate various supersymmetric brane intersections. Motivated by the recent results on supertubes, we investigate general constraints under which parallel brane-antibrane configurations are supersymmetric. Dual descriptions of these configurations involve systems of intersecting branes in relative motion. In particular, we find new supersymmetric configurations which are not related to a static brane intersection by a boost. In these new configurations, the intersection point moves at the speed of light. We then briefly review the AdS/CFT correspondence between string and gauge theories. Our emphasis here is on the recent development of D-brane configurations that can be used to add fundamental flavour to the gauge theories. We compute the meson spectrum of an N = 2 super Yang-Mills theory with fundamental matter from its dual string theory on AdS5 x S 5 with a D7-brane probe. For scalar and vector mesons with arbitrary R-charge the spectrum is computed in closed form by solving the equations for D7-brane fluctuations; for matter with non-zero mass mq it is discrete and exhibits a mass gap of order mq/ gsN . The spectrum of mesons with large spin J is obtained from semiclassical, rotating open strings attached to the D7-brane. It displays Regge-like behaviour for J ≪gsN , whereas for J ≫gsN it corresponds to that of two non-relativistic quarks bound by a Coulomb potential.

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6

Scheidegger, Emanuel. „D-branes on Calabi-Yau spaces“. [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963248308.

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7

Wurtz, Albrecht. „Conformal Field Theory and D-branes“. Doctoral thesis, Karlstad University, Faculty of Technology and Science, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1346.

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The main topic of this doctoral thesis is D-branes in string theory, expressed in the language of conformal field theory. The purpose of string theory is to describe the elementary particles and the fundamental interactions of nature, including gravitation as a quantum theory. String theory has not yet reached the status to make falsifiable predictions, thus it is not certain that string theory has any direct relevance to physics. On the other hand, string theory related research has led to progress in mathematics.

We begin with a short introduction to conformal field theory and some of its applications to string theory. We also introduce vertex algebras and discuss their relevance to conformal field theory. Some classes of conformal field theories are introduced, and we discuss the relevant vertex algebras, as well as their interpretation in terms of string theory.

In string theory, a D-brane specifies where the endpoint of the string lives. Many aspects of string theory can be described in terms of a conformal field theory, which is a field theory that lives on a two-dimensional space. The conformal field theory counterpart of a D-brane is a boundary state, which in some cases has a natural interpretation as constraining the string end point. The main focus of this thesis is on the interpretation of boundary states in terms of D-branes in curved target spaces.

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8

Smedbäck, Mikael. „Topics on D-branes and Holography“. Doctoral thesis, Uppsala University, Department of Theoretical Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4478.

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We discuss various aspects of D-branes in string theory and holography in string theory and loop quantum gravity.

One way to study D-branes is from a microscopic perspective, using conformal field theory techniques. For example, we investigate the question of how D-branes can be introduced into orbifolded theories. Another way to study D-branes is from a space-time perspective. An example is provided by unstable D-branes, where we compute an effective action describing the decay of a bosonic D-brane.

The holographic principle is a proposed duality which suggests that a theory in any region has a dual description on the boundary. We explore two examples: (1) The area law for the entropy of a black hole in the framework of loop quantum gravity, related to particular regularizations of the area operator. (2) The AdS/CFT correspondence proposal, where we investigate a string pulsating on AdS using spin chains.

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9

Scheidegger, Emanuel Gilbert. „D-branes on Calabi-Yau Spaces“. Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-4451.

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10

Smedbäck, Mikael. „Topics on D-branes and holography /“. Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4478.

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11

Sigalov, Ilya. „D-branes and string field theory“. Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/39560.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.
Includes bibliographical references (p. 115-127).
In this thesis we study the D-brane physics in the context of Witten's cubic string field theory. We compute first few terms the low energy effective action for the non-abelian gauge field A, from Witten's action. We show that after the appropriate field redefinition which relates the string field theory variables to the worldsheet variables one obtains the correct Born-Infeld terms. We then compute the rolling tachyon solution in the context of string field theory. We show that after the appropriate field redefinition we obtain the rolling tachyon solution of Sen.
by Ilya Sigalov.
Ph.D.

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12

Fredenhagen, Stefan. „Dynamics of D-branes in curved backgrounds“. Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965704017.

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13

Pawelczyk, Jacek, Soo-Jong Rey und jacek pawelczyk@physik uni-muenchen de. „Ramond--Ramond Flux Stabilization of D--Branes“. ESI preprints, 2000. ftp://ftp.esi.ac.at/pub/Preprints/esi955.ps.

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14

Wulff, Linus. „Strings, boundary fermions and coincident D-branes“. Doctoral thesis, Stockholm : Department of Physics, Stockholm University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6576.

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15

O'Driscoll, D. C. „D-branes and orientifolds in string theory“. Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638350.

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We examine the interplay of supersymmetry and compactification on D-branes and orientifold planes using the framework of superstring theory. We explore issues pertinent to geometrical descriptions of these theories and dualities among them.

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16

Barrett, Jessica K. „Aspects of D-branes as BPS monopoles“. Thesis, Durham University, 2004. http://etheses.dur.ac.uk/3160/.

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We investigate some of the properties of D-brane configurations which behave as BPS monopoles. The two D-brane configurations we will study are the enhançon and D-strings attached to D3-branes.We will start by investigating D3-branes wrapped on a K3 manifold, which are known as enhançons. They look like regions of enhanced gauge symmetry in the directions transverse to the branes, and therefore behave as BPS monopoles. We calculate the metric on moduli space for n enhançons, following the methods used by Ferrell and Eardley for black holes. We expect the result to be the higher-dimensional generalisation of the Taub-NUT metric, which is the metric on moduli space for n BPS monopoles. Next we will study D-strings attached to D3-branes; the ends of the D-strings behave as BPS monopoles of the world volume gauge theory living on the D3-branes. In fact the D-string/D3-brane system is a physical realisation of the ADHMN construction for BPS monopoles. We aim to test this correspondence by calculating the energy radiated during D-string scattering, working with the non-Abelian Born-Infeld action for D-strings. We will then compare our result to the equivalent monopole calculation of Manton and Samols.

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17

Parra, Milián S. [UNESP]. „Classical solutions for D-branes in AdS“. Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/127600.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
No presente trabalho comprometemo-nos ao estudo de soluções clássicas para D-branas no espaço de Anti-de Sitter, as quais surgem da solução de órbita do subgrupo estabilizador de um ponto na fronteira no espaço AdS. Começamos por fazer uma breve revisão da teoria de supercordas e apresentamos algumas características da geometria do espaço AdS. Então fazemos uma discussão sobre a ação efetiva a baixas energias e, por último, escrevemos a ação de uma D3-brana no espaço AdS5. O estudo desta solução particular da D-brana não é completo e acaba por fugir ao escopo deste trabalho. Esperamos complementá-lo num futuro breve e, com isto em mente, concluímos a dissertação com um resumo de deformações marginais da teoria de campo N = 4 SYM e sua gravidade dual
The main result of this dissertation is the study of the classical solutions for D-brane in Anti-de Sitter(AdS) space. They arised from the study of the orbit solution of the stablizer subgroup of a point on the boundary of the AdS space. To reach this goal we started making a brief summary of superstring theories, then we presented some geometric facts of the AdS space. A discussion of the effective low-energy action of a bosonic D-brane was done, then we wrote the action of a single D3-brane in the AdS5 space. Unfortunately, the study of this particular D-brane solution is not complete and goes beyond the scope of this dissertation. We intend to complete this work in the future, with this in mind a summary of the marginal deformation of N = 4 SYM ﬁeld theory and its gravity dual were given in the last chapter
CAPES: 33015015001P7

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18

Parra, Milián S. (Segundo). „Classical solutions for D-branes in AdS /“. São Paulo, 2014. http://hdl.handle.net/11449/127600.

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Orientador: Andrey Yuryevich Mikhaylov
Banca: Nathan Jacob Berkovits
Banca: Vladimir Perchine
Resumo: No presente trabalho comprometemo-nos ao estudo de soluções clássicas para D-branas no espaço de Anti-de Sitter, as quais surgem da solução de órbita do subgrupo estabilizador de um ponto na fronteira no espaço AdS. Começamos por fazer uma breve revisão da teoria de supercordas e apresentamos algumas características da geometria do espaço AdS. Então fazemos uma discussão sobre a ação efetiva a baixas energias e, por último, escrevemos a ação de uma D3-brana no espaço AdS5. O estudo desta solução particular da D-brana não é completo e acaba por fugir ao escopo deste trabalho. Esperamos complementá-lo num futuro breve e, com isto em mente, concluímos a dissertação com um resumo de deformações marginais da teoria de campo N = 4 SYM e sua gravidade dual
Abstract: The main result of this dissertation is the study of the classical solutions for D-brane in Anti-de Sitter(AdS) space. They arised from the study of the orbit solution of the stablizer subgroup of a point on the boundary of the AdS space. To reach this goal we started making a brief summary of superstring theories, then we presented some geometric facts of the AdS space. A discussion of the effective low-energy action of a bosonic D-brane was done, then we wrote the action of a single D3-brane in the AdS5 space. Unfortunately, the study of this particular D-brane solution is not complete and goes beyond the scope of this dissertation. We intend to complete this work in the future, with this in mind a summary of the marginal deformation of N = 4 SYM ﬁeld theory and its gravity dual were given in the last chapter
Mestre

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19

Feng, Bo 1971. „D-branes, gauge theory and string field theory“. Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8491.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 2002.
Includes bibliographical references (p. 245-262).
In this thesis, we present several works done in last three years. They include three directions in the string theory. In the first direction, we use the brane setup to find mirror pairs of SO(n) and Sp(k) gauge groups for N = 4 three-dimensional gauge field theories. To reach this result, we analyze carefully the s-configuration and predict a nontrivial string dynamics, i.e., the splitting of branes on the orientifold planes. In the second direction, we develop the "inverse algorithm" and use it to get nontrivial world volume theories of D-branes probing more exotic singularities. In this process, we find the "toric duality" which relates different phases of D-brane probe theories. We realize later that the toric duality is an example of the more powerful Seiberg-duality so these different phases are related by the Seiberg duality. In the third direction, by using numerical calculation we get a strong evidence to support the second conjecture of Sen's three conjectures. We show that if the identity field is BRST exact state around the tachyon vacuum, the open string spectrum will decouple from the physics and leave only the closed string spectrum.
by Bo Feng.
Ph.D.

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20

Valentino, Alessandro. „K-theory, D-branes and Ramond-Ramond fields“. Thesis, Heriot-Watt University, 2008. http://hdl.handle.net/10399/2175.

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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 CW-complexes, and prove that this homology theory is equivalent to the bordism 3n of KO-homology, the dual theory to KO-theory. We construct an isomorphism between our geometric representation and the SLUdlytic 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.

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21

Berenstein, David Eliecer. „Dynamical aspects of D-branes and matrix theory /“. Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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22

Maraventano, Sara. „Superspace formulation of higher-derivative actions from D-branes“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15828/.

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Higher-derivative operators play a fundamental role in the development of effective field theories. This thesis deals with the study of such operators in the context of the effective low-energy theory of type IIB superstring theory. In particular, we revisit a past attempt to find the supersymmetric form of the higher-derivatives for the D7-brane modulus in an orbifold compactification at the level of a globally supersymmetric theory. These higher-derivatives descend from the Dirac-Born-Infeld action of the D7-brane. Starting from the component Lagrangian the task is to identify the supersymmetric higher-derivative operator which reproduces the component terms. To this end, we develop a new systematic approach to determine this supersymmetric form and test it for the present example.

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23

Schäfer-Nameki, Sakura. „D-branes in boundary field theory and K-theory“. Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620017.

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24

Ribault, Sylvain Gae͏̈tan. „Cordes et D-branes dans les espaces-temps courbes“. Palaiseau, Ecole polytechnique, 2003. http://www.theses.fr/2003EPXX0009.

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25

Quella, Thomas. „Asymmetrically gauged coset theories and symmetry breaking D-branes“. Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2003. http://dx.doi.org/10.18452/14909.

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Auf sehr kleinen Längenskalen erlaubt die Weltflächenbeschreibung über zweidimensionale konforme Feldtheorien eine störungstheoretische Definition der String-Theorie. Viele strukturelle Eigenschaften und phänomenologische Implikationen der letzteren können mit Hilfe von D(irichlet)-Branen untersucht werden, die in der zugrunde liegenden Weltflächentheorie durch konforme Randbedingungen beschrieben werden. Etliche interessante Hintergründe für die String-Theorie erhält man über Gruppenmannigfaltigkeiten und Coset-Modelle. Neben wichtigen Beispielen wie SL(2,R), SU(2) und Gepner-Modellen, die für AdS- und Calabi-Yau-Kompaktifizierungen eine Rolle spielen, beinhalten sie außerdem weitere Beispiele wie den Nappi-Witten-Hintergrund oder den Raum T^11, die über eine asymmetrische Wirkung der Eichgruppe definiert sind und eine kosmologische Raumzeit mit Urknall- und Weltsturz-Singularitäten bzw. die Basis des Conifolds beschreiben. Die vorliegende Arbeit bietet eine umfassende, auf den exakten Methoden der konformen Feldtheorie beruhende Analyse von asymmetrischen Coset-Modellen. Wegen der heterotischen Natur der zugrundeliegenden Symmetriealgebra erlauben diese Modelle nur Randbedingungen, die einen Teil der Symmetrie brechen. Nach einer allgemeinen Erläuterung der Grundidee für die Konstruktion von symmetriebrechenden Randbedingungen richtet sich das Hauptaugenmerk auf WZNW- und asymmetrische Coset-Modelle, die das Fundament nahezu aller bekannten konformen Feldtheorien bilden. Mit Hilfe der erzielten Ergebnisse werden die Struktur sowie die Geometrie von D-Branen in den Gruppen SL(2,R) und SU(2), im Hintergrund AdS_3 x S^3, in der kosmologischen Nappi-Witten-Raumzeit und in T^pq-Räumen untersucht. Die Techniken, die in dieser Arbeit entwickelt werden, erlauben jedoch ebenso die Behandlung von Rändern und Kontaktstellen in (1+1)- oder 2-dimensionalen kritischen Systemen, die in der Festkörpertheorie oder der statistischen Physik auftreten. Insbesondere können Defektlinien beschrieben werden, die weder totale Reflexion noch völlige Transmission aufweisen.
At very small length scales, the world sheet approach in terms of two-dimensional conformal field theories provides a perturbative definition of string theory. Many structural properties and phenomenological implications of the latter can be explored using D(irichlet)-branes which may be identified with conformal boundary conditions in the underlying world sheet theory. Several interesting backgrounds in string theory arise from group manifolds and coset theories. Apart from prominent examples such as SL(2,R), SU(2) and Gepner models which play a role in AdS and Calabi-Yau compactifications, they also include further instances like the Nappi-Witten background or the space T^11 which are constructed using an asymmetric action of the gauge group and which describe a cosmological space-time with big-bang and big-crunch singularities and the base of the conifold, respectively. The present thesis provides a comprehensive analysis of asymmetric cosets based on the exact methods of boundary conformal field theory. Due to the heterotic nature of the underlying symmetry algebra, the models only allow for conformal boundary conditions which break parts of the bulk symmetry. The universal ideas for the construction of symmetry breaking boundary conditions are indicated and applied in detail to WZNW and asymmetric coset theories which provide the basic building blocks of almost all known conformal field theories. The general results are used to investigate the structure and shape of D-branes in the group manifolds SL(2,R) and SU(2), the background AdS_3 x S^3, the cosmological Nappi-Witten space-time and T^pq-spaces. The techniques developed in this thesis also allow for a treatment of boundaries and junctions in (1+1)- or 2-dimensional critical systems in condensed matter theory and statistical physics. In particular, they enable us to describe defect lines which go beyond full reflection or transmission.

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26

Closset, Cyril. „Studies of fractional D-branes in the gauge/gravity correspondence & flavored Chern-Simons quivers for M2-branes“. Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210125.

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Cette thèse intitulée « Studies of fractional D-branes in the gauge/gravity correspondence & Flavored Chern-Simons quivers for M2-branes » se place dans le cadre de la théorie des cordes, en physique théorique. Elle consiste en une introduction suivie de deux parties. Dans l'introduction sont résumés les différents outils de théorie des cordes qui seront utilisés.

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Doctorat en Sciences
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27

Dawson, Peter Dale. „Effective actions and charges of D-branes in curved space-time“. Title page, abstract and contents only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phd2727.pdf.

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Bibliography: leaves 181-190. This thesis firstly investigates K-invariant and supersymmetric actions of D-branes in curved space-time. Following this, research into charges of D-branes in a group manifold are studied. In particular, the charge groups are determined for the symmetry preserving (or untwisted) D-branes on a compact, simple, connected, simply connected group manifold. The purpose of this research is to determine these charge groups in order that they can be compared to the charge groups predicted by twisted K-theory for D-branes in a group manifold, thus providing a future important check to the theorem that D-brane charges are determined by twisted K-theory, one of the most important recent ideas in string theory.

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28

Goi, Enrico. „Quelques aspects de la brisure de supersymétrie en théorie des cordes de types IIA : vides et déformations“. Paris 7, 2011. http://www.theses.fr/2011PA077172.

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Cette thèse porte sur l'étude des compactifîcations non-supersymétriques avec flux en théorie des cordes de type IIA. Après une introduction aux théories de type II, nous introduisons le cadre mathématique de la Géométrie Complexe Généralisée, celle ci donne une interprétation géométrique des vides supersymétriques et un principe permettant de les organiser. Nous introduisons la classe des solvmanifolds, qui ont été largement utilisées comme variétés de compactification, et discutons leurs propriétés mathématiques, notament les critères de compacité. Nous présentons ensuite notre premier exemple de compactification non-supersymétrique, un vide qui a pour espace externe un espace de Sitter. Nous résolvons les équations du mouvement et dans le même temps nous discutons le comportement de D-branes dans les fonds non- supersymétriques. Une brève analyse de la physique à quatre dimensions est également fournie. Nous spéculons sur l'utilisation de la Géométrie Généralisée pour les vides non-supersymétriques et sur leur structure géométrique. Motivé par des considérations issues de la dualité AdS/CFT nous analysons un vide non-supersymétrique, censé être le correspondant gravitationnel d'un vide métastable non supersymétrique d'une théorie de jauge supersymétrique. La supersymétrie est ici brisée par l'ajout d' anti-branes, dont il est notoirement difficile de prendre en compte la contre réaction. Ainsi nous avons recours à l'utilisation d'une technique perturbative. Nous calculons les déformations du premier ordre d'un fond D2-brane, discutons l'espace des solutions et argumentons sur la nature des singularités inévitables que nous rencontrons dans le processus
This thesis is devoted to the study of non-supersymmetric flux compactifications in type IIA string theory. After a brief review of type II theories, we introduce the mathematical framework of Generalized Complex Geometry, which provides an encompassing geometric interpretation and organizing principle for supersymmetric vacua. We introduce the class of solvmanifolds, which have been extensively used as compactification manifolds, and discuss their mathematical properties, with particular attention to the compactness criteria. We then present our first example of non-supersymmetric compactification, a vacuum which has a de Sitter external space. We solve the equations of motion and in the process we argue about the behaviour of D-branes in non-supersymmetric backgrounds; a short analysis of the four dimensional physics is also provided. We speculate about the use of Generalized Geometry for non-supersymmetric vacua too and about the right variables to describe the supposed underlying geometric structure. Motivated by AdS/CFT considerations we investigate a supersymmetry breaking vacuum which is supposed to be the gravity dual to a metastable non-supersymmetric vacuum of a supersymmetric gauge theory. Supersymmetry is here broken by the addition of anti-branes; it is notoriously difficult to take into account their backreaction and we resort to use a perturbative technique. We compute the most general first order deformations of a D2-brane background, discuss the space of solutions of the deformed fields and argue about the nature of the unavoidable singularities which we encounter in the process

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29

Liyanage, Christoph [Verfasser]. „Yukawa Couplings from D-branes on non-factorisable Tori / Christoph Liyanage“. Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1167856961/34.

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30

Krippendorf, Sven-Ludwig. „D-brane model building and moduli stabilisation in type IIB string theory“. Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609632.

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31

Moskovic, Micha. „Holographic backgrounds from D-brane probes“. Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209307.

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The gauge/string correspondence provides a non-perturbative definition of string theory and hence quantum gravity in some backgrounds, making it possible to translate statements about strongly coupled quantum field theories into results about gravity.

In this thesis, we focus on the derivation of holographic backgrounds from the field theory, without using any supergravity input. Instead, we rely crucially on the addition of probe D-branes to the stack of D-branes generating the background.

From the field theory description of the probe branes in the presence of the background branes, one can compute an effective action for the probes (in a suitable low-energy/near-horizon limit) by integrating out the background branes. Comparing this action with the D-brane probe action in a generic supergravity background then allows to determine the holographic background dual to the considered field theory vacuum.

In the first part, the required pre-requisites of field and string theory are recalled and this strategy to derive holographic backgrounds is explained in more detail on the basic case of D3-branes in flat space probed by a small number of D-instantons.

The second part contains the original results of this thesis, obtained by applying this strategy to several specific examples. We first derive the duals to three continuous deformations (Coulomb branch, β and non-commutative deformations) of the basic case, in the limit in which the D-instantons can probe the full geometry. We then derive the enhançon mechanism in a dual to a simple N=2 quiver gauge theory by using a fractional D-instanton as a probe and exploiting recent exact results on the Coulomb branch of N=2 quivers.

Finally, we obtain the near-horizon D4-brane geometry by probing the D4-branes with a small number of D0-branes.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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32

Couchoud, Nicolas. „D-branes et orientifolds dans des espaces courbes ou dépendant du temps“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00008263.

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Dans cette thèse nous étudions la théorie des cordes en présence de
D-branes et éventuellement d'orientifolds dans des espaces courbes ou dépendants du temps. Notre étude vise à comprendre certains aspects des espaces courbes et dépendant du temps, notamment à cause de leur importance en cosmologie.

Le premier chapitre introduit quelques bases de la théorie des cordes.

Le deuxième chapitre étudie les cordes non orientées sur les groupes compacts SU(2) et SO(3) : après un rappel des résultats connus sur les D-branes dans ces espaces, nous présentons nos résultats sur la position des orientifolds et leur interaction avec les cordes ouvertes et fermées.

Le troisième chapitre étudie les D-branes dans certains fonds de type Ramond-Ramond, en utilisant la S-dualité qui les relie à des fonds de type Neveu-Schwarz, où on sait faire les calculs.

Le dernier chapitre considère les cordes sur une D-brane parcourue par une onde plane, et introduit les outils y permettant l'étude des interactions.

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33

Franco, Sebastián Federico. „Duality and dynamics of supersymmetric field theories from D-branes on singularities“. Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32298.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2005.
Includes bibliographical references (p. 359-373).
We carry out various investigations regarding gauge theories on the worldvolume of D-branes probing toric singularities. We first study the connection that arises in Toric Duality between different dual gauge theory phases and the multiplicity of fields in the gauged linear sigma models associated with the probed geometries. We introduce a straightforward procedure for the determination of toric dual theories and partial resolutions based on the (p, q) web description of toric singularities. We study the non-conformal theories that arise in the presence of fractional branes. We introduce a systematic procedure to study the resulting cascading RG flows, including the effect of anomalous dimensions on beta functions. Supergravity solutions dual to logarithmic RG flows are constructed, validating the field theory analysis of the cascades. We systematically study the IR dynamics of cascading gauge theories. We show how the deformation in the dual geometries is encoded in a quantum modification of the moduli space. We construct an infinite family of superconformal quiver gauge theories which are AdS/CFT dual to Sasaki-Einstein horizons with explicit metrics. The gauge theory and geometric computations of R-charges and central charges are shown to agree. We introduce new Type IIB brane constructions denoted brane tilings which are dual to D3-branes probing arbitrary toric singularities. Brane tilings encode both the quiver and superpotential of the gauge theories on the D-brane probes. They give a connection with the statistical model of dimers.
(cont.) They provide the simplest known method for computing toric moduli spaces of gauge theories, which reduces to finding the determinant of the Kasteleyn matrix of a bipartite graph.
by Sebastián Federico Franco.
Ph.D.

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34

Goodsell, Mark Dayvon. „One loop phenomenology of type II string theory : intersecting d-branes and noncommutativity“. Thesis, Durham University, 2007. http://etheses.dur.ac.uk/2915/.

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We examine one loop amplitudes for open and closed strings in certain D-brane configurations, and investigate the consequences for phenomenology. Initially we consider open strings at D6-brane intersections. We develop techniques for one-loop diagrams. The one-loop propagator of chiral intersection states is calculated exactly and its finiteness is shown to be guaranteed by RR tadpole cancellation. The result is used to demonstrate the expected softening of power law running of Yukawa couplings at the string scale. We also develop methods to calculate arbitrary TV-point functions at one-loop, including those without gauge bosons in the loop. These techniques are also applicable to heterotic orbifold models. One issue of the intersecting D6-brane models is that the Yukawa couplings of the simpler models suffer from the so-called "rank one" problem - there is only a single non-zero mass and no mixing. We consider the one-loop contribution of E2-instantons to Yukawa couplings on intersecting D6-branes, and show that they can provide a solution. In addition they have the potential to provide a geometric explanation for the hierarchies observed in the Yukawa couplings. In order to do this we provide the necessary quantities for instanton calculus in this class of background. We then explore how the IR pathologies of noncommutative field theory are resolved when the theory is realized as open strings in background B-fields: essentially, since the IR singularities are induced by UV/IR mixing, string theory brings them under control in much the same way as it does the uv singularities. We show that at intermediate scales (where the Selberg-Witten limit is a good approximation) the theory reproduces the noncommutative field theory with all the (un)usual features such as UV/IR mixing, but that outside this regime, in the deep infra-red, the theory flows continuously to the commutative theory and normal Wilsoman behaviour is restored. The resulting low energy physics resembles normal commutative physics, but with additional suppressed Lorentz violating operators. We also show that the phenomenon of UV/IR mixing occurs for the graviton as well, with the result that, in configurations where Planck's constant receives a significant one-loop correction (for example brane-induced gravity), the distance scale below which gravity becomes non-Newtonian can be much greater than any compact dimensions.

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35

Irie, Hirotaka. „String fields, matrix models and D-branes in (p,q) minimal superstring theory“. 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136869.

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36

Mattiello, Luca [Verfasser], und Ivo [Akademischer Betreuer] Sachs. „On instantons and finite-size D-Branes in string theory / Luca Mattiello ; Betreuer: Ivo Sachs“. München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1196968578/34.

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37

Mayes, Van Eric. „Phenomenology of heterotic and type II orientifold string models“. [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1597.

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38

Condeescu, Cezar. „Non-perturbative effects in string theory“. Palaiseau, Ecole polytechnique, 2010. http://pastel.archives-ouvertes.fr/docs/00/56/57/62/PDF/Phd-thesis.pdf.

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On étudie les effets non-perturbatifs généré par des branes instantoniques Euclidiens en compactifications de la théorie des cordes de type I/II avec orientifolds et D-branes magnétisées. Le focus est sur les instantons qui peuvent générer des corrections au superpotentiel. Une condition nécessaire est que les instantons doivent enrouler des cycles rigides. On considère la compactification de la théorie de Type I (IIB) sur l'orientifold T^6/Z_2xZ_2 avec torsion discrète et D-branes magnétisées. Les instantons enroulant le même cycle que l'O-plane exotique (requis par la torsion discrète) ont la structure désiré de modes zéro pour générer des corrections au superpotentiel. On construit des modèles globales basée sur cet orientifold ou les instantons génère des termes linaires et de termes de masse dans le superpotentiel. En théorie des cordes on calcule un couplage physique duquel on doit extraire la partie olomorphique pour obtenir le superpotentiel non-perturbatif. Les facteurs non-olomorphiques sont absorbés dans le potentiel de Kähler et dans redéfinitions des champs chiraux et modules des cordes fermées. On a dérivé ces redéfinitions pour les compactifications toroïdales (avec orientifolds) de la théorie de Type I avec branes magnétisées et lignes Wilson. Finalement, on a considéré des modèles globales avec des termes linéaires. On a calculé explicitement le superpotentiel non-perturbatif pour les orientifolds toroïdales. On a montré comment faire la somme sur les contributions a un instanton. Les modèles analysées possédaient des vides non-perturbatifs supersymétriques ou le group de jauge était brisé et certains modules des cordes ouvertes étaient stabilisés
We study non-perturbative effects generated by Euclidean brane instantons in compactifications of Type I/II string theory with orientifolds and magnetized D-branes. The focus is on instantons which can generate corrections to the superpotential. A necessary condition is that the instantons have to wrap rigid cycles. We consider the compactification of Type I (IIB) on the T^6/Z_2xZ_2 orientifold with discrete torsion and magnetized branes. The instantons wrapping the same cycle as the exotic O-planes (required by the presence of discrete torsion) have the desired uncharged zero-mode structure in order to generate corrections to the superpotential. We build global models based on this orientifold where stringy instantons generate linear terms and mass terms in the superpotential. Typically, in string theory one computes a physical coupling from which one has to extract a holomorphic part in order to obtain the non-perturbative superpotential. Various non-holomorphic factors are absorbed into the Kähler potential and redefinitions of chiral fields and closed string moduli. We have derived these redefinitions in the context of toroidal (orientifold) compactifications of Type I with magnetized branes and continuous Wilson lines. Finally, we have considered global models with linear terms in the superpotential generated non-perturbatively. We have computed explicitly the non-perturbative superpotential for toroidal orientifolds. We show how to sum coherently over the various one-instanton contributions. The explicit models analyzed possessed a non-perturbative supersymmetric vacuum where the gauge group was broken and certain open-string moduli were stabilized

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39

百武, 慶文. „Dielectric効果およびMyers効果によるD-branesの解析“. 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149971.

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40

Condeescu, Cezar. „Effets Non-perturbatifs en Théorie des Cordes“. Phd thesis, Ecole Polytechnique X, 2010. http://pastel.archives-ouvertes.fr/pastel-00565762.

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On étude les effets non-perturbatifs généré par des branes instantoniques Euclidiens en compactifications de la théorie des cordes de type I/II avec orientifolds et D-branes magnétisées. Le focus est sur les instantons qui peuvent générer des corrections au superpotentiel. Une condition nécessaire est que les instantons doivent enrouler des cycles rigides. On considère la compactification de la théorie de Type I (IIB) sur l'orientifold T^6/Z_2xZ_2 avec torsion discrète et D-branes magnétisées. Les instantons enroulant le même cycle que l'O-plane exotique (requis par la torsion discrète) ont la structure désiré de modes zéro pour générer des corrections au superpotentiel. On construit des modèles globales basée sur cet orientifold ou les instantons génère des termes linaires et de termes de masse dans le superpotentiel. En théorie des cordes on calcule un couplage physique duquel on doit extraire la partie olomorphique pour obtenir le superpotentiel non-perturbatif. Les facteurs non-olomorphiques sont absorbés dans le potentiel de Kähler et dans redéfinitions des champs chiraux et modules des cordes fermées. On a dérivé ces redéfinitions pour les compactifications toroïdales (avec orientifolds) de la théorie de Type I avec branes magnétisées et lignes Wilson. Finalement, on a considéré des modèles globales avec des termes linéaires. On a calculé explicitement le superpotentiel non-perturbatif pour les orientifolds toroïdales. On a montré comment faire la somme sur les contributions a un instanton. Les modèles analysées possédaient des vides non-perturbatifs supersymétriques ou le group de jauge était brisé et certains modules des cordes ouvertes étaient stabilisés.

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41

Benichou, Raphaël. „Supercordes, théories conformes et dualité holographique“. Paris 6, 2009. https://tel.archives-ouvertes.fr/tel-00392687.

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Cette thèse se consacre à l'étude de la théorie des cordes, en utilisant une description exacte en termes de théories conformes bidimensionnelles. Dans une première partie, nous considérons une famille de solutions exactes de la théorie des cordes appelées modèles de Gepner non-compacts. Nous avons étudié le spectre des cordes fermées et ouvertes dans ces modèles, en mettant l'accent sur les états localisés. Dans une deuxième partie, nous étudions la quantification de la corde en présence de champs Ramond-Ramond. Nous avons généralisé la procédure de Buscher pour obtenir les règles de T-dualité à partir du formalisme des spineurs purs. Nous avons enfin construit l'algèbre des courants quantiques dans les modèles sigma sur des variétés de super-groupes.

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42

Benichou, Raphael. „Supercordes, théories conformes et dualité holographique“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2009. http://tel.archives-ouvertes.fr/tel-00392687.

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Cette thèse se consacre à l'étude de la théorie des cordes en utilisant les outils des théories conformes bidimensionnelles. Dans la première partie, une famille de solutions non-compactes et courbes est etudiées : les modèles de Gepner non-compacts. Dans la deuxième partie, on se concentre sur des problèmes liés à la quantification de la corde en présence de flux RR.

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43

Choi, Jaewang. „Deformation of N=4 SYM with space-time dependent couplings“. Kyoto University, 2018. http://hdl.handle.net/2433/232239.

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44

Braun, Volker Friedrich. „K-theory and exceptional holonomy in string theory“. Doctoral thesis, [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965401650.

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45

Israel, Dan. „Supercordes en espace-temps courbe et theories conformes“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00007152.

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Cette these est consacree a l'etude des theories de supercordes dans les espaces-temps courbes. Nous etudions en particulier l'espace des modules des solutions de NS5-branes et de cordes fondamentales, a l'aide des techniques de deformations marginales de theories conformes. Parmi les exemples etudies se trouvent les espaces-temps anti-de Sitter a trois ou deux dimensions, differentes limites de decouplage de la theorie des petites cordes et l'univers de Goedel. Nous etudions egalement les fonctions de partitions de ces theories conformes, ainsi que les D-branes de certaines d'entre elles. Les applications holographiques potentielles de ces theories sont soulignees.

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46

Stiffler, Kory M. „A walk through superstring theory with an application to Yang-Mills theory: k-strings and D-branes as gauge/gravity dual objects“. Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/744.

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Superstring theory is one current, promising attempt at unifying gravity with the other three known forces: the electromagnetic force, and the weak and strong nuclear forces. Though this is still a work in progress, much effort has been put forth toward this goal. A set of specific tools which are used are gauge/gravity dualities. This thesis consists of a specific implementation of gauge/gravity dualities to describe k-strings of strongly coupled gauge theories as objects dual to Dpbranes embedded in confining supergravity backgrounds from low energy superstring field theory. Along with superstring theory, k-strings are also commonly investigated with lattice gauge theory and Hamiltonian methods. A k$string is a colorless combination of quark-anti-quark source pairs, between which a color flux tube develops. The two most notable terms of the k-string energy are, for large quark anti-quark separation L, the tension term, proportional to L, and the Coulombic 1/L correction, known as the Luscher term. This thesis provides an overview of superstring theories and how gauge/gravity dualities emerge from them. It shows in detail how these dualities can be used for the specific problem of calculating the k-string energy in 2+1 and 3+1 space-time dimensions as the energy of Dp-branes in the dual gravitational theory. A detailed review of k-string tension calculations is given where good agreement is found with lattice gauge theory and Hamiltonian methods. In reviewing the k-string tension, we also touch on how different representations of k-strings can be described with Dp-branes through gauge/gravity dualities. The main result of this thesis is how the Luscher term is found to emerge from the energy calculation of Dp-branes. In 2+1 space-time dimensions, we have Luscher term data to compare with from lattice gauge theory, where we find good agreement.

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47

Görlich, Lars. „N = 1 and non-supersymmetric open string theories in six and four space-time dimensions“. Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2003. http://dx.doi.org/10.18452/14978.

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Die vorliegende Arbeit beinhaltet ein einführendes Kapitel über Orbifold-Konstruktionen in dem neben rudimentären Grundlagen bereits speziellere Themen wie Diskrete Torsion und asymmetrische Orbifold-Gruppen behandelt werden. Als Beispiele für Orbifolde werden Kompaktifizierungen auf Tori sowie das asymmetrische T^4/Z(3)^L x Z(3)^R Orbifold behandelt. Danach wird eine allgemein gehaltene Einführung in Orientifolde gegeben, einschließlich des offenen String Sektors samt Chan-Paton Freiheitsgraden. Die darauf folgenden Kapitel 4-7 behandeln von mir durchgeführte Forschungsarbeiten. Kapitel 4 beschäftigt sich mit der Quantisierung des offenen Strings mit linearen Randbedingungen, wie sie bei Strings in elektro-magnetischen Feldern auftreten. Weiterhin wird die Quantisierung der Null- und Impuls-Moden des offenen Strings in Torus-Kompaktifizierungen durchgeführt. Außerdem wird für den Fall allgemeiner konstanter Hintergrund Neveu-Schwarz U(1)-Hintergrundfelder der Kommutator der Stringkoordinaten berechnet. Dieser stützt bisherige Resultate zur Nicht-Kommutativität von offenen Stringtheorien in Neveu-Schwarz Hintergründen. Kapitel 5 gibt, zusammen mit einigen neuen Erkenntnissen, Resultate von [1] über asymmetrische Orientifolde, insbesondere deren D-Branen Inhalt wieder. Kapitel 6 faßt die Veröffentlichung [2] zusammen, in der untersucht wurde, inwieweit sich phänomenolgisch interessante Modelle in Orientifolden von Torus-Kompaktifizierungen finden lassen. Insbesondere tragen die D9-Branen magnetische Flüsse, womit chirale Fermionen im Spektrum auftreten. Die Rechnungen werden größtenteils im gleichwertigen, T-dualen Bild ausgeführt. In diesem ist die Anzahl der chiralen Fermionen durch die topologische Schnittzahl der D-Branen gegeben. Existieren auf Torus-Kompaktifizierungen entweder nur nicht-chirale oder nicht-supersymmetrische Modelle, so lassen sich auf gewissen Orbifolden beide Eigenschaften miteinander vereinbaren. Kapitel 7 behandelt das "sigma Omega"-Orientifold auf einem T^6/Z(4) Orbifold. Als besonders interessantes Beispiel wird ein supersymmetrisches U(4) x U(2)^3_L x U(2)^3_R Modell vorgestellt, daß durch Einschalten geeigneter Hintergrundfelder in der effektiven Niederenergie-Wirkung auf ein Modell gebrochen wird, daß dem MSSM (minimalem supersymmetrischen Standard Modell) sehr ähnlich ist. Dieses Kapitel basiert auf unserer Publikation [3]. Ferner ist der Arbeit ein Anhang beigefügt, der einige der verwendeten Formeln sowie Beweise zu zwei Sätzen enthält, die im Text verwendet wurden.
This thesis contains an introductory chapter on orbifolds. Besides rudimentary basics we discuss more advanced topics like discrete torsion and asymmetric orbifold groups. As examples we investigate torus compactifications and an asymmetric T^4/Z(3)^L x Z(3)^R orbifold. The following chapter explains the foundations of orientifolds, including open strings with Chan-Paton degrees of freedom. Chapters 4-7 present own research. In chapter 4 we quantize open strings with linear boundary conditions, as they show up in electro-magnetic fields. We quantize the zero- and momentum-modes for toroidal compactifications, too. As an application we calculate the commutator of the coordinate fields in the case of general constant Neveu-Schwarz U(1)-field strengths. Thereby we confirm previous results on non-commutativity of open string theories in Neveu-Schwarz backgrounds. Chapter 5 reviews the results of a former publication [1] on asymmetric orientifolds, supplemented by some recent insights in connection with the preceeding chapter. Chapter 6 is a summary of [2]. In this publication we investigated to what extend one can build phenomenologically interesting models from toroidal orientifolds. By turning on magnetic fluxes on D9-branes we induce chiral fermions. Most calculations are performed in an (equivalent) T-dual picture. Here the number of chiral fermions is given by the topological intersection number of D-branes. In orientifolds of toroidal compactifications one obtains either non-chiral or non-supersymmetric orientifold solutions. However both properties can be reconciled in orientifolds that are obtained from specific supersymmetric orbifold compactifications. In chapter 7 we present the "sigma Omega"-Orientifold on a T^6/Z(4) orbifold. As a very attractive example we investigate a supersymmetric U(4) x U(2)^3_L x U(2)^3_R model that is broken to an MSSM-like model by switching on suitable background fields in the low energy effective action. This chapter is based on our publication [3]. The thesis is supplemented by an appendix with formulas applied in the text, as well as proofs to two theorems that were used as well.

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48

Rajan, Peter. „Spin-offs from Stretching a Point : Strings, Branes and Higher Spin“. Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4521.

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49

EDALATI, AHMADSARAEI MOHAMMAD. „TOPICS IN SUPERSYMMETRIC GAUGE THEORIES AND THE GAUGE-GRAVITY DUALITY“. University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1184947984.

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50

Bertolini, Matteo. „BPS Black Holes Solutions in Supergravity and Superstring Theory“. Doctoral thesis, SISSA, 1999. http://hdl.handle.net/20.500.11767/4519.

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Dissertationen zum Thema „D-branes“

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