Syllabus for Physics 234B: String Theory II
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The Top Yukawa Coupling from 10D Supergravity with E8 × E8 Matter
hep-th/9804107 ITEP-98-11 The top Yukawa coupling from 10D supergravity with E E matter 8 × 8 K.Zyablyuk1 Institute of Theoretical and Experimental Physics, Moscow Abstract We consider the compactification of N=1, D=10 supergravity with E E Yang- 8 × 8 Mills matter to N=1, D=4 model with 3 generations. With help of embedding SU(5) → SO(10) E E we find the value of the top Yukawa coupling λ = 16πα =3 → 6 → 8 t GUT at the GUT scale. p 1 Introduction Although superstring theories have great success and today are the best candidates for a quantum theory unifying all interactions, they still do not predict any experimentally testable value, mostly because there is no unambiguous procedure of compactification of extra spatial dimensions. On the other hand, many phenomenological models based on the unification group SO(10) were constructed (for instance [1]). They describe quarks and leptons in representa- tions 161,162,163 and Higgses, responsible for SU(2) breaking, in 10. Basic assumption of these models is that there is only one Yukawa coupling 163 10 163 at the GUT scale, which gives masses of third generation. Masses of first two families· and· mixings are generated due to the interaction with additional superheavy ( MGUT ) states in 16 + 16, 45, 54. Such models explain generation mass hierarchy and allow∼ to express all Yukawa matrices, which well fit into experimentally observable pattern, in terms of few unknown parameters. Models of [1] are unlikely derivable from ”more fundamental” theory like supergrav- ity/string. Nevertheless, something similar can be constructed from D=10 supergravity coupled to E8 E8 matter, which is low-energy limit of heterotic string [2]. -
Introduction to Conformal Field Theory and String
SLAC-PUB-5149 December 1989 m INTRODUCTION TO CONFORMAL FIELD THEORY AND STRING THEORY* Lance J. Dixon Stanford Linear Accelerator Center Stanford University Stanford, CA 94309 ABSTRACT I give an elementary introduction to conformal field theory and its applications to string theory. I. INTRODUCTION: These lectures are meant to provide a brief introduction to conformal field -theory (CFT) and string theory for those with no prior exposure to the subjects. There are many excellent reviews already available (or almost available), and most of these go in to much more detail than I will be able to here. Those reviews con- centrating on the CFT side of the subject include refs. 1,2,3,4; those emphasizing string theory include refs. 5,6,7,8,9,10,11,12,13 I will start with a little pre-history of string theory to help motivate the sub- ject. In the 1960’s it was noticed that certain properties of the hadronic spectrum - squared masses for resonances that rose linearly with the angular momentum - resembled the excitations of a massless, relativistic string.14 Such a string is char- *Work supported in by the Department of Energy, contract DE-AC03-76SF00515. Lectures presented at the Theoretical Advanced Study Institute In Elementary Particle Physics, Boulder, Colorado, June 4-30,1989 acterized by just one energy (or length) scale,* namely the square root of the string tension T, which is the energy per unit length of a static, stretched string. For strings to describe the strong interactions fi should be of order 1 GeV. Although strings provided a qualitative understanding of much hadronic physics (and are still useful today for describing hadronic spectra 15 and fragmentation16), some features were hard to reconcile. -
Tachyon Condensation with B-Field
Oct 2006 KUNS-2042 Tachyon Condensation with B-field Takao Suyama 1 Department of Physics, Kyoto University, Kitashirakawa, Kyoto 606-8502, Japan arXiv:hep-th/0610127v2 13 Nov 2006 Abstract We discuss classical solutions of a graviton-dilaton-Bµν-tachyon system. Both constant tachyon so- lutions, including AdS3 solutions, and space-dependent tachyon solutions are investigated, and their possible implications to closed string tachyon condensation are argued. The stability issue of the AdS3 solutions is also discussed. 1e-mail address: [email protected] 1 1 Introduction Closed string tachyon condensation has been discussed recently [1][2]. However, the understanding of this phenomenon is still under progress, compared with the open string counterpart [3]. A reason for the difficulty would be the absence of a useful tool to investigate closed string tachyon condensation. It is desired that there would be a non-perturbative framework for this purpose. Closed string field theory was applied to the tachyon condensation in string theory on orbifolds, and preliminary results were obtained [4], but the analysis would be more complicated than that in the open string case. To make a modest step forward, a classical gravitational theory coupled to a tachyon was discussed as a leading order approximation to the closed string field theory [5][6][7][8]. In [5][7][8], a theory of graviton, dilaton and tachyon was discussed, and its classical time evolution was investigated. In this paper, we investigate a similar theory, with NS-NS B-field also taken into account. By the presence of the B-field, an AdS3 background is allowed as a classical solution, in addition to the well- known linear dilaton solution. -
Arxiv:1805.06347V1 [Hep-Th] 16 May 2018 Sa Rte O H Rvt Eerhfudto 08Awar 2018 Foundation Research Gravity the for Written Essay Result
Maximal supergravity and the quest for finiteness 1 2 3 Sudarshan Ananth† , Lars Brink∗ and Sucheta Majumdar† † Indian Institute of Science Education and Research Pune 411008, India ∗ Department of Physics, Chalmers University of Technology S-41296 G¨oteborg, Sweden and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences Nanyang Technological University, Singapore 637371 March 28, 2018 Abstract We show that N = 8 supergravity may possess an even larger symmetry than previously believed. Such an enhanced symmetry is needed to explain why this theory of gravity exhibits ultraviolet behavior reminiscent of the finite N = 4 Yang-Mills theory. We describe a series of three steps that leads us to this result. arXiv:1805.06347v1 [hep-th] 16 May 2018 Essay written for the Gravity Research Foundation 2018 Awards for Essays on Gravitation 1Corresponding author, [email protected] [email protected] [email protected] Quantum Field Theory describes three of the four fundamental forces in Nature with great precision. However, when attempts have been made to use it to describe the force of gravity, the resulting field theories, are without exception, ultraviolet divergent and non- renormalizable. One striking aspect of supersymmetry is that it greatly reduces the diver- gent nature of quantum field theories. Accordingly, supergravity theories have less severe ultraviolet divergences. Maximal supergravity in four dimensions, N = 8 supergravity [1], has the best ultraviolet properties of any field theory of gravity with two derivative couplings. Much of this can be traced back to its three symmetries: Poincar´esymmetry, maximal supersymmetry and an exceptional E7(7) symmetry. -
Introduction to String Theory A.N
Introduction to String Theory A.N. Schellekens Based on lectures given at the Radboud Universiteit, Nijmegen Last update 6 July 2016 [Word cloud by www.worldle.net] Contents 1 Current Problems in Particle Physics7 1.1 Problems of Quantum Gravity.........................9 1.2 String Diagrams................................. 11 2 Bosonic String Action 15 2.1 The Relativistic Point Particle......................... 15 2.2 The Nambu-Goto action............................ 16 2.3 The Free Boson Action............................. 16 2.4 World sheet versus Space-time......................... 18 2.5 Symmetries................................... 19 2.6 Conformal Gauge................................ 20 2.7 The Equations of Motion............................ 21 2.8 Conformal Invariance.............................. 22 3 String Spectra 24 3.1 Mode Expansion................................ 24 3.1.1 Closed Strings.............................. 24 3.1.2 Open String Boundary Conditions................... 25 3.1.3 Open String Mode Expansion..................... 26 3.1.4 Open versus Closed........................... 26 3.2 Quantization.................................. 26 3.3 Negative Norm States............................. 27 3.4 Constraints................................... 28 3.5 Mode Expansion of the Constraints...................... 28 3.6 The Virasoro Constraints............................ 29 3.7 Operator Ordering............................... 30 3.8 Commutators of Constraints.......................... 31 3.9 Computation of the Central Charge..................... -
S-Duality-And-M5-Mit
N . More on = 2 S-dualities and M5-branes .. Yuji Tachikawa based on works in collaboration with L. F. Alday, B. Wecht, F. Benini, S. Benvenuti, D. Gaiotto November 2009 Yuji Tachikawa (IAS) November 2009 1 / 47 Contents 1. Introduction 2. S-dualities 3. A few words on TN 4. 4d CFT vs 2d CFT Yuji Tachikawa (IAS) November 2009 2 / 47 Montonen-Olive duality • N = 4 SU(N) SYM at coupling τ = θ=(2π) + (4πi)=g2 equivalent to the same theory coupling τ 0 = −1/τ • One way to ‘understand’ it: start from 6d N = (2; 0) theory, i.e. the theory on N M5-branes, put on a torus −1/τ τ 0 1 0 1 • Low energy physics depends only on the complex structure S-duality! Yuji Tachikawa (IAS) November 2009 3 / 47 S-dualities in N = 2 theories • You can wrap N M5-branes on a more general Riemann surface, possibly with punctures, to get N = 2 superconformal field theories • Different limits of the shape of the Riemann surface gives different weakly-coupled descriptions, giving S-dualities among them • Anticipated by [Witten,9703166], but not well-appreciated until [Gaiotto,0904.2715] Yuji Tachikawa (IAS) November 2009 4 / 47 Contents 1. Introduction 2. S-dualities 3. A few words on TN 4. 4d CFT vs 2d CFT Yuji Tachikawa (IAS) November 2009 5 / 47 Contents 1. Introduction 2. S-dualities 3. A few words on TN 4. 4d CFT vs 2d CFT Yuji Tachikawa (IAS) November 2009 6 / 47 S-duality in N = 2 . SU(2) with Nf = 4 . -
Achievements, Progress and Open Questions in String Field Theory Strings 2021 ICTP-SAIFR, S˜Ao Paulo June 22, 2021
Achievements, Progress and Open Questions in String Field Theory Strings 2021 ICTP-SAIFR, S˜ao Paulo June 22, 2021 Yuji Okawa and Barton Zwiebach 1 Achievements We consider here instances where string field theory provided the answer to physical open questions. • Tachyon condensation, tachyon vacuum, tachyon conjectures The tachyon conjectures (Sen, 1999) posited that: (a) The tachyon potential has a locally stable minimum, whose energy density measured with respect to that of the unstable critical point, equals minus the tension of the D25-brane (b) Lower-dimensional D-branes are solitonic solutions of the string theory on the back- ground of a D25-brane. (c) The locally stable vacuum of the system is the closed string vac- uum; it has no open string excitations exist. Work in SFT established these conjectures by finding the tachyon vac- uum, first numerically, and then analytically (Schnabl, 2005). These are non-perturbative results. 2 • String field theory is the first complete definition of string pertur- bation theory. The first-quantized world-sheet formulation of string theory does not define string perturbation theory completely: – No systematic way of dealing with IR divergences. – No systematic way of dealing with S-matrix elements for states that undergo mass renormalization. Work of A. Sen and collaborators demonstrating this: (a) One loop-mass renormalization of unstable particles in critical string theories. (b) Fixing ambiguities in two-dimensional string theory: For the one- instanton contribution to N-point scattering amplitudes there are four undetermined constants (Balthazar, Rodriguez, Yin, 2019). Two of them have been fixed with SFT (Sen 2020) (c) Fixing the normalization of Type IIB D-instanton amplitudes (Sen, 2021). -
Chapter 9: the 'Emergence' of Spacetime in String Theory
Chapter 9: The `emergence' of spacetime in string theory Nick Huggett and Christian W¨uthrich∗ May 21, 2020 Contents 1 Deriving general relativity 2 2 Whence spacetime? 9 3 Whence where? 12 3.1 The worldsheet interpretation . 13 3.2 T-duality and scattering . 14 3.3 Scattering and local topology . 18 4 Whence the metric? 20 4.1 `Background independence' . 21 4.2 Is there a Minkowski background? . 24 4.3 Why split the full metric? . 27 4.4 T-duality . 29 5 Quantum field theoretic considerations 29 5.1 The graviton concept . 30 5.2 Graviton coherent states . 32 5.3 GR from QFT . 34 ∗This is a chapter of the planned monograph Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity, co-authored by Nick Huggett and Christian W¨uthrich and under contract with Oxford University Press. More information at www.beyondspacetime.net. The primary author of this chapter is Nick Huggett ([email protected]). This work was sup- ported financially by the ACLS and the John Templeton Foundation (the views expressed are those of the authors not necessarily those of the sponsors). We want to thank Tushar Menon and James Read for exceptionally careful comments on a draft this chapter. We are also grateful to Niels Linnemann for some helpful feedback. 1 6 Conclusions 35 This chapter builds on the results of the previous two to investigate the extent to which spacetime might be said to `emerge' in perturbative string the- ory. Our starting point is the string theoretic derivation of general relativity explained in depth in the previous chapter, and reviewed in x1 below (so that the philosophical conclusions of this chapter can be understood by those who are less concerned with formal detail, and so skip the previous one). -
String Field Theory, Nucl
1 String field theory W. TAYLOR MIT, Stanford University SU-ITP-06/14 MIT-CTP-3747 hep-th/0605202 Abstract This elementary introduction to string field theory highlights the fea- tures and the limitations of this approach to quantum gravity as it is currently understood. String field theory is a formulation of string the- ory as a field theory in space-time with an infinite number of massive fields. Although existing constructions of string field theory require ex- panding around a fixed choice of space-time background, the theory is in principle background-independent, in the sense that different back- grounds 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 involv- ing 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 arXiv:hep-th/0605202v2 28 Jun 2006 in string theory. 1.1 Introduction In the early days of the subject, string theory was understood only as a perturbative theory. The theory arose from the study of S-matrices and was conceived of as a new class of theory describing perturbative interactions of massless particles including the gravitational quanta, as well as an infinite family of massive particles associated with excited string states. In string theory, instead of the one-dimensional world line 1 2 W. Taylor of a pointlike particle tracing out a path through space-time, a two- dimensional surface describes the trajectory of an oscillating loop of string, which appears pointlike only to an observer much larger than the string. -
Exceptional Field Theory and Supergravity Arnaud Baguet
Exceptional Field Theory and Supergravity Arnaud Baguet To cite this version: Arnaud Baguet. Exceptional Field Theory and Supergravity. High Energy Physics - Experiment [hep-ex]. Université de Lyon, 2017. English. NNT : 2017LYSEN022. tel-01563063 HAL Id: tel-01563063 https://tel.archives-ouvertes.fr/tel-01563063 Submitted on 17 Jul 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Numéro National de Thèse : 2017LYSEN022 Thèse de Doctorat de l’Université de Lyon opérée par l’École Normale Supérieure de Lyon École Doctorale 52 École Doctorale de Physique et d’Astrophysique de Lyon Soutenue publiquement le 30/06/2017, par : Arnaud Baguet Exceptional Field Theory and Supergravity - Théorie des Champs Exceptionnels et Supergravité Devant le jury composé de : Martin Cederwall Chalmers University of Technology Rapporteur François Delduc École Normale Supérieure de Lyon Examinateur Axel Kleinschmidt Max Planck Institute Postdam Rapporteur Michela Petrini Université Pierre et Marie Curie Examinatrice Henning Samtleben École Normale Supérieure de Lyon Directeur Contents 1 Introduction 9 1.1 String theory, dualities and supergravity . 11 1.2 The bosonic string . 13 1.3 Compactification and T-duality . 18 1.4 Double Field Theory . 21 1.5 Exceptional Field Theory . -
String Theory and the Ads/CFT Correspondence
String Theory and the AdS/CFT correspondence Matthias Gaberdiel ETH Zürich PSI 26 September 2019 Generalities What string theory is (and what it is not)? It is a promising approach towards a quantum theory incorporating high energy physics and general relativity. However, it is not a `complete’ theory: there are many conceptual problems (in particular its off-shell formulation) that are not well understood. Generalities What string theory is (and what it is not)? There are also (mainly technical) problems in understanding string theory for time-dependent and cosmological configurations, in particular for de Sitter backgrounds. On the other hand, string theory seems to provide, for example, a convincing explanation of black hole entropy in terms of microscopic states (at least for certain black holes). Generalities What string theory is (and what it is not)? String theory makes very specific and testable predictions… However, as for any theory of quantum gravity, these predictions are only `sharp’ near the Planck scale, and direct experimental verification seems currently out of reach. Generalities As a consequence, supporting evidence for string theory has appeared more indirectly, e.g. ‣ AdS/CFT correspondence has led to testable insights into conventional QFTs ‣ Triggered new developments in mathematics, e.g. mirror symmetry. ‣ Inspiration for model building, e.g. higher dimensions, supersymmetry, etc. ‣ Given rise to new techniques for perturbative and non-perturbative analysis of (susy) QFTs, e.g. Seiberg-Witten, etc. Generalities As a consequence, supporting evidence for string theory has appeared more indirectly, e.g. ‣ AdS/CFT correspondence has led to testable insights into conventional QFTs ‣ Triggered new developments in mathematics, e.g. -
E 8 in N= 8 Supergravity in Four Dimensions
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Chalmers Research E 8 in N= 8 supergravity in four dimensions Downloaded from: https://research.chalmers.se, 2019-05-11 18:56 UTC Citation for the original published paper (version of record): Ananth, S., Brink, L., Majumdar, S. (2018) E 8 in N= 8 supergravity in four dimensions Journal of High Energy Physics, 2018(1) http://dx.doi.org/10.1007/JHEP01(2018)024 N.B. When citing this work, cite the original published paper. research.chalmers.se offers the possibility of retrieving research publications produced at Chalmers University of Technology. It covers all kind of research output: articles, dissertations, conference papers, reports etc. since 2004. research.chalmers.se is administrated and maintained by Chalmers Library (article starts on next page) Published for SISSA by Springer Received: November 30, 2017 Accepted: December 23, 2017 Published: January 8, 2018 E8 in N = 8 supergravity in four dimensions Sudarshan Ananth,a Lars Brinkb,c and Sucheta Majumdara aIndian Institute of Science Education and Research, Pune 411008, India bDepartment of Physics, Chalmers University of Technology, S-41296 G¨oteborg, Sweden cDivision of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore E-mail: [email protected], [email protected], [email protected] Abstract: We argue that = 8 supergravity in four dimensions exhibits an exceptional N E8(8) symmetry, enhanced from the known E7(7) invariance. Our procedure to demonstrate this involves dimensional reduction of the = 8 theory to d = 3, a field redefinition to N render the E8(8) invariance manifest, followed by dimensional oxidation back to d = 4.