Matrix Models of String Theory Matrix Models of String Theory Badis Ydri Annaba University, Annaba, Algeria IOP Publishing, Bristol, UK ªIOPPublishingLtd2018 Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem ortransmittedinanyformorbyanymeans,electronic,mechanical,photocopying,recording orotherwise,withoutthepriorpermissionofthepublisher,orasexpresslypermittedbylawor undertermsagreedwiththeappropriaterightsorganization.Multiplecopyingispermittedin accordancewiththetermsoflicencesissuedbytheCopyrightLicensingAgency,theCopyright ClearanceCentreandotherreproductionrightsorganizations. PermissiontomakeuseofIOPPublishingcontentotherthanassetoutabovemaybesought [email protected]. BadisYdrihasassertedhisrighttobeidentifiedastheauthorofthisworkinaccordancewith sections77and78oftheCopyright,DesignsandPatentsAct1988. ISBN 978-0-7503-1726-9(ebook) ISBN 978-0-7503-1724-5(print) ISBN 978-0-7503-1725-2(mobi) DOI 10.1088/978-0-7503-1726-9 Version:20181001 IOPExpandingPhysics ISSN2053-2563(online) ISSN2054-7315(print) BritishLibraryCataloguing-in-PublicationData:Acataloguerecordforthisbookisavailable fromtheBritishLibrary. PublishedbyIOPPublishing,whollyownedbyTheInstituteofPhysics,London IOPPublishing,TempleCircus,TempleWay,Bristol,BS16HG,UK USOffice:IOPPublishing,Inc.,190NorthIndependenceMallWest,Suite601,Philadelphia, PA19106,USA To my father for his continuous support throughout his life … Saad Ydri 1943–2015 Also to my … Nour Contents Author biography xiii 1 Introduction 1-1 References 1-4 Part I String theory 2 String theory 2-1 2.1 Actions, symmetries and solutions 2-1 2.1.1 Polyakov action 2-1 2.1.2 Boundary conditions and symmetries 2-3 2.1.3 Closed string solutions 2-5 2.1.4 Open string solutions 2-9 2.2 Canonical quantization and Virasoro algebra 2-10 2.2.1 Canonical quantization 2-10 2.2.2 Virasoro algebra 2-13 2.3 Spurious states and critical strings 2-17 2.3.1 Spurious states 2-17 2.3.2 Critical strings 2-19 2.4 Lightcone gauge quantization 2-20 2.4.1 Critical strings 2-20 2.4.2 Rigorous proof 2-23 2.4.3 Spectrum 2-23 2.5 Exercises 2-24 References 2-42 3 Polyakov path integral 3-1 3.1 Gauge fixing and Fadeev–Popov ghosts 3-1 3.2 The energy–momentum tensor 3-4 3.3 Quantization of the ghosts 3-7 3.3.1 The open string 3-7 3.3.2 The closed string 3-8 3.3.3 Virasoro generators 3-9 3.4 BRST symmetry 3-12 3.4.1 Gauge theory 3-12 3.4.2 General case 3-13 vii MatrixModelsofStringTheory 3.4.3 String theory 3-15 3.5 Exercises 3-22 References 3-22 4 Introduction to conformal field theory 4-1 4.1 The conformal groupsSO(p + 1, q + 1) 4-1 4.2 The conformal group in two dimensions 4-3 4.3 The energy–momentum tensor 4-6 4.4 The operator product expansion 4-8 4.5 Conformal field theory and BRST quantization 4-18 4.6 Representation theory of the Virasoro algebra 4-27 4.6.1 Virasoro algebra revisited 4-27 4.6.2 Overview of representation theory 4-28 4.7 Theorem 4-31 4.8 Exercises 4-32 References 4-35 5 Superstring theory essentials 5-1 5.1 The superparticle 5-1 5.1.1 Bosonic particle 5-1 5.1.2 The superparticle 5-2 5.1.3 Action 5-3 5.1.4 The κ-symmetry 5-5 5.2 The Green–Schwarz superstring 5-6 5.3 The Ramond–Neveu–Schwarz superstring 5-9 5.3.1 Supersymmetric action on the worldsheet 5-9 5.3.2 Energy–momentum tensor and supercurrent 5-10 5.3.3 Super-Virasoro constraints 5-14 5.3.4 Boundary conditions (Ramond and Neveu–Schwarz) 5-16 5.4 Canonical quantization 5-18 5.4.1 Commutation relations 5-18 5.4.2 Ramond (fermionic) and Neveu–Schwarz (bosonic) open string 5-20 sectors 5.4.3 Super-Virasoro algebra 5-23 5.5 The light cone/path integral quantization 5-25 5.5.1 The light cone quantization and critical dimension 5-25 5.5.2 The GSO conditions and superstring spectrum 5-26 5.6 Other very important topics 5-31 viii MatrixModelsofStringTheory 5.7 Exercises 5-31 References 5-34 Part II Matrix string theory 6 A lightning introduction to superstring theory and some 6-1 related topics 6.1 Quantum black holes 6-1 6.1.1 Schwarzschild black hole 6-2 6.1.2 Hawking temperature 6-2 6.1.3 Page curve and unitarity 6-5 6.1.4 Information loss problem 6-5 6.1.5 Thermodynamics 6-7 6.2 Some string theory and conformal field theory 6-7 6.2.1 The conformal anomaly 6-7 6.2.2 The operator product expansion 6-9 6.2.3 The bc CFT 6-12 6.2.4 The superconformal field theory 6-14 6.2.5 Vertex operators 6-14 6.2.6 Background fields 6-15 6.2.7 Beta function: finiteness and Weyl invariance 6-17 6.2.8 String perturbation expansions 6-19 6.2.9 Spectrum of type II string theory 6-20 6.3 On Dp-branes and T-duality 6-23 6.3.1 Introductory remarks 6-23 6.3.2 Coupling to abelian gauge fields 6-24 6.3.3 Symmetry under the exchange of momentum and winding 6-25 6.3.4 Symmetry under the exchange of Neumann and Dirichlet 6-27 6.3.5 Chan–Paton factors 6-28 6.3.6 Electromagnetism on a circle and Wislon lines 6-29 6.3.7 The D-branes on the dual circle 6-31 6.4 Quantum gravity in two dimensions 6-33 6.4.1 Dynamical triangulation 6-34 6.4.2 Matrix models of D = 0 string theory 6-35 6.4.3 Matrix models of D = 1 string theory 6-37 6.4.4 Preliminary synthesis 6-38 6.5 Exercise 6-39 References 6-39 ix