Lecture Notes in Physics 929 Badis Ydri Lectures on Matrix Field Theory Lecture Notes in Physics Volume 929 FoundingEditors W.Beiglböck J.Ehlers K.Hepp H.Weidenmüller EditorialBoard M.Bartelmann,Heidelberg,Germany B.-G.Englert,Singapore,Singapore P.HaRnggi,Augsburg,Germany M.Hjorth-Jensen,Oslo,Norway R.A.L.Jones,Sheffield,UK M.Lewenstein,Barcelona,Spain H.vonLoRhneysen,Karlsruhe,Germany J.-M.Raimond,Paris,France A.Rubio,Donostia,SanSebastian,Spain M.Salmhofer,Heidelberg,Germany W.Schleich,Ulm,Germany S.Theisen,Potsdam,Germany D.Vollhardt,Augsburg,Germany J.D.Wells,AnnArbor,USA G.P.Zank,Huntsville,USA The Lecture Notes in Physics The series Lecture Notes in Physics (LNP), founded in 1969, reports new devel- opmentsin physicsresearch and teaching-quicklyand informally,but with a high qualityand the explicitaim to summarizeand communicatecurrentknowledgein anaccessibleway.Bookspublishedinthisseriesareconceivedasbridgingmaterial between advanced graduate textbooks and the forefront of research and to serve threepurposes: (cid:129) to be a compact and modern up-to-date source of reference on a well-defined topic (cid:129) to serve as an accessible introduction to the field to postgraduate students and nonspecialistresearchersfromrelatedareas (cid:129) to be a source of advanced teaching material for specialized seminars, courses andschools Bothmonographsandmulti-authorvolumeswillbeconsideredforpublication. Editedvolumesshould,however,consistofaverylimitednumberofcontributions only.ProceedingswillnotbeconsideredforLNP. VolumespublishedinLNParedisseminatedbothinprintandinelectronicfor- mats,theelectronicarchivebeingavailableatspringerlink.com.Theseriescontent isindexed,abstractedandreferencedbymanyabstractingandinformationservices, bibliographicnetworks,subscriptionagencies,librarynetworks,andconsortia. Proposalsshouldbe sent to a memberof the EditorialBoard, ordirectly to the managingeditoratSpringer: ChristianCaron SpringerHeidelberg PhysicsEditorialDepartmentI Tiergartenstrasse17 69121Heidelberg/Germany [email protected] Moreinformationaboutthisseriesathttp://www.springer.com/series/5304 Badis Ydri Lectures on Matrix Field Theory 123 BadisYdri InstituteofPhysics BMAnnabaUniversity Annaba,Algeria ISSN0075-8450 ISSN1616-6361 (electronic) LectureNotesinPhysics ISBN978-3-319-46002-4 ISBN978-3-319-46003-1 (eBook) DOI10.1007/978-3-319-46003-1 LibraryofCongressControlNumber:2016959278 ©SpringerInternationalPublishingAG2017 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped. Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant protectivelawsandregulationsandthereforefreeforgeneraluse. Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthisbook arebelievedtobetrueandaccurateatthedateofpublication.Neitherthepublishernortheauthorsor theeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinorforany errorsoromissionsthatmayhavebeenmade. Printedonacid-freepaper ThisSpringerimprintispublishedbySpringerNature TheregisteredcompanyisSpringerInternationalPublishingAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland To myfatherforhiscontinuoussupport throughouthislife... SaadYdri 1943–2015 Alsoto my... Nour Preface The subject of matrix field theory involves matrix models, noncommutative geometry,fuzzyphysicsandnoncommutativefieldtheory,andtheirinterplay. These lecture notes contain a systematic construction of matrix models of quantum field theories with noncommutative and fuzzy geometries. Emphasis is placed on the matrix formulation of noncommutative and fuzzy spaces and on thenonperturbativetreatmentofthecorrespondingfieldtheories.Inparticular,the phase structure of noncommutative phi-four theory is treated in great detail, and an introduction to noncommutative gauge theory is given. The text has evolved partly from my own personalnotes on the subject and partly from lectures given, intermittently, to my doctoral students during the past few years. Thus, the list of topics, while not necessarily representing the exact state of the art, reflects the researchinterestsoftheauthorandtheeducationalgoalsofAnnabaUniversity. The references included are not meant to be comprehensiveor exhaustive, but theywillprovideasolidbibliographyandareliableguidetobackgroundreading. Small parts of these lectures have already appeared in various preprintson the arXiv.ReferencetothisSpringerpublicationismadethere. The bookisprimarilywrittenasa self-studyguideforpostgraduatestudents— with the aim of pedagogically introducing them to key analytical and numerical toolsaswellasusefulphysicalmodelsinapplications.Lastbutnotleast,Idedicate thisworktomyfatherSaadYdri,1943–2015,forhiscontinuoussupport. Annaba,Algeria BadisYdri July2016 vii Contents 1 IntroductoryRemarks ...................................................... 1 1.1 Noncommutativity,FuzzinessandMatrices........................... 1 1.2 NoncommutativityinQuantumMechanics ........................... 3 1.3 MatrixYang-MillsTheories............................................ 5 1.4 NoncommutativeScalarFieldTheory................................. 8 References..................................................................... 12 2 TheNoncommutativeMoyal-WeylSpacesRd ............................ 19 (cid:2) 2.1 HeisenbergAlgebraandCoherentStates.............................. 19 2.1.1 RepresentationsoftheHeisenberg-WeylAlgebra............ 19 2.1.2 CoherentStates................................................. 21 2.1.3 Symbols......................................................... 25 2.1.4 WeylSymbolandStarProducts............................... 30 2.2 NoncommutativityfromaStrongMagneticField .................... 36 2.3 NoncommutativeMoyal-WeylSpacetimes............................ 41 2.3.1 Algebra,WeylMap,DerivationandIntegral/Trace........... 41 2.3.2 StarProductandScalarAction................................ 46 2.3.3 TheLangmann-Szabo-ZaremboModels...................... 47 2.3.4 DualityTransformationsandMatrixRegularization ......... 52 2.3.5 TheGrosse-WulkenhaarModel ............................... 55 2.3.6 ASphereBasis ................................................. 58 2.4 OtherSpaces............................................................ 59 2.4.1 TheNoncommutative/FuzzyTorus............................ 59 2.4.2 TheFuzzyDiscofLizzi-Vitale-Zampini...................... 68 References..................................................................... 70 3 TheFuzzySphere............................................................ 73 3.1 QuantizationofS2...................................................... 73 3.1.1 TheAlgebraC1.S2/andtheCoadjointOrbit SU.2/=U.1/ .................................................... 73 3.1.2 TheSymplecticFormdcos(cid:2) ^d(cid:3) ........................... 75 3.1.3 QuantizationoftheSymplecticFormonS2 .................. 77 ix x Contents 3.2 CoherentStatesandStarProductonFuzzyS2 ....................... 80 N 3.3 TheFlatteningLimitofR2............................................. 88 (cid:2) 3.3.1 FuzzyStereographicProjection ............................... 88 3.3.2 CoherentStatesandPlanarLimit.............................. 91 3.3.3 TechnicalDigression........................................... 94 3.4 TheFuzzySphere:ASummary........................................ 96 3.5 FuzzyFieldsandActions .............................................. 103 3.5.1 ScalarActiononS2 ............................................ 103 N 3.5.2 ExtensiontoS2 (cid:2)S2 .......................................... 103 N N 2 3.6 IntroducingFuzzyCP ................................................. 106 3.7 FuzzyFermions......................................................... 108 3.7.1 ContinuumDiracOperators ................................... 109 3.7.2 FuzzyDiracOperators......................................... 112 References..................................................................... 117 4 QuantumNoncommutativePhi-Four...................................... 119 4.1 TheUV-IRMixing ..................................................... 119 4.2 TheStripePhase........................................................ 123 4.2.1 TheDisorderedPhase.......................................... 123 4.2.2 TheOrderedPhase............................................. 129 4.2.3 ThePhaseStructure:ALifshitzTriplePoint ................. 132 4.2.4 Stripesin2Dimension......................................... 137 4.3 TheSelf-DualNoncommutativePhi-Four............................. 149 4.3.1 IntegrabilityandExactSolution............................... 149 4.3.2 NonperturbativeUV-IRMixing ............................... 161 4.4 NoncommutativePhi-FourontheFuzzySphere...................... 163 4.4.1 ActionandLimits .............................................. 163 4.4.2 TheEffectiveActionandThe2-PointFunction.............. 164 4.4.3 The4-PointFunctionandNormalOrdering.................. 167 4.4.4 ThePhaseStructureandEffectivePotential.................. 169 4.4.5 FuzzyS2(cid:2)S2andPlanarLimit:FirstLook.................. 172 4.4.6 MoreScalarActionsonMoyal-WeylPlaneand FuzzySphere................................................... 176 4.5 MonteCarloSimulations............................................... 185 4.5.1 FuzzySphere:AlgorithmsandPhaseDiagram............... 185 4.5.2 FuzzyTorus:DispersionRelations............................ 190 4.6 InitiationtotheWilsonRenormalizationGroup...................... 191 4.6.1 TheWilson-FisherFixedPointinNCˆ4..................... 191 4.6.2 TheNoncommutativeO.N/Wilson-FisherFixedPoint...... 203 4.6.3 TheMatrixFixedPoint ........................................ 203 References..................................................................... 204 5 TheMultitraceApproach................................................... 207 5.1 PhaseStructureofFuzzyandNoncommutativeˆ4 .................. 207 5.2 NoncommutativePhi-FourRevisited.................................. 209 Contents xi 5.2.1 TheMoyal-WeylPlaneR2 ................................... 209 (cid:2);(cid:4) 5.2.2 TheFuzzySphereS2 ........................................ 211 N;(cid:4) 5.3 MultitraceApproachontheFuzzySphere............................ 213 5.4 TheRealQuarticMultitraceMatrixModelonR2 andS2 ....... 221 (cid:2);(cid:4) N;(cid:4) 5.4.1 Setup............................................................ 221 5.4.2 TheEffectiveMatrixAction................................... 226 5.5 MatrixModelSolution................................................. 236 5.5.1 Scaling.......................................................... 236 5.5.2 SaddlePointEquation.......................................... 239 5.6 TheRealQuarticMatrixModel ....................................... 242 5.6.1 FreeTheory..................................................... 243 5.6.2 TheSymmetricOne-Cut(Disordered)Phase................. 243 5.6.3 TheTwo-Cut(Non-uniform-Ordered)Phase ................. 246 5.6.4 TheAsymmetricOne-Cut(Uniform-Ordered)Phase ........ 249 5.7 MulticutSolutionsoftheMultitraceMatrixModel .................. 250 5.7.1 TheOne-CutPhase............................................. 250 5.7.2 TheTwo-CutPhase ............................................ 254 5.7.3 TheTriplePoint................................................ 255 5.8 ThePlanarTheory...................................................... 260 5.8.1 TheWignerSemicircleLaw................................... 260 5.8.2 IntroducingFuzzyProjectiveSpaces.......................... 264 5.8.3 FuzzyToriRevisited ........................................... 266 5.9 TheNon-perturbativeEffectivePotentialApproach.................. 269 References..................................................................... 273 6 NoncommutativeGaugeTheory ........................................... 277 6.1 GaugeTheoryonMoyal-WeylSpaces ................................ 277 6.2 RenormalizedPerturbationTheory.................................... 279 6.2.1 TheEffectiveActionandFeynmanRules .................... 279 6.2.2 VacuumPolarization........................................... 283 6.2.3 TheUV-IRMixingandTheBetaFunction................... 286 6.3 QuantumStability ...................................................... 289 6.3.1 EffectivePotential.............................................. 289 6.3.2 ImpactofSupersymmetry ..................................... 291 6.4 Initiationto NoncommutativeGaugeTheoryonthe FuzzySphere............................................................ 294 6.5 GaugeTheoryonTheNoncommutativeTorus........................ 299 6.5.1 TheNoncommutativeTorusTd Revisited..................... 299 (cid:2) 6.5.2 U.N/GaugeTheoryonTd .................................... 301 (cid:2) 6.5.3 TheWeyl-’tHooftSolution ................................... 302 6.5.4 SL.d;Z/Symmetry............................................. 305 6.5.5 MoritaEquivalence............................................. 307 References..................................................................... 312