狄拉克費米子體系中的手征相變.pdf

1、中國科學技術大學博士學位論文狄拉克費米子體系中的手征相變姓名：李偉申請學位級別：博士專業(yè)：理論物理指導教師：程耕劉國柱20100401ABSTRACTABSTRACTHightemperaturesuperconductor(HTSC)andgraphenearetwostronglycorrelatedelectronsystemsthosehaveattractedgreatresearchinterestsinrecentyear

2、sTheyshareonecommonfeaturethatthelowenergyelementaryexcitationsaremasslessDiracfermions，arisingfromthespecialbandstructuresTheseDiracfermionssatisfyrelativisticDiracwaveequationandcanbedescribedbythree—dimensionalquantum

3、fieldtheoryThedynamicalchiralsymmetrybreakingcausedbygaugefieldandCoulombinteraction，whichcandescribethelow—energyphysicsofhightempera—turesuperconductorandgraphenerespectivelyThetheorydescribingthelow—energyphysicsofofH

4、TSCis(21)一dimensionQED(QEDa)，whilethatisCoulombinteractionfortheDiracfermionsingrapheneThedynamicchiralsymmetrybreaking(DCSB)inQEDahasbeeninvestigatedintensivelyformorethantwentyyearsandaboutdecadeforthatingraphene，Onthe

5、onehand，theseinvestigationsmayhelptOgaindeeperunderstandingofDCSBinQCDOntheotherhand，thisnon—perturbativephenomenoncanbewidelyusedtounderstandmanyimportantphysicalphenomenainHTSCandgrapheneInthisthesis，thechiralquantumph

6、asetransitionandtheconsequenteffectsonlow—energyphysicsofsystemarestudiedbydiscussingontheDCSBdrivenbygaugefieldandCoulombinteractioninHTSCandgraphene，respectivelyTheDCSBisrealizedbyformingfermion—anti—fcrmionpairsmediat

7、edbystronggauge(Coulomb)interactionResearchshowsthatwhentheinteractionbetweenDiracfermionsisstrongenough，theDiracfermionswillacquirefinitedynamicmassbyvacuumcondensationsandbreaktheoriginalchiralsymmetrycontemporarilyThr

8、oughthetheoreticalanal。ysisandcalculationoftheDyson—Schwinger(DS)equation，wehaveidentifiedtheconditionsoftheoccurrenceofDCSBintheHTSCandthegraphene，pointedoutthatthelong—rangenatureofgauge(Coulomb)interactionplayakeyrole