简介:ThemagneticpropertiesofCeRhln5arestudiedbyfirst-principlescalculation.Spin-orbitcouplingisconsideredaswellasdifferentcorrectionsincludinglocaldensityapproximationpluson-siteCoulombinteractionU(U=1,1.5,3eV)andorbitalpolarization.TheresultsshowtheexistenceofonlymoderatecorrelationinCeRhln5andCe-4felectronsareontheborderoflocalizationanditinerancy.Theeffectofpressurebychangingthevolumeoftheunitcellisalsostudied.
简介:Ingraphene,conductanceelectronsbehaveasmasslessrelativisticparticlesandobeyananalogueoftheDiracequationintwodimensionswithachiralnature.Forthisreason,theboundingofelectronsingrapheneintheformofgeometriesofquantumdotsisimpossible.Ingaplessgraphene,duetoitsuniqueelectronicbandstructure,thereisaminimalconductivityatDiracpoints,thatis,inthelimitofzerodoping.Thiscreatesaproblemforusingsuchahighlymotivatednewmaterialinelectronicdevices.Oneofthewaystoovercomethisproblemisthecreationofabandgapinthegraphenebandstructure,whichismadebyinversionsymmetrybreaking(symmetryofsublattices).WeinvestigatetheconfinedstatesofthemasslessDiracfermionsinanimpuredgraphenebytheshort-rangeperturbationsfor"localchemicalpotential"and"localgap".Thecalculatedenergyspectrumexhibitsquitedifferentfeatureswithandwithouttheperturbations.Acharacteristicequationforboundstates(BSs)hasbeenobtained.Itissurprisinglyfoundthattherelationbetweentheradialfunctionsofsublatticeswavefunctions,i.e.,f_m~+(r),g_m~+(r),andf_m~-(r),g_m~-(r),canbeestablishedbySO(2)group.
简介:我们与强壮的纺纱轨道的couplings在三维、二维的材料处于悦耳的拓扑的量状态考察我们的理论进展。在三维的系统,我们建议新悦耳的拓扑的绝缘体,拓扑的绝缘在说的基于铋的skutterudites能被外部种类导致。涉及拓扑的乐队倒置过程的orbitals是d-orbitals,和p轨道,不同于象双性人那样的典型拓扑的绝缘体<潜水艇class=“a-plus-plus”>2Se<潜水艇class=“a-plus-plus”>3和BiTeI,在仅仅p轨道涉及乐队倒置的地方,处理。由于大d电子的状态的存在,在我们的建议拓扑的绝缘体的电子相互作用在另外的常规拓扑的绝缘体是比那强壮得多的。在二维的系统,我们调查了3d-transition-metal-dopedsilicene。用一个分析模型和第一原则的Wannier插值,我们表明与象钒那样的金属能支撑的某些3d转变装饰的那silicene稳定的量异常霍尔效果。我们也预言量山谷霍尔效果和电子上悦耳的拓扑的状态能在精力乐队倒置发生的某些transition-metal-dopedsilicenes被认识到。这些调查结果提供拓扑的状态能任意地在被控制的现实主义的材料。
简介:Weexperimentallydemonstratethenonlinearinteractionbetweentwochirpedbroadbandsingle-photon-levelcoherentstates.EachchirpedcoherentstateisgeneratedinindependentfiberBragggratings.Theyaresimultaneouslycoupledintoahigh-efficiencynonlinearwaveguide,wheretheyareconvertedintoanarrowbandsinglephotonstatewithanewfrequencybytheprocessofsum-frequencygeneration(SFG).AhigherSFGefficiencyof1.06×10-7isrealized,andthisefficiencymayachieveheraldingentanglementatadistance.Thisalsomadeitpossibletorealizelong-distancequantumcommunication,suchasdevice-independentquantumkeydistribution,bydirectlyusingbroadbandsinglephotonswithoutfiltering.
简介:Theexistenceanduniquenessofpositivesteadystatesfortheage-structuredMSEIRepidemicmodelwithage-dependenttransmissioncoefficientisconsidered.Thresholdresultsfortheexistenceofendemicstatesareestablished;undercertainconditions,uniquenessisalsoshown.
简介:Wereportboundstatesofsolitonsfromaharmonicmode-lockedfiberlaserbasedonasolution-processedgraphenesaturableabsorber.Stablesolitonpairs,26.2psapart,aregeneratedwith720fsduration.Bysimplyincreasingthepumppower,thelasercanalsogenerateharmonicmode-lockingwithharmonicsuptothe26thorder(409.6MHzrepetitionrate).Thisisasimple,low-cost,all-fiber,versatilemultifunctionultrafastlaserthatcouldbeusedformanyapplications.
简介:AvirtualTaylorimpactofcellularmaterialsisanalyzedwithawavepropagationtechnique,i.e.theLagrangiananalysismethod,ofwhichthemainadvantageisthatnopre-assumedconstitutiverelationshipisrequired.Timehistoriesofparticlevelocity,localstrain,andstressprofilesarecalculatedtopresentthelocalstress–strainhistorycurves,fromwhichthedynamicstress–strainstatesareobtained.Thepresentresultsrevealthatthedynamic-rigid-plastichardening(D-R-PH)materialmodelintroducedinapreviousstudyofourgroupisingoodagreementwiththedynamicstress–strainstatesunderhighloadingratesobtainedbytheLagrangiananalysismethod.ItdirectlyreflectstheeffectivenessandfeasibilityoftheD-R-PHmaterialmodelforthecellularmaterialsunderhighloadingrates.
简介:Basedonthevariationaltheory,awavelet-basednumericalmethodisdevelopedtocalculatethedefectstatesofacousticwavesintwo-dimensionalphononiccrystalswithpointandlinedefects.Thesupercelltechniqueisapplied.Byexpandingthedisplacementfieldandthematerialconstants(massdensityandelasticstiffness)inperiodicwavelets,theexplicitformula-tionsofaneigenvalueproblemfortheplaneharmonicbulkwavesinsuchaphononicstructurearederived.Thepointandlinedefectstatesinsolid-liquidandsolid-solidsystemsarecalcu-lated.Comparisonsofthepresentresultswiththosemeasuredexperimentallyorthosefromtheplanewaveexpansionmethodshowthatthepresentmethodcanyieldaccurateresultswithfasterconvergenceandlesscomputingtime.
简介:Emission Temperatures from Populations of Particle Unstable States as a Function of Impact ParameterEmissionTemperaturesfromP...
简介:Weproposeanadiabatic-passageschemeforthegenerationofthree-qutritsingletstateswithtwo-leveltrappedions.Distinctlydifferentfrompreviousproposals,weencodequtritsinDickestateswithtwo-levelionsandusetheadiabatic-evolutiontechniquesinordernottoexactlycontrolthelaserpulses,makingtherealizationoftheschememucheasier.Furthermore,thephononisonlyvirtuallyexcitedintheprocedure,sotheeffectofthephononlossescanbereduced.
简介:AsimplemethodispresentedforgeneratingmulticomponentSchroedingercatstatesthroughresonantatomfieldinteractions.Intheschementwo-levelatoms,initiallyingroundstates,aresentthrougharesonantcavityfilledwithastrongcoherentfieldsequentially.Thenstate-selectivemeasurementsareperformedontheatoms.Thedetectionsoftheatomsingroundstatescollapsethecavityfieldontoasuperpositionof2^ncoherentstates.Thisisthefirstwayforproducingsuperpositionsofmanycoherentstatesthroughresonantatom-fieldinteraction.
简介:当界限状态由instantaneousBethe-Salpeter(BS)是描述得好的时,我们精确为在二个界限状态之间的转变导出“严密即时明确的表达”方程(即方程的核“偶尔”是即时的)。事实上,Theobtained严密即时明确的表达被表示为当减少的BS波浪工作出现在明确的表达时,“二个减少的BS波浪函数”适当地夹的一个操作符是即时BS方程的严密解决方案,并且他们可以正直地联系toSchroedinger波浪函数。我们也证明严密即时明确的表达关于U_(他们)(1)是计量器不变的转变精确,如果担心的转变是放射的。明确的表达的一些应用被构画出。
简介:Thescatteringmatrixtheoryhasbeendevelopedtocalculatethethird-ordernonlineareffectinsphere-grapheneslabstructures.Bydesigningstructuralparameters,wehavedemonstratedthattheincidentelectromagneticwavecanbewellconfinedinthegrapheneinthesestructuresduetotheformationofaboundstateinthecontinuum(BIC)ofradiationmodes.Basedonsuchaboundstate,third-harmonic(TH)generationandfour-wavemixing(FWM)havebeenstudied.ItisfoundthattheefficiencyofTHgenerationinmonolayergraphenecanbeenhancedabout7ordersofmagnitude.Itisinterestingthatwecandesignstructureparameterstomakeallbeams(thepumpbeam,probebeam,andgeneratedFWMsignal)beBICsatthesametime.Insuchacase,theefficiencyofFWMinmonolayergraphenecanbeenhancedabout9ordersofmagnitude.BoththeTHandFWMsignalsaresensitivetothewavelength,andpossesshighQfactors,whichexhibitverygoodmonochromaticity.BytakingsuitableBICs,theselectivegenerationofTHandFWMsignalsforS-andP-polarizedwavescanalsoberealized,whichisbeneficialforthedesignofopticaldevices.
简介:Theadsorptionandelectronicpropertiesofisolatedcobaltphthalocyanine(CoPc)moleculeonanultrathinlayerofNaClhavebeeninvestigated.High-resolutionSTMimagesgiveadetailedpictureofthelowestunoccupiedmolecularorbital(LUMO)ofanisolatedCoPc.ItisshownthattheNaClultrathinlayerefficientlydecouplestheinteractionofthemoleculesfromtheunderneathmetalsubstrate,whichmakesitanidealsubstrateforstudyingthepropertiesofsinglemolecules.Moreover,strongdependenceoftheappearanceofthemoleculesonthesamplebiasintheregionofrelativelyhighbias(>3.1V)isascribedtotheimagepotentialstates(IPSs)ofNaCl/Cu(100),whichmayprovideuswithapossiblemethodtofabricatequantumstoragedevices.
简介:Thefeaturesofthelow-lyingspectraoffour-bodyA+B-A+B-systemshavebeendeducedbasedonsymmetry.Usingthemethodoffew-bodyphysics,wecalculatetheenergyspectraofA+B-A+B-systemsinaharmonicquantumdot.Wefindthatthebiexcitoninatwo-dimensionalquantumdotmayhaveotherboundexcitedstatesandthequantummechanicalsymmetryplaysacrucialroleindeterminingtheenergylevelsandstructuresofthelow-lyingstates.