原子核集体激发的费米液体模型研究课件

NuclearCollectiveExcitationinaFemi-LiquidModelBao-XiSUNBeijingUniversityofTechnology2012.06.15KITPC,BeijingContentFermi-liquidModelbasedonLandauTheory.RelationbetweenisoscalargiantresonanceandisovectorgiantresonanceCollectiveexcitationinnuclearmatterCollectiveexcitationinfinitenucleiConclusionFermi-liquidModelbasedonLandauTheoryXiao-GangWen,Quantumfieldtheoryofmany-bodysystems,OxfordUniversityPress,Oxford,2004.Densityofquasi-nucleonsThequasi-nucleondensityneartheFermi-surface:withVibrationsofFermisurfaceLinearizedliquidequationofmotioninthemomentumspacewithandPotentialbetweennucleonsinthelinearWaleckamodelFermiliquidfunctionwithandFermienergyandFermivelocityThequasi-nucleondensitycanbeexpandedinsphericalharmonics:LiquidequationofmotioninsphericalharmonicsThestabilityoftheFermiliquidrequiresthediagonalmatrixelementsofMmustbepositivedefinite,andwecanwriteMasM=WWT.LettingandEigenvaluesoftheHamiltonianSincethenucleonnearFermi-surfaceiseasiertobeexcited,inthefollowingcalculation,wesetthevalueofnucleonmomentumCollectiveexcitationRelationbetweenisoscalarandisovectorgiantresonancesThenuclearisovectorgiantresonancescorrespondtothenuclearcollectiveexcitationthatthecollectiveexcitationofprotonsiscreatingwiththeenergyES(l),whilethecollectiveexcitationofneutronsisannihilatingwiththeenergyES(l),andviceversa.RelationbetweenisoscalarandisovectorgiantresonancesTheenergyofthenuclearisovectorgiantresonanceisabouttwiceofthecorrespondingisoscalargiantresonanceinthenuclearmatter,i.e.,GiantmonopoleresonancesoffinitenucleiL=0M*/ME0(p)E0(n)E0(p)+E0(n)ESEVPb2080.74216.287.0523.3314.17+-0.2826.0+-3.0Sm1440.74215.269.0024.2615.39+-0.28_Sn1160.74215.269.0024.2616.07+-0.12_Zr900.71717.5713.1330.717.89+-0.2028.5+-2.6Ca400.71715.5815.5831.1631.1+-2.2GiantdipoleresonancesoffinitenucleiTheisovectorgiantdipoleresonanceofthenucleusisashiftofthecenterofmass,whichcorrespondstothecreationoftheL=1collectiveexcitationofprotonsorneutrons.

Giantquadrupoleresonancesoffinitenucleil=2M*/ME0(p)E0(n)E0(p)+E0(n)ESEVPb2080.74215.025.8420.8610.9+-0.122.0Zr900.74213.168.2721.4314.41+-0.1_Ca400.6918.5418.5437.0817.8+-0.332.5+-1.5O160.6918.5418.5437.0820.7_MixtureofdifferentLstate

(M*/M=0.742,kF=1.36fm-1)ConclusionIntheFermi-liquidmodel,theexchangeinteractionbetweennucleonscausesthenuclearcollectiveexcitation.