苏汝铿高等量子力学讲义.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Chapter 2Many Body Problem,2.1,Second quantization,The identical particles cannot be distinguished,2.1,Second quantization,The essence of the identical principle is that the state of a system should be described in terms of the particle number in a certain quantum state and the many-body problem should be discussed in the particle number representation instead of the original coordinate representation,2.1,Second quantization,We need to introduce the creation and the annihilation operators to deal with various problem in the many-body system,2.1,Second quantization,Bose system,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,Discussions,The wave function is already symmetric,n,k,is the particle number operator of k state,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.1,Second quantizationFor Fermions,2.1,Second quantization,2.1,Second quantization,2.1,Second quantization,2.2,Hartree,-Fork mean field approximation,Key:two-body problem,“one-body problem”+“mean field”,Example:Free electron gas in the metal,2.2,Hartree,-Fork mean field approximation,Screening Coulomb potential,Positive charge background cancels k=0 part,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,Spin effect,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.2,Hartree,-Fork mean field approximation,2.3,Superconductive theory,Experimental results,1908,K.Onnes,Liquid helium,1911,Hg:,Tc,=4.2K,1933,Meissner,effect B=0,1986Muller,Bednorz,High,Tc,Heat capacity Cs exp(-/,k,B,T,)energy gap,Isotropic effect,Tc,M1/2=const.,2.3,Superconductive theory,Frohlisch,Hamiltonian:,e-p-e,interaction,e-e,attraction,Cooper pair:,BCS Theory(,Variational,method),Variational,wave function,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,Bogoliubov-Valatin,canonical transformation,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,Energy gap equation,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,2.3,Superconductive theory,Stable state,2.4,Landau phase transition theory,Ehrenfest,equation,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory2.4,Landau phase transition theory,Van,Laue,criticism,Can 2,nd,order phase transition exist?,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,Landau theory,Introducing“order parameter ”,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,min,stable,max,instalble,phase transition point,2.4,Landau phase transition theory,real,stable,img,forbidden,A 0,2.4,Landau phase transition theory,Landau theory,Ehrenfest,equation,24,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.4,Landau phase transition theory,2.5,Superfluidity,theory,Landau,superfluidity,theory,New idea:elementary excitation,2.5,Superfluidity,theory,Experiments:,Superfluidity,10-510-4 cm(,0,),Mendelson,effect,-point,2.5,Superfluidity,theory,2.5,Superfluidity,theory,Landau theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,Bogoliubov,approximate second-quantization method,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,2.5,Superfluidity,theory,