MANY-BODY THEORY

Second quantization. Degenerate electron gas. Photons and phonons. Green functions at T = 0. Their analytical properties and Lehmann representation. Wick's theorem. Perturbation theory. Feynman diagrams. Self-energy. Dyson equation. Hartree-Fock approximation. Renormalization: concept of quasiparticle. Microscopical foundations of Landay theory of Fermi liquids. Polarizability and density-density correlation function. RPA. Interaction with an external potential.