Many Body Perturbation: Solutions and Corrections

This lecture covers the solutions and corrections in many-body perturbation theory, focusing on exactly solvable models and the calculation of coefficients for the first and second order corrections to the wavefunction and energy. It also explains the Møller-Plesset perturbation theory, detailing the unperturbed system, perturbation, and corrections to the energy and wavefunction. The instructor emphasizes the importance of normalization conditions and the impact of electron-electron repulsion in the calculations.