Rayleigh 1894 / Schrödinger 1926 expansion for eigenvalues of H = H_0 + λV under the assumption that λV is a small perturbation of the known H_0 spectrum. Formal expansion: E_n = Σ_k λ^k E_n^(k), |n⟩ = Σ_k λ^k |n^(k)⟩. Order-by-order…
Rayleigh 1894 / Schrödinger 1926 expansion for eigenvalues of H = H_0 + λV under the assumption that λV is a small perturbation of the known H_0 spectrum. Formal expansion: E_n = Σ_k λ^k E_n^(k), |n⟩ = Σ_k λ^k |n^(k)⟩. Order-by-order…