Send the following on WhatsApp
Continue to ChatSimplest perturbation two by two Hamiltonian https://peeterjoot.com/2015/12/07/simplest-perturbation-two-by-two-hamiltonian/
Simplest perturbation two by two Hamiltonian https://peeterjoot.com/2015/12/07/simplest-perturbation-two-by-two-hamiltonian/