Time-independent perturbation theory applied to a spin-1/2 particle

Abstract

This review examines the application of the first-order time-independent perturbation theory to a spin 1/2 particle. Energy corrections and eigenstates are derived using a perturbative Hamiltonian that includes a small perturbation in the spin direction Sy. The main goal of this paper is to present how a degenerate two-level system can be analysed systematically using principles of quantum mechanics and perturbation theory.