Teaching MPPSC Assistant Professor Mock Test Series 2025 Chemical Sciences Approximate Methods of Quantum Mechanics Perturbation Theory
The ground state of a certain system with energy ϵ0 is subjected to a perturbation V, yielding a first-order correction ϵ1. If E0 is the true ground-state energy of the perturbed system, the inequality that always holds is
1
ϵ1 ≥ 0
2
ϵ0 ≥ E0
3
ϵ0 + ϵ1 ≤ E0
4
ϵ0 + ϵ1 ≥ E0