Potential Problems in Quantum Electrodynamics

Two possible paths of an electron being scattered between the states Ψ₁ and Ψ₂ were discussed in the last lecture. These are:

Case I. Both Ψ₁, Ψ₂ states of positive energy, interpreted as Ψ₁ electron in “past,” Ψ₂ electron in “future.” This is electron scattering.

Case II. Both Ψ₁, Ψ₂ states of negative energy interpreted as Ψ₁ positron in “future,” Ψ₂ positron in “past.” This is positron scattering.