Professor Susskind presents the Hamiltonian for a quantum field, and demonstrates how these Hamiltonians describe particle interactions such as decay and scattering. He then introduces the field theory for fermions by deriving the Dirac equation. The theory behind the Dirac equations was the first theory to account fully for special relativity in the context of quantum mechanics. This relativistic Schrödinger equation implies the existence of antimatter. Topics: Hamiltonian Dirac equation Klein-Gordon equation Antimatter