Quantum Field Theory

Quantum field theory is the classic example of a successful quantum field theory. Quantum mechanics cannot give an account of photons which constitute the prime case of relative 'particles'. At the speed c, a non-relativistic theory such as ordinary QM cannot give even an estimated description as photons have rest mass zero and similarly move in the vacuum. Photons play a vital role in the radiation and absorption processes which has to be executed; for instance, when one of an atom's electrons makes a transition between energy levels. The formalism of QFT is required for an explicit explanation of photons. When the theoretical framework of quantum mechanics was established, a small group of scientists tried to extend quantum methods to electromagnetic fields and contributed in modern developments of quantum field theory such as Algebraic quantum field theory, Axiomatic quantum field theory and Topological quantum field theory.