- Quantum mechanics is a fundamental theory in physics that provides a lens on the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including, particle physics, quantum field theory and quantum electrodynamics which are introduced below.
- Particle physics is an experimental subfield of quantum mechanics often associated with the Large Hadron collider at CERN that studies the fundamental particles that make up matter and the forces that act between them. Among the most important discoveries of particle physics was the discovery of the photon and the dual nature of light (both a wave and particle).
- Quantum field theory (QFT) is a theoretical framework that describes particles as excitations of underlying quantum fields. The Standard Model is a QFT theory that describes the three fundamental forces of nature (the electromagnetic force, the weak nuclear force, and the strong nuclear force).
- Quantum electrodynamics (QED) is a quantum field theory that describes the interaction of light with charged particles. It describes how electromagnetic interactions work at the quantum level. QED has accounted for properties of light such as the photoelectric effect and Compton scattering.