- Wave function: a mathematical description of everything we know about a Quantum system, labelled with psi. Closely linked to the systems probability distribution
- Quantum system: something being studied using QM ie a particular electron moving, or a bunch of particles
- The true fundamental element of matter, particles are points in a quantum field
- Particle accelerators initiate disturbances in quantum fields
- Not absolute, they might appear for one observer in a particular frame of reference based on their speed