Quantum it describes a fundamental aspect of energy not just restricted to photons. In the attempt to bring theory into agreement with experiment, Max Planck postulated that electromagnetic energy is absorbed or emitted in discrete packets, or quanta. Quantum In physics, a quantum (plural: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a physical property may be "quantized" is referred to as "the hypothesis of quantization". This means that the magnitude of the physical property can take on only discrete values consisting of integer multiples of one quantum. For example,
Interaction point Interaction point In particle physics, an interaction point (IP) is the place where particles collide in an accelerator experiment. The "nominal" interaction point is the design position, which may differ from the "real" or "physics" interaction point, where the particles actually collide. A related, but distinct, concept is the "primary vertex": the reconstructed location of an individual particle collision. For fixed target experiments, the interaction point is the point where beam and target interact. For colliders, it is the place where the beams interact. Experiments (detectors) at particle accelerators are built around the nominal interaction points of the accelerators. The