Strange quarks are found in subatomic particles called hadrons. Charm quarks are found in hadrons, which are subatomic particles made of quarks. Particle phenomenology systematizes the knowledge about subatomic particles obtained from these experiments. The tau lepton is predicted to form exotic atoms like other charged subatomic particles. Quantum mechanics is the theory of atoms and subatomic systems. Particle radiation is the radiation of energy by means of fast-moving subatomic particles. The study of subatomic particles "per se" is called particle physics. Synchrotrons were originally designed for use by high-energy physicists studying subatomic particles and cosmic phenomena. Entanglement is usually created by direct interactions between subatomic particles. This same illusion manifests itself in the observation of subatomic particles. When subatomic particles interact, different outcomes are possible. Phosphorescent materials can also be excited by bombarding them with subatomic particles. The charges of ions and subatomic particles are also denoted by superscripts. Electric charge is a characteristic property of many subatomic particles. They are conventionally parameterized with "flavour quantum numbers" that are assigned to all subatomic particles.