Individual #quantum_field_theory__quantumfieldtheory  the branch of quantum physics that is concerned with the theory of fields; it was motivated by the question of how an atom radiates light as its electrons jump from excited states
  >part of:  quantum_physics  the branch of physics based on quantum theory
  >part:  quantum_electrodynamics__quantumelectrodynamic__QED  a relativistic quantum theory of the electromagnetic interactions of photons and electrons and muons
  >part:  quantum_chromodynamics__QCD  a theory of strong interactions between elementary particles (including the interaction that binds protons and neutrons in the nucleus); it assumes that strongly interacting particles (hadrons) are made of quarks and that gluons bind the quarks together

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