摘要: The dynamical quantum-mechanical wave equations of spin-0 pions, spin-1 vector particles, and massless photons are formulated in a consistent one-particle fashion. For the Klein-Gordon equation, interpretation negative-energy states as describing antiparticles is stressed. relativistic bound-state Coulomb problem then solved for π-mesic atoms. parallel made between massive photon equations. notion currents, current conservation gauge invariance amplitudes discussed detail linked to principle minimal replacement. Minimal coupling charged particles will be basis general electromagnetic interaction considered later chapters. Second-quantized field theories briefly described, an analogy (relativistic) nonrelativistic phonons.