Antimatter and quantum mechanics This question could have a very simple answer but I could not find that answer anywhere. My question is since electrons, protons, etc they all have their antiparticles, why are not they mentioned in Quantum Physics? And if they are real, should not they be included into Schrödinger equation?
 A: The non-relativistic behavior of antiparticles can be understood with the Schrodinger equation. For example, anti-hydrogen is approximated by the Schrodinger equation to the same accuracy as hydrogen is. This is often never mentioned in an introductory Quantum Mechanics course.
But the relationship between particles and antiparticles can only be understood using relativistic quantum mechanics, such as the Dirac equation or relativistic quantum field theory. Quantum electrodynamics (QED) is an example of the latter and explains, among many other things, how an electron and a positron can annihilate into photons.
Since charged particles and their antiparticles can annihilate to produce photons, which are never non-relativistic, the non-relativistic Schrodinger equation cannot explain this interaction. Also, the Schrodinger equation cannot represent particles or antiparticles appearing or disappearing, like QED can. But the Schrodinger equation can explain how an anti-proton binds with an anti-electron (positron) to make anti-hydrogen, since this does not involve relativistic processes and no particles appear or disappear.
