TODO. Can't find it easily. Anyone?

This is closely linked to the <Pauli exclusion principle>.

What does a particle even mean, right? Especially in <quantum field theory>, where two electrons are just vibrations of a single electron field.

Another issue is that if we consider <magnetism>, things only make sense if we add <special relativity>, since <Maxwell's equations require special relativity>, so a non approximate solution for this will necessarily require full <quantum electrodynamics>.

As mentioned at <david tong s 2009 quantum field theory lectures at the perimeter institute/lecture 1> https://youtube.com/watch?video=H3AFzbrqH68&t=555[], <special relativity>[relativistic] quantum mechanical theories like the <Dirac equation> and <Klein-Gordon equation> make no sense for a "single particle": they must imply that particles can pop in out of existence.

Bibliography:
* https://www.youtube.com/watch?v=Og13-bSF9kA&list=PLDfPUNusx1Eo60qx3Od2KLUL4b7VDPo9F "Advanced quantum theory" by <Tobias J. Osborne> says that the course will essentially cover multi-particle quantum mechanics!
* https://physics.stackexchange.com/questions/54854/equivalence-between-qft-and-many-particle-qm "Equivalence between QFT and many-particle QM"
* Course: Quantum Many-Body Physics in Condensed Matter by Luis Gregorio Dias (2020) from <course: Quantum Many-Body Physics in Condensed Matter by Luis Gregorio Dias (2020)> give a good introduction to non-interacting particles


Solutions of the schrodinger equation for two electrons

ID: solutions-of-the-schrodinger-equation-for-two-electrons