I present an alternative and rather direct way to derive the well known Schr\"odinger equation for a quantum wavefunction, by starting with the Klein Gordon equation and applying a directional factorization scheme. And since if you have a directionally factorizing hammer, everything looks like a factorizable nail, I also derive an alternative wavefunction propagation equation in the momentum-dominated limit. This new Schr\"odinger $p$-equation therefore provides a potentially useful complement to the traditional Schr\"odinger $m$-equation's mass-dominated limit.
Categories: quant-ph