If you have two hydrogen atoms as your system, then you use the many body schrodinger equation for 2 protons and 2 electrons. The coulombic repulsion between the two atoms is built into the SWE, so is there a range of different possible magnitudes for the repulsion? If so, does the system decide at which magnitude to repel based on quantum randomness? Lastly, how would that translate to the macroscopic world. Is the range of different possibilities just too small to ever notice? The reason i ask this is because when i, say, push on a chair, my finger atoms and the chair atoms are definitely repelling, so is that system just randomly choosing the magnitude of repulsion?