The electric field in an excited hydrogen atom is non-zero over a bigger volume than the electric field in a ground-state hydrogen atom. The energy associated with this extra electric field must be provided to excite the ground-state atom.
Intuitively, it is clear that in a system where the potential energy of the electron is lower, the overall mass is also lower. There's less energy here.
When two nucleons bind together. Their masses decrease. Is there a similar analog change in wave function between them akin to a reduction in the volume of the electric field of the electron? Is it possible to conceptualize this loss of mass through the change of component wave functions/behavior?
Does the exchange of pions/residual strong force alter the probability densities in a way where it is clear that the wave function of the bound systems possess less energy than unbound?
I would like to know if it's possible to explain mass defect without using the phrase "binding energy" or "Minus the energy it takes to separate the components"