Moderator's note: this is a spin off from a previous thread here. I confess to a very limited understanding of QM. I understand (somewhat) that a state of a particle can be a combination of possible states. I do not understand how a particle can be a combination of two particles. In particular, a particle has measurable properties such as: energy, momentum, position, and time of measurement. Of course there are uncertainty constraints on the precision of such measurements, and predictions about measurements are probabilistic. Can you explain the physics of how the energy, momentum, position, or time of measurement of a single particle can be a combination of such measurements of two particles.