So two identical fermions can't occupy the same quantum state. But if one is same except higher in energy then the quantum wave pattern is different so can occupy the same space. Are there any values on the amount of energy needed to make two neutrons exist in the same space? I'm doing a research project into black holes and was wondering whether there was a possibility that the high density was due to the high energy allowing neutrons to overlap. If anyone also knew any other energy levels to do with black holes, neutron stars or collapsing stars??