Thread:User talk:WaitingforGodot/Brian Cox/reply (10)

Well, bosons can occupy the same quantum state. That's how lasers can build up their intensity. And also how deuterium behaves very differently to hydrogen (protium) - as do the main isotopes of helium, where only one exhibits superfluidity.

That's not really the same as "same space", though. Different atomic orbitals overlap significantly in space, but won't necessarily have the same state or energy.