I've been reading about Bose-Einstein condensates, in which multiple bosons can occupy the same quantum state. I thought I understood how that could work until I learned that some atoms, such as Helium-4, are bosons.(adsbygoogle = window.adsbygoogle || []).push({});

It seemed to me that if two He-4 atoms H1 and H2 occupy the same quantum state then the four electrons must occupy the available electron quantum states, of which there are only two, so at least one of the electron quantum states must be occupied by more than one electron, which would violate the Pauli Exclusion Principle (as electrons are fermions).

Since this doesn't happen, there must be something wrong with my attempt at reasoning.

I would be grateful if someone can help me understand where I've gone wrong.

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# How can bosons made of fermions occupy the same quantum state?

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