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For a change in topic...

"The Pauli exclusion principle disallows two identical half-integer spin particles (electrons and all other fermions) from simultaneously occupying the same quantum state." Yet two neighboring hydrogen atoms can each have an electron in the 1s state. Is the physical separation sufficient to be identified as separate quantum states? If so, why isn't the same true inside white dwarfs where electron degeneracy is sufficient to prevent gravitational collapse?

To ask in a different form - why are two electrons allowed to simultaneously be in hydrogen 1s states in different atoms but are disallowed to be in the same quantum state in stellar material?

Thanks

lcwelch wrote:To ask in a different form - why are two electrons allowed to simultaneously be in hydrogen 1s states in different atoms but are disallowed to be in the same quantum state in stellar material?

Electrons in two neighboring hydrogen atoms are not in the same state. They obviously have two different positions.

minkwe wrote:

lcwelch wrote:To ask in a different form - why are two electrons allowed to simultaneously be in hydrogen 1s states in different atoms but are disallowed to be in the same quantum state in stellar material?

Electrons in two neighboring hydrogen atoms are not in the same state. They obviously have two different positions.

Fair enough - but why isn't the same thing true for two electrons on the opposite sides of a white dwarf?

lcwelch wrote:Fair enough - but why isn't the same thing true for two electrons on the opposite sides of a white dwarf?

Read last para of intro here: https://en.wikipedia.org/wiki/Energy_level
Then have a read here: http://hyperphysics.phy-astr.gsu.edu/hb ... hdwar.html
There is never 'state degeneracy' for Fermions, but energy degeneracy is certainly allowed in a system such as a white dwarf. This query is not really about a foundational issue and would imo be better shifted to the Cond-matter or Astro sub-forum.