Pauli Exclusion Principle

[RichIsnang]

From what i understand, the principle states that no two identical fermions can occupy the same quantum state at one time.

i have a few of queries:

Is there no two electrons in the same quantum state in the whole universe?

If two electrons are on either side of the universe, can they be in the same quantum state?

Would we not have noticed this? If we try and put an electron into a quantum state, but it some galaxy far far away (pardon the pun ) there is already an electron in that quantum state, would we have trouble putting it into that state? is it not possible?

or would it force the other electron out of that state? violating information/speed of light.

or is it possible to have two electrons in the same state if they are far away from each other?

if so what's the limit of distance? how far apart do they have to be?

why?

and how many different quantum states are there? an infinite number?

does it take a ton of energy to put electrons in some of the quantum states?

its alot of questions i know

i can split them up if needs be

 

rich

[mathematic]

In general electrons in different atoms would not have the same quantum state, more precisely, would not have the same wave function. The Pauli principle is usually used to describe the states of electrons in the same atom.

[swansont]

Electrons in separated systems are generally (though not universally) thought to have distinct wave functions, so they are in different states even if the energy, spin etc. are the same.

[RichIsnang]

does having the same wave function mean they have to same probability of being found in the same place?

[swansont]

does having the same wave function mean they have to same probability of being found in the same place?

 

It can if the wave function had a spatial dependence. That would be one of the differences between the states of electrons in different systems.

[ArjenDijksman]

If two electrons are on either side of the universe, can they be in the same quantum state?

 

The location of the electron is part of the description of a quantum state, so if two electrons do not have the same location they are not in the same quantum state. Whatsoever, they can of course be in the same quantum state with respect to the other quantum properties (energy, momentum, angular momentum and spin), but their complete wavefunction won't be the same.