Question regarding the Pauli Exclusion Principle?

Click For Summary

Discussion Overview

The discussion revolves around the Pauli Exclusion Principle and its implications for protons as fermions within atomic nuclei, particularly in the context of elements with many protons, such as gold. Participants explore the nature of quantum states and how protons can coexist without violating the principle.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asserts that protons are fermions with +1/2 spin and questions how they can coexist in large numbers within a nucleus without violating the Pauli Exclusion Principle.
  • Another participant clarifies that while protons can have the same total spin, they must differ in other quantum numbers, such as spin direction and energy state, to comply with the principle.
  • A different viewpoint suggests that if nucleons were forced into the same space, they would occupy different energy states rather than 'disappearing', referencing electron degeneracy pressure as a related phenomenon in neutron stars.
  • One participant challenges the assertion that every proton in the universe occupies a different quantum state, questioning the feasibility of this claim.
  • A subsequent reply reiterates that protons in different positions are not in the same state, thus the Pauli Exclusion Principle does not apply in this context.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the Pauli Exclusion Principle for protons in atomic nuclei. While some agree on the necessity of differing quantum states, others question the universality of this assertion, indicating that the discussion remains unresolved.

Contextual Notes

There are unresolved assumptions regarding the nature of quantum states and the implications of the Pauli Exclusion Principle in large atomic systems. The discussion does not reach a consensus on the extent to which protons can be said to occupy unique quantum states across the universe.

zeromodz
Messages
244
Reaction score
0
Okay, I think everyone here knows what the principle states, so I am not even going over that. Is a proton not a fermion with is +1/2 spin? It has an half integral, hence it must be. However, how is this possible for a proton to be fermion when elements like gold have a lot of protons in the nucleus.

These protons are pushed together by the atomic force, why don't they disappear because they have asymmetrical wave functions, hence they should cancel out?
 
Physics news on Phys.org
The Pauli Exclusion Principle states that no two fermions can have the same quantum state. Quantum state meaning the assortment of quantum numbers that the wave function has in order to describe the system. Sure two protons can have the same total spin, but other things like their spin direction, i.e along the z-axis or the x-axis, or their principal quantum number ,which is their energy state, cannot be the same.

Anyway, yes protons and neutrons are spin 1/2 fermions that do obey the Pauli Exclusion Principle. Just with different quantum numbers other than total spin.

I hoped this helped
 
Easy. They're not in the same place or state.

If you were to push the nucleons together so they occupied the same space, then the Pauli principle would not lead to them 'disappearing'. (The fact that the wave function 'disappears' means it's an invalid wave function. It's not a solution to the S.E. It doesn't happen.) What happens if they're pushed into the same space is that they're then forced to occupy different (higher) energy states.

This manifests itself as http://en.wikipedia.org/wiki/Electron_degeneracy_pressure" . Which is what keeps neutron stars from collapsing in on themselves.
 
Last edited by a moderator:
Okay, I guess you guys answered it, but don't you think your pushing when you say out of all the atoms in the universe, every single proton has a different quantum state?
 
zeromodz said:
Okay, I guess you guys answered it, but don't you think your pushing when you say out of all the atoms in the universe, every single proton has a different quantum state?

No, because protons that occupy different positions are not in the same state so the EP does not apply; and the universe is a big place with plenty of space.
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K