What Force Causes Electron Repulsion in the 1s State?

In summary: Both the exclusion principle and the HUP are fundamental principles in quantum mechanics. The exclusion principle, also known as the Pauli exclusion principle, states that no two identical fermions can occupy the same quantum state simultaneously. This is due to the spin-1/2 nature of electrons and does not involve any external force. The HUP, or Heisenberg's uncertainty principle, states that there is a fundamental limit to the precision with which certain physical quantities can be measured. It is derived from the axioms of quantum mechanics and does not involve any force or connection to the exclusion principle. Both principles play crucial roles in understanding the behavior of particles at the quantum level.
  • #1
pivoxa15
2,255
1
There must be a force repulsing the electrons for no more than two in the 1s state for example. What force is that?

How is this principle connected to the HUP?
 
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  • #2
There is no force behind the exclusion principle -- until you get to phenomenological models in condense matter theory, which occasionally postulates such a fictitious force. The exclusion principle is solely due to the spin-1/2 nature of electrons.
 
  • #3
And there's no connection with the HUP, since this follows from the axioms without considering the symmetrization/antisymmetrization of the state vector.
 
  • #4
As the others said, there is no force behind the Pauli principle. In fact, the pauli prinicple can be the SOURCE of force, degenerate pressure; in for example White dwarf stars, and neutron stars.
 
  • #5
I find that hard to believe. How then can particles know about the presence of the other?

There must be messenger particles of somesort?
 
  • #6
dextercioby said:
And there's no connection with the HUP, since this follows from the axioms without considering the symmetrization/antisymmetrization of the state vector.

So the HUP is more fundalmental?

Is Pauli's exclusion principles derived experimentally or theoretically?
 
  • #7
pivoxa15 said:
I find that hard to believe. How then can particles know about the presence of the other?

There must be messenger particles of somesort?

Welcome to the world of Quantum mechanics! =)
 
  • #8
pivoxa15 said:
So the HUP is more fundalmental?

Is Pauli's exclusion principles derived experimentally or theoretically?

According to what I have learned (and my books do not mention anything else), it is derived theoretically. Just look it up in your QM books in the chapters on "Identical particles".



And what do you mean "more fundamental", the HUP is also derived from theory, not so very difficult either.
 
  • #9
Pivoxa, it may help you to visualize the PEP this way. Imagine that a fermion is a condensation of the quantum vacuum field, and that the field has a "carrying capacity". In other words, the field cannot support the existence of two identical fermions in the same state. The fermions do not "know" where they are in relation to one another, nor do they repel one another - their failure to superimpose is a characteristic limitation of the field in which they arise. The existence of a fermion in a quantum state drives the probability of the existence of a same-spin twin in that same quantum state toward zero.
 
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  • #10
All physics is experimental -- otherwise it's maths. The uncertainty principle is was a *principle* when Heisenberg proposed it, extrapolating on experimental evidence; now, we tend to derived it, as a consequence of the formalism (Hilbert spaces and projection operators). What is theoretical in one view is experimental in another. If you're serious about wanting to learn about quantum mechanics, get a good book -- I recommend Heisenberg's original, Physical Principles of Quantum Theory, which is a short and cheap book.
 
  • #11
pivoxa15 said:
So the HUP is more fundalmental?

Is Pauli's exclusion principles derived experimentally or theoretically?

No, the HUP is a consequence of the axioms, the Pauli exclusion principle is a conseqance of the axioms as well. Therefore none is more fundamental than the other.
 

FAQ: What Force Causes Electron Repulsion in the 1s State?

What is Pauli's exclusion principle?

Pauli's exclusion principle is a fundamental principle in quantum mechanics that states that no two identical fermions can occupy the same quantum state simultaneously. This means that in a given system, such as an atom, no two electrons can exist in the same energy level with the same spin.

Who discovered Pauli's exclusion principle?

Pauli's exclusion principle was discovered by Austrian physicist Wolfgang Pauli in 1925. It was a crucial development in understanding the behavior of electrons in atoms and led to the development of the quantum mechanical model of the atom.

What is the significance of Pauli's exclusion principle?

Pauli's exclusion principle is significant because it explains the structure of atoms and the behavior of electrons. It is also a fundamental principle in understanding the properties of matter, such as the stability of atoms and the periodic table.

How does Pauli's exclusion principle relate to the electron configurations of atoms?

Pauli's exclusion principle dictates that each electron in an atom must have a unique set of quantum numbers, including its energy level and spin. This means that the electron configurations of atoms follow specific rules, such as the Aufbau principle and Hund's rule, to ensure that all electrons follow the exclusion principle.

Are there any exceptions to Pauli's exclusion principle?

While Pauli's exclusion principle holds true for most cases, there are some exceptions, such as in the case of degenerate subshells or the presence of magnetic fields. In these cases, electrons may have the same energy level and spin, but will differ in other quantum numbers, allowing them to occupy the same quantum state.

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