# Electrons and the Pauli exclusion principle

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• Philipsmett

#### Philipsmett

electrons are repelled using the Pauli exclusion principle?

electrons are repelled using the Pauli exclusion principle?

This is too vague to answer. What specific scenario are you thinking of?

This is too vague to answer. What specific scenario are you thinking of?
Touching is electromagnetic repulsion between electrons or the Pauli exclusion principle? How do physicists distinguish between these effects?

When two atoms come into contact

They don't. Atoms aren't little billiard balls; they don't have hard boundaries.

What you are asking about, I take it, is why, for example, a solid object like a rock is stable in a state in which the average spacing between atomic nuclei is something like ##10^{-10}## meters, instead of something much smaller. The classic paper on this topic is Dyson & Lenard:

https://aip.scitation.org/doi/10.1063/1.1705209

is this electromagnetic repulsion between electrons or the Pauli exclusion principle?

The short answer is "yes". The longer answer, as you will see if you read the paper I linked to above, is "it's complicated". But the proof of the theorem given in the paper takes into account both electrostatic interactions and the Pauli exclusion principle, so there isn't really a valid sense in which either one alone is dominant; they both play a significant role.

Another good paper on this topic is Lieb 1976:

http://www.pas.rochester.edu/~rajeev/phy246/lieb.pdf

the proof of the theorem given in the paper takes into account both electrostatic interactions and the Pauli exclusion principle

It's also worth noting that "electrostatic interactions" is more than just repulsion between electrons, and "Pauli exclusion principle" is more than just electrons from neighboring atoms not occupying the same state. In each individual atom, the electrons cannot all occupy the same state; that's why we have the periodic table of the elements. And there are also attractive Coulomb forces between the atomic nuclei and the electrons (not just within the same atom), and repulsive Coulomb forces between the different atomic nuclei (which are largely screened by the electrons, and that also has to be taken into account).

Another good paper on this topic is Lieb 1976:

http://www.pas.rochester.edu/~rajeev/phy246/lieb.pdf
It's also worth noting that "electrostatic interactions" is more than just repulsion between electrons, and "Pauli exclusion principle" is more than just electrons from neighboring atoms not occupying the same state. In each individual atom, the electrons cannot all occupy the same state; that's why we have the periodic table of the elements. And there are also attractive Coulomb forces between the atomic nuclei and the electrons (not just within the same atom), and repulsive Coulomb forces between the different atomic nuclei (which are largely screened by the electrons, and that also has to be taken into account).
Thanks for the information. According to the exclusion principle, the two electrons must interact directly, without the fundamental forces?

According to the exclusion principle, the two electrons must interact directly, without the fundamental forces?

No, the exclusion principle is not an "interaction". It's a constraint on the quantum state of any system consisting of multiple identical fermions. Its effects can appear to work similarly to "interactions", but that doesn't mean it's an interaction.

No, the exclusion principle is not an "interaction". It's a constraint on the quantum state of any system consisting of multiple identical fermions. Its effects can appear to work similarly to "interactions", but that doesn't mean it's an interaction.
But how do you know that electron shells are repelled by electrostatic interaction? Maybe this is the principle of exclusion? Is there an experimental fact?

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So you don't believe in Coulomb's Law? Or rather, you believe it for the opposite sign attraction between electron and nucleus, but not the same sign repulsion between electrons?

So you don't believe in Coulomb's Law? Or rather, you believe it for the opposite sign attraction between electron and nucleus, but not the same sign repulsion between electrons?
Well, just the carrier of these forces is not experimentally detected.

Well, just the carrier of these forces is not experimentally detected.

Of course the carrier of the EM force, the photon, has been experimentally detected.

Of course the carrier of the EM force, the photon, has been experimentally detected.
I am talking about excitation in an electromagnetic field that generates electrons when they repel each other.

Electrons are not created or generated when they repel each other.

Just about the least efficient or effective way to learn is by posting a series of incorrect statements, hoping that they will be corrected.

I am talking about excitation in an electromagnetic field that generates electrons when they repel each other.

This statement makes no sense. You are putting different things into a single sentence without any rhyme or reason.

First of all, do you even know and understand what is "excitation in the electromagnetic field"? And it also doesn't appear that you understand what exclusion principle is.

Applying two things that you don't understand to produce a third is a dubious way to do this discussion in this particular forum. You are threading on thin ice.

Zz.

I am talking about excitation in an electromagnetic field that generates electrons when they repel each other.
I apologize for the wrong statement.
I meant that, according to QFT, the electrons repulsed each other with virtual photons or generated excitation in an electromagnetic field that repelled them, but these excitations or virtual photons were not detected experimentally and therefore it is some kind of invisible force.

I apologize for the wrong statement.
I meant that, according to QFT, the electrons repulsed each other with virtual photons or generated excitation in an electromagnetic field that repelled them, but these excitations or virtual photons were not detected experimentally and therefore it is some kind of invisible force.

Where did you get the idea that these are not "detected experimentally"? Have you even done a search of the literature?

Notice how we are trying to go one step forward but ended up going two steps back?

Zz.

Where did you get the idea that these are not "detected experimentally"? Have you even done a search of the literature?

Notice how we are trying to go one step forward but ended up going two steps back?

Zz.

Defined "not found experimentally". Do you think the Higgs was found "experimentally"? What do you think they actually detected? Do you think the Pauli Exclusion Principle was confirmed "experimentally"?

Zz.

@Philipsmett, I think you would do well to cease lecturing and start listening.

Defined "not found experimentally". Do you think the Higgs was found "experimentally"? What do you think they actually detected? Do you think the Pauli Exclusion Principle was confirmed "experimentally"?

Zz.
Is it possible to say that there is electromagnetic force between electrons, and it is observed, but it is not known how this happens?

Is it possible to say that there is electromagnetic force between electrons, and it is observed, but it is not known how this happens?

It is not known how it happens to you, not to us.

Zz.

according to QFT, the electrons repulsed each other with virtual photons or generated excitation in an electromagnetic field

No, that's not what QFT says. You need to read this Insights article:

https://www.physicsforums.com/insights/misconceptions-virtual-particles/