Pauli's exclusion principle

In summary, the Pauli Exclusion Principle states that no two fermions can have the same quantum state, which loosely translates to no two identical fermions occupying the same position. This does not apply to particles like quarks and electrons merging, as they are not identical particles. Additionally, the exclusion principle only applies to fermions, not bosons, which can occupy the same position. In a universe without charge, different laws would apply and it may be possible to walk through solid walls.
  • #1
riz
So my question is why can't 2 object be at the exact same potion, (i.e. overlap). Why can't a +ve quark and electron just merge. In an universe where there is no force caused due to charge, why can't we just walk through a solid wall.
 
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  • #2
riz said:
So my question is why can't 2 object be at the exact same potion, (i.e. overlap). Why can't a +ve quark and electron just merge.
The Pauli Exclusion Principle says that no two fermions (a type of particle) can have the same quantum state. You can think of that very (very!) loosely as saying that no two identical fermions can occupy the same position.

Since a quark and an electron are not identical particles, the exclusion principle has nothing to say (so far as I know) about their ability to merge.

Also, the exclusion principle only applies to fermions. There are other particles called bosons, that can occupy the same position. You might be interested to read about Bose-Einstein condensates, that are an instance of this sort of thing.
In an universe where there is no force caused due to charge, why can't we just walk through a solid wall.
A universe without charge would be different from this one, and operate under different laws. So this question is about science fiction. I imagine one could make up a set of laws for a universe in which it is possible to walk through a wall.
 
  • #3
andrewkirk said:
The Pauli Exclusion Principle says that no two fermions (a type of particle) can have the same quantum state. You can think of that very (very!) loosely as saying that no two identical fermions can occupy the same position.

Since a quark and an electron are not identical particles, the exclusion principle has nothing to say (so far as I know) about their ability to merge.

isn't the ability "to merge" the very different behavior of bosons? Why do you say "loosely as saying that no two identical fermions can occupy the same position." I thought that was the whole other side of physics we can see the effects of. Bosons can, and Fermions can't isn't "loose".

You seem to suggest non-composite fermions can be in the same place at the same time; if they are say, a quark and a lepton...??

I just found out about this super odd physics through reading about helium 4 condensate, next to first hearing about the time travel implication of c, this is the coolest and most bizarre thing about physics.
 
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  • #4
Pauli exclusion principle says 'no two fermions can be in the same quantum state'. Quantum state is not the same as position.
Take helium atom, for instance. It has two electrons in the 1s state. That is, their spatial wave functions are identical and truly, they are in the same space at the same time but not in the same quantum state: their spins are different.
Pauli exclusion principle applies to the fermions of the same species, regardless if they are non-composite or not.
Take again helium as an example. It has two isotopes: Helium 3 and Helium 4. Helium 4 has 2 neutrons, 2 protons and 2 electrons - an even number of 1/2 spin particle, so the total spin has to be a multiple of 1 - hence it is a boson and does condense into a superfluid.
Helium 3 had only 1 neutron, hence an odd number of 1/2 spin particle and it is a fermion. It does not become superfluid.
 

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 two fermions, such as electrons, cannot have the same set of quantum numbers (i.e. energy, spin, and orbital angular momentum) in an atom.

How does Pauli's exclusion principle affect electron configurations in atoms?

The exclusion principle plays a crucial role in determining the electron configurations of atoms. It dictates that electrons must fill up the lowest energy orbitals first, and then move to higher energy orbitals. This results in the "building up" of the periodic table, with each element having a unique and distinct electron configuration.

Why is Pauli's exclusion principle important in understanding the properties of matter?

The exclusion principle is important because it explains the stability and behavior of atoms and matter. Without this principle, electrons would not be confined to specific energy levels and would collapse into the nucleus, making stable matter impossible. It also explains why atoms have a limited number of electrons in each energy level, and why elements have distinct chemical and physical properties.

Are there any exceptions to Pauli's exclusion principle?

While the exclusion principle holds true for most cases, there are a few exceptions. For example, in certain high-energy situations, such as in nuclear reactions, the principle may be temporarily violated. Additionally, in some special cases, such as with quarks, particles with the same quantum numbers can exist in the same state due to their strong interactions.

How did Pauli's exclusion principle come about?

The exclusion principle was first proposed by Austrian physicist Wolfgang Pauli in 1925. He formulated it to explain the structure of atoms and the periodic table, which had been observed but not yet understood at the time. Pauli's exclusion principle has since become one of the foundational principles of quantum mechanics and has been confirmed through numerous experiments and observations.

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