B Is There Experimental Proof for the Existence of Fermion Fields?

[bluecap]

It is natural to make quantum fields out of electromagnetic wave or even the weak force. But is there experimental proof for the need to create fermion fields like separate electron fields for the electron.. quark fields for the quarks..

When de Broglie tried to propose matter wave from analogy with photons. It can be tested by experiments that the concept of matter wave is correct.. like single electron at a time double slit experiments.. but what about matter fields.. what experiment(s) prove it?

 

[Vanadium 50]

g-2 of the electron to 12 decimal places.

 

[haael]

Are you asking for justification for matter fields (i.e. that not only interactions are fields but matter too) or fermionic fields (i.e. that not all fields are bosonic but some are fermionic too)?

It is not more natural to postulate bosonic than fermionic fields. Both are equally weird. In fact, without fermionic fields, quantum theory is incomplete.

Justification for matter fields comes from requirement of quantization. Matter is quantized too, so it must be a quantum field.

 

[cosmik debris]

In a Quantum Field Theory fields are the fundamental entity. All species of particles are different and require their own field to represent them but all particles of a specie are identical and can be represented as an excitation of the particle field. This model is known to work pretty well as Mr Vanadium has pointed out by being experimentally verified to 12 decimal places.

 

[stevendaryl]

You can sort of intuitively understand matter fields as simply a way of doing many-particle quantum mechanics where the particles are indistinguishable and are subject to the Fermi or Bose statistics--that is, the wave function must be symmetric (bosons) or anti-symmetric (fermions) under particle exchange. If you are doing non-relativistic physics, where the number of fermions can be assumed to be constant, then the equivalence between doing many-particle quantum mechanics and doing field theory, with fermion fields, is exact. Relativistically, introducing matter fields makes a difference, because that allows you to describe processes where the number of particles can change.

But I don't think that there is a big conceptual leap between many-particle quantum mechanics and quantum field theory with matter fields.

 

[Feeble Wonk]

--that is, the wave function must be symmetric (bosons) or anti-symmetric (fermions) under particle exchange.

It will be difficult to do without going over my head, but could you please elaborate on this idea.

 

[stevendaryl]

It will be difficult to do without going over my head, but could you please elaborate on this idea.

My original answer was perhaps way beyond the "beginner" level of this thread, as Vanadium 50 reminded me. I will try to come up with a more appropriate answer.

 

[Mentz114]

It will be difficult to do without going over my head, but could you please elaborate on this idea.

I see it like this - if we have a collection of bosons then swapping two of them that have the same energy makes no difference to the (symmetric) wave function.

But doing the same with 2 fermions which have the same energy/spin would send the wave fuction to zero. Apparently this means we cannot ever find two such fermions.

It works for me.

 

[bluecap]

I'd better answer this here so it won't be off topic in the thread "Shape of Elementary Particles in QFT, etc". I wrote:
"so what kind of instruments can theoretically image Bohmian electron fields for example? For bohmians particles. We can see them with our own eyes."
Demystifier answered: "When you see a macroscopic object, e.g. a chair, do you see the particles or the field?"

I see particles. But just for sake of discussion. How would it look like if let say my brain had evolved mechanism to image Bohmian quantum fields? (again just for sake of discussions for Mentors with itchy fingers on the lock thread button). Would the fields look like the object? Please give any drawing or references of the theoretical fields appearance of say the chair... won't it look like or be recognizable as a chair? Just an idea.