Why do we know the particle/quantum field theory is phys of symmetries

In summary: Symmetry is a fundamental principle of QFT which allows us to describe the world in a way that is consistent with observation and experiment.
  • #1
ndung200790
519
0
Why do we know that particle physics/quantum field theory is a physics of symmetries?What leads we to the gauge symmetries of all interactions?.Why we can not assume a physics without symmetry?
 
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  • #2
Of course you can do it without symmetries. Its just most beautiful and elegant that way.

Thanks
Bill
 
  • #3
ndung200790 said:
Why do we know that particle physics/quantum field theory is a physics of symmetries?
This comes from Noether's theorem.
 
  • #4
ndung200790 said:
Why do we know that particle physics/quantum field theory is a physics of symmetries?What leads we to the gauge symmetries of all interactions?.Why we can not assume a physics without symmetry?

I'm a bit puzzled by this question.

Since you're asking specifically in reference to "particle physics/quantum field theory", does that mean that you have no issues with the concept of symmetries being used in classical physics and other areas? If so, then this makes no sense, since the SAME principle and idea are at work here. DaleSpam has eluded to such a principle.

So what is it about "particle physics/quantum field theory" that made you ask such a question, but not for classical physics?

Zz.
 
  • #5
ndung200790 said:
Why do we know that particle physics/quantum field theory is a physics of symmetries?What leads we to the gauge symmetries of all interactions?.Why we can not assume a physics without symmetry?

A symmetry implies the existence of a conserved quantity, and we know by observation and experiment that the world (both quantum and classical, as ZZ points out) is full of conserved quantities. That's a pretty good hint that investigating symmetries will be a fruitful way of investigating the world, and so far experience has supported that approach.

That doesn't necessarily make it the only approach, but as long as it works and no one has found a better approach, it's going to be the one that's most widely used.
 
  • #6
ndung200790 said:
Why do we know that particle physics/quantum field theory is a physics of symmetries?What leads we to the gauge symmetries of all interactions?.Why we can not assume a physics without symmetry?

If you were starting out to make a theory you would like it to work no matter where you choose to set the origin in space (x=0), whenever you choose the zero of time to be (t=0) whatever you set the zero of velocity of the frame of reference to be, wherever you set the direction of angle of zero to be and wherever you chose to set the zero of the EM field etc. This is necessary if you think about it as we make these choices of where the zeros are and they are arbitrary. These are the symmetries of the theories.

By making the model describing the physics invariant under all these choices leads naturally to the conservation of certain quantities. For example
Invariance under time translation leads to conservation of energy
Invariance under rotation leads to conversation of angular momentum
EM gauge invariance leads to conservation of charge
Etc.

Which is in line with what we find in experiments. It's pretty amazing!
 
  • #7
bhobba said:
Of course you can do it without symmetries. Its just most beautiful and elegant that way.

Thanks
Bill

No, we can not do QFT without symmetries.
 
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FAQ: Why do we know the particle/quantum field theory is phys of symmetries

1. Why is symmetry important in particle/quantum field theory?

Symmetry is important in particle/quantum field theory because it helps us understand and describe the fundamental laws and interactions of the universe. Symmetry principles, such as gauge symmetry and Lorentz symmetry, are essential for the consistency and predictive power of our theories. They allow us to make precise predictions about the behavior of particles and their interactions, which can then be tested through experiments.

2. What is the connection between symmetry and conservation laws in particle/quantum field theory?

In particle/quantum field theory, symmetry and conservation laws are closely linked. Noether's theorem states that for every continuous symmetry in a physical system, there is a corresponding conservation law. For example, the conservation of momentum is a result of translational symmetry, and the conservation of energy is a result of time translation symmetry. This connection allows us to predict and understand the behavior of particles through the study of symmetries in their underlying theories.

3. How does the concept of symmetry help us unify different forces in particle/quantum field theory?

The concept of symmetry is crucial in the search for a unified theory of all the fundamental forces in the universe. By finding symmetries that are shared among different forces, we can develop theories that can explain and unify these seemingly distinct interactions. For example, the electroweak theory successfully unifies the electromagnetic and weak forces by incorporating a symmetry known as the SU(2) gauge symmetry.

4. Can symmetries be broken in particle/quantum field theory?

Yes, symmetries can be broken in particle/quantum field theory. This phenomenon, known as symmetry breaking, occurs when the symmetries of a system are not present in its lowest energy state. This leads to the emergence of new properties or particles that were not apparent in the original symmetrical theory. The breaking of symmetries is an essential aspect of many theories, such as the Standard Model, where the Higgs field breaking of the electroweak symmetry explains the masses of particles.

5. How do experiments confirm the role of symmetries in particle/quantum field theory?

Experiments play a crucial role in confirming the role of symmetries in particle/quantum field theory. Through high-energy particle colliders, scientists can test the predictions of symmetrical theories and observe the behavior of particles and their interactions. The discovery of the Higgs boson, which confirmed the breaking of the electroweak symmetry, is an example of how experiments have validated the role of symmetries in our understanding of the universe.

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