Learn QCD & QED: What you need know

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In summary: Group theory, differential geometry, etc can be learned from looking at websites, but you need to be very careful. For example, the mathworld site is a reliable source but it is far from introductory. This site gives the complete mathematical formalism behind the concepts it likes to explain, but it does NOT provide you with an intuitive notion of what is going on. This is the most difficult part to learn. For example, when studying group theory for physics (QM and field theory) you will need to have a notion of what this mathematical formalism is trying to achieve in "physical terms". I mean, for example it is very important to understand how group theory works in physics.
  • #1
michealsmith
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wat do u need to learn to learn qcd and qed
 
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  • #2
Ok ok ok, here are the Feynman lectures, highly recommended from just about anybody:



Audio:

And QED, a really short paperback by Feynman:
 
  • #3
If you really want to learn QED and QCD you will need:

Classical Field Theory
Classical Electrodynamics
Relativity
Group Theory
Relativistic and Non-Relativistic Quantum Mechanics
Introductory Quantum Field Theory
(and all the physics to be able to do the above listed subjects)

The books that MK listed are good (actually great if you already know the material) and QED by Feynman will give you and intuitive notion of the subject, but if I gave you the QED lagrangian and asked you to work out a cross section for a scattering event, you will have no clue what to do.
Good luck with your studies.
Cheers,
Ryan
 
  • #4
michealsmith said:
wat do u need to learn to learn qcd and qed

Here's the whole list as advised by Nobel laureate Gerard 't Hooft.
Most of it applies if you want to go all the way to QCD.

HOW to BECOME a GOOD THEORETICAL PHYSICIST:

http://www.phys.uu.nl/~thooft/theorist.html


Regards, Hans
 
  • #5
Hans, that's an excellent site. Lots of good tutorials, thank you!
 
  • #6
Norman said:
If you really want to learn QED and QCD you will need:

Classical Field Theory
Classical Electrodynamics
Relativity
Group Theory
Relativistic and Non-Relativistic Quantum Mechanics
Introductory Quantum Field Theory

What is group theory?
I looked it up and at first it seemed like another way of manipulating numbers, like matrices or tensors, but then they got into 'classifications of geometry' and permutations and now I'm totally confused.
 
  • #7
tashi said:
What is group theory?
I looked it up and at first it seemed like another way of manipulating numbers, like matrices or tensors, but then they got into 'classifications of geometry' and permutations and now I'm totally confused.
The example of the rotation group may help you to understand it.
 
  • #9
good sites ..thanks
 
  • #10
At the risk of sounding like some old fashioned dude i would like to say that subjects like group theory, differential geometry, etc cannot be learned from looking at websites. For example, although the mathworld site is a reliable source it is far from introductory. This site gives the complete mathematical formalism behind the concepts it likes to explain, but it does NOT provide you with an intuitive notion of what is going on. This is the most difficult part to learn. For example when studying group theory for physics (QM and field theory) you will need to have a notion of what this mathematical formalism is trying to achieve in "physical terms". I mean, for example it is very important to understand how group theory works in physics.

"Basically you want an equation to be invariant under some transformations. In order to achieve that, the elementary building blocks of this system need to transform according to the socalled irreducible representations of the symmetry group at hand. Quantumnumbers are used to denote these irreducible representations". "For example, if you want the probability of a wavefunction to be invariant under rotations, the wavefunction itself will have to transform as an irreducible representation of the rotation group"

If you are able to translate this in mathematical terms and apply this onto some field equation, you will very soon realize that the use of group theory in field theory is always analoguous. Then you will also be able to comprehend why a phonon has spin 0, why there are only 8 gluons and why a baryon exists out of 3 quarks and a meson out of 2 quarks. Or how quantumnumbers are "born" and why you have only that many values for the magnetic quantum number

I suppose, what i want to say here is : GO TO COLLEGE and BUY THOSE BOOKS, AND START STUDYING. You should not ask such questions like "what do i need to study for ..." here in a public forum. Go consult your student advisor at college.


marlon
 
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Related to Learn QCD & QED: What you need know

1. What is QCD and QED?

QCD (Quantum Chromodynamics) and QED (Quantum Electrodynamics) are two of the fundamental theories of physics that describe the behavior of subatomic particles and their interactions with each other.

2. Why is it important to learn QCD and QED?

QCD and QED are essential for understanding the properties and behavior of matter at a fundamental level. They are also crucial for many modern technologies, such as particle accelerators and nuclear power plants.

3. What are the main differences between QCD and QED?

The main difference between QCD and QED is the types of particles and forces they describe. QCD deals with the strong nuclear force and the behavior of quarks and gluons, while QED deals with the electromagnetic force and the behavior of electrons and photons.

4. How does QCD and QED relate to the Standard Model of particle physics?

QCD and QED are both important components of the Standard Model, which is the current theory that explains the behavior of all known subatomic particles and their interactions. QCD and QED provide the framework for understanding the strong and electromagnetic forces, respectively, which are two of the four fundamental forces in the Standard Model.

5. Can QCD and QED be applied to other fields of science?

While QCD and QED are primarily used in particle physics, they also have applications in other fields such as cosmology, astrophysics, and condensed matter physics. They provide a powerful framework for understanding the behavior of matter at a microscopic level and can be applied to a wide range of phenomena.

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