All Questions
Tagged with quantum-chromodynamics non-perturbative
30
questions
8
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What's the difference between perturbative QCD, non-perturbative QCD, and gauge theory QCD?
I'm trying to get the ideal of QCD, and it turns out that there seems to be several versions, and some of which does not appear to agree with each other at a glance.
What's the difference, and how ...
- 3,256
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2
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QCD in the non-perturbative regime
In the list of unsolved problems in physics.
Confinement: the equations of QCD remain unsolved at energy scales relevant for describing atomic nuclei. How does QCD give rise to the physics of nuclei ...
- 441
8
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0
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Question about the vacua of the Standard Model
This question is probably based on a misunderstanding. Please correct me if I'm wrong, and if unclear, I'll try to put it in a clearer language.
In Yang-Mills theory such as the theory of strong ...
- 26.8k
7
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answer
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Why is the temporal gauge $A_0=0$ so popular in discussions of non-perturbative effects?
Almost every discussion of non-perturbative effects in Yang-Mills theory mentions in passing that they work in the temporal gauge. Why is this the case?
A good example is the QCD vacuum. Almost ...
- 10.1k
5
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3
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How is $\Lambda_{\textrm{QCD}}$ relevant in the non-perturbative regime?
The famous $\Lambda_{\textrm{QCD}}$ parameter enters through the one-loop running of the QCD coupling, through a relation similar to the following:
$$\alpha_S(Q^2)=\frac{\alpha_S(Q^2_0)}{1+b\ln(Q^2/Q^...
- 5,371
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2
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Are perturbative and non-perturbative QCD both signs of new physics?
I was studying about quarkonia systems and reached this page at CERN Courier. Here, I came across the following text:
While the failure to reproduce an experimental observable that is ...
- 4,954
5
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1
answer
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Continuum of lattice QCD is free?
I am having a hard time getting to grips with the statement that
$$g_{0}(a) \to 0 \text{ as } a \to 0$$
where $g_{0}$ is the bare coupling in lattice QCD and $a$ the lattice spacing.
How come this ...
- 609
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What constitutes a 'reliable' instanton calculation?
In Modern Supersymmetry, John Terning, on pgs 151, and 153 performs a so called 'reliable' instanton calculation when dealing with the ADS superpotential 'since the gauge group is completely broken'. ...
- 3,758
5
votes
1
answer
302
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Is CP problem the problem?
I've heard an argument that the question of smallness of QCD $\theta$ parameter is called the problem (namely, strong CP problem), since the other dimensionless couplings (like $\alpha_{s}$), are of ...
- 8,901
4
votes
1
answer
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How does AdS/CFT help us understand non-perturbative aspects of QCD?
I've heard AdS/CFT has found applications in many areas of physics where nonperturbative aspects leave us crippled in making any simple calculations.
Among these applications, I also have heard that ...
- 1,268
4
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2
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Reference request for non-perturbative QCD
I am looking for some good books or lecture notes that discuss non-perturbative aspects of QCD such as: chiral symmetry and chiral symmetry breaking; the QCD phase transition and the QCD phase diagram;...
4
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0
answers
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Perturbative coupling for QFT
I'm confused about the definition of a perturbative coupling for QFT that it should be less than 4 $\pi$, because the higher order corrections comes of order $\lambda/(4 \pi)$ ..
Now why QCD is not ...
- 453
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Some questions about QCD [closed]
About QCD, I have two questions. I know I should propose one question one time, but they are actually two steps of the same question: Non-perturbative aspects of QCD.
1, Why do we need to solve QCD ...
- 3,691
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Why is QCD hard to solve if I know the beta functions?
Why is it still hard to solve QCD if we know the beta functions of the coupling? Aren't only the loops causing problems? And am I not able to write every possible interaction exact at tree-level with ...
- 2,147
3
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1
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Why is lattice QCD called non-perturbative?
Like, if you are approximating a smooth structure with a discrete lattice, isn't this like a perturbation from smooth space-time?
If Feynman diagrams are a perturbative method, why are Feynamn ...
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