How to calculate Feynman diagrams in phi^4

In summary, the conversation is about calculating diagrams for quartic scalar field theory. The question is asking for an intuition on how to calculate the diagrams, and the person suggests using the Feynman rules and references some resources for further help. The conversation also mentions the difficulty of self-studying in this topic.
  • #1
Higgsy
21
0
For quartic scalar field theory these are some of the lowest order diagrams (taken from the solutions to 9.2 srednicki). I'm wondering if someone can give me an intuition of how to actually calculate them.

What I'm thinking is that vertices are $$\int \frac{d^{4}x}{(2\pi)^{4}}$$ and for the first diagram their would be two contractions $$\Delta (0)$$ because the propagators return to the place they originated at. So would the first diagram just be $$\Delta (0) ^{2} \int \frac{d^{4}x}{(2\pi)^{4}}$$

Self-studying is incredibly difficult! Any help would be much appreciated! :)
 

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  • #2
Try finding your answer in this website:
http://bolvan.ph.utexas.edu/~vadim/classes/2004f.homeworks/HWpage.html

If it doesn't appear there then try searching for solutions to Peskin and Schroeder, try reading the book.

There's also the book called diagrammatica by Veltman if I am not wrong that should have a good description on how to calculate it for quartic term.
 

1. How do I determine the number of loops in a phi^4 Feynman diagram?

The number of loops in a phi^4 Feynman diagram is equal to the number of internal lines (propagators) minus the number of external lines.

2. What is the significance of the coupling constant in calculating Feynman diagrams in phi^4 theory?

The coupling constant in phi^4 theory represents the strength of the interaction between the particles and plays a crucial role in determining the overall probability amplitude of the Feynman diagram.

3. How do I handle divergences in my phi^4 Feynman diagram calculations?

Divergences in phi^4 Feynman diagrams can be handled by using renormalization techniques, which involve adjusting the parameters of the theory to account for these infinities.

4. Can I simplify my phi^4 Feynman diagram calculations?

Yes, there are several techniques such as Feynman parametrization and dimensional regularization that can be used to simplify phi^4 Feynman diagram calculations.

5. What is the physical interpretation of the phi^4 Feynman diagrams?

The phi^4 Feynman diagrams represent the possible paths of particles interacting through the phi^4 interaction. The amplitude of each diagram corresponds to the probability of that particular interaction occurring in the physical system.

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