Question About Calculation in Maggiore's Quantum Field Theory

Click For Summary
SUMMARY

The discussion centers on a calculation from Maggiore's "Modern Introduction to Quantum Field Theory," specifically regarding the equation on page 52: \(\delta x^\mu = w^\mu_\nu x^\mu = \sum_{\rho < \sigma} A^\mu_{(\rho \sigma)} w^{\rho \sigma}\). The participant encounters a factor of 3 in their results, questioning whether this is an error in the text. It is clarified that the author is correct, as the expression 'Aw' is typically represented as '1/2 Aw' due to the antisymmetry of A and w. Additionally, there is a suggestion that the definition of A should involve the metric 'g' for proper representation in the SO(4) vectorial framework.

PREREQUISITES
  • Understanding of Quantum Field Theory concepts
  • Familiarity with antisymmetric tensors
  • Knowledge of the SO(4) group and its representations
  • Basic proficiency in tensor calculus
NEXT STEPS
  • Study the properties of antisymmetric tensors in Quantum Field Theory
  • Learn about the role of the metric tensor 'g' in field theory calculations
  • Explore the SO(4) group and its applications in physics
  • Review the derivation of equations in Maggiore's "Modern Introduction to Quantum Field Theory"
USEFUL FOR

Students and researchers in theoretical physics, particularly those focusing on Quantum Field Theory and tensor analysis, will benefit from this discussion.

PJK
Messages
14
Reaction score
0
I have a question about an equation in Maggiore's Modern Introd. to Quantum Field Theory p.52:
[tex]\delta x^\mu = w^\mu_\nu x^\mu = \sum_{\rho < \sigma} A^\mu_{(\rho \sigma)} w^{\rho \sigma}[/tex]
where the A is defined as
[tex]A^\mu_{(\rho \sigma)}=\delta^{\mu}_{\rho}x_\sigma - \delta^\mu_\sigma x_\rho[/tex]

If I do this calculation I always end up with a factor 3 on the right hand side times the desired result. Is this an error in the book? Or am I doing something wrong?
 
Physics news on Phys.org
The author is correct. Usually 'Aw' is written as '1/2 Aw' without specification that one indice is smaller than the other (A and w are antisymmetric so this is possible).

It's a bit baffling that the author defines the rotations like that though. I think the x's in the definition of A should be replaced by the metric 'g' that contracts with 'x' to get those expressions. That way iA would be a generator for the SO(4) vectorial representation.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 0 ·
Replies
0
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K