Does the Charge Conjugation Operator Affect Gamma Matrices Similarly?

Click For Summary
SUMMARY

The charge conjugation operator, denoted as C, transforms a Dirac spinor into its complex conjugate, specifically represented as C applied to the spinor matrix resulting in the complex conjugate of its components. In the context of gamma matrices from the Dirac equation, the relationship Cγ^a = -γ^aC holds true, indicating that the charge conjugation operator affects gamma matrices by introducing a negative sign. This transformation is consistent with the definitions found in standard texts such as Peskin & Schroeder, which describe charge conjugation as a unitary operator that exchanges particles with their antiparticles.

PREREQUISITES
  • Understanding of Dirac spinors and their properties
  • Familiarity with gamma matrices in quantum field theory
  • Knowledge of charge conjugation in particle physics
  • Basic concepts of unitary operators and their applications
NEXT STEPS
  • Study the properties of Dirac spinors in detail
  • Learn about the implications of charge conjugation on particle-antiparticle transformations
  • Explore the derivation of the relationship Cγ^a = -γ^aC in various contexts
  • Investigate the role of unitary operators in quantum mechanics and quantum field theory
USEFUL FOR

Physicists, particularly those specializing in quantum field theory, theoretical physicists studying particle interactions, and students seeking to deepen their understanding of charge conjugation and its effects on gamma matrices.

The black vegetable
Messages
22
Reaction score
0
TL;DR
What does the charge conjugation operator do mathematically?
I have in my notes the charge conjugation operator converts the spinnor into its complex conjugate ,

##
C\begin{pmatrix}
\varepsilon \\ \eta

\end{pmatrix}=\begin{pmatrix}
\varepsilon^{*}{} \\ \eta ^{*}

\end{pmatrix}##when applied to gamma matrix from dirac equation does it do the same? Trying to prove that

## C\gamma ^{a}=-\gamma ^{a}C ##

Any tips appreciated :)
 
Physics news on Phys.org
It depends a bit on the source from which you study, because there are several conventions around in the literature. The usual definition, as to be found in standard textbooks like Peskin&Schroeder they define charge conjugation on the Dirac spinor field by exchanging particles with anti-particles, i.e., if ##\hat{a}(\vec{p},\sigma)## are the annihilation operators for particles and ##\hat{b}(\vec{p},s)## those of antiparticles you define the unitary charge-conjugation operator via
$$\hat{C} \hat{a}(\vec{p},\sigma) \hat{C}^{\dagger}=\hat{b}(\vec{p},\sigma).$$
Using the properties of the mode functions in the mode decomposition of the Dirac-field operator this gives
$$\hat{C} \hat{\psi}(x) \hat{C}^{\dagger}=-\mathrm{i} \left (\bar{\psi} \gamma^0 \gamma^2 \right)^{\text{T}}$$
and
$$\hat{C} \overline{\psi}(x) \hat{C}^{\dagger}=-\mathrm{i} \left (\gamma^0 \gamma^2 \psi \right)^{\dagger}.$$
 
  • Like
Likes   Reactions: The black vegetable
Okay thanks, was thinking I could do it purely by matrices but will have to look more into it as I'm not familiar with some other terms you used :)
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 13 ·
Replies
13
Views
11K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K