# Tagged Questions

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### What is the P-parity, T-parity and C-parity of graviton? Are these conserved in general curved space-time?

I'm curious about the P,T,C-parity of graviton? 1)Are these graviton's parities even or odd? 2)Is the C,P,T-parity alternatively conserved in Einstein gravity? And does the CPT theorem still hold ...
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### Understanding the Charge Conjugation Operator

I am trying to understand the charge conjugation operator. http://en.wikipedia.org/wiki/C_parity Because the operator is Hermitian, this seems to imply that there is a (possibly spontaneous?) ...
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### CPT invariance of Dirac equation

We know that Dirac equation is $$( i \partial _\mu \gamma ^\mu - m ) \psi ~=~0.$$ How can we show that Dirac equation is invariant under CPT transformation?
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### Equality of masses of particle and antiparticle

Usually we say that equality of masses of particle and antiparticle follows from CPT-theorem. But do we need it for showing this equality? The first method to show that is following. The equation ...
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### Intrinsic parity of particle and antiparticle with spin zero

I need to prove that the intrinsic parities of a particle and antiparticle with spin zero are the same. Can I prove that by an argument that operator of $P$-inversion commutes with charge conjugation ...
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### What is the definition of a charge-neutral operator?

What is the definition of a charge-neutral operator? I guess it means something like: it is invariant under charge conjugation. It that correct?
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### How to prove $(\gamma^\mu)^\dagger=\gamma^0\gamma^\mu\gamma^0$?

Studying the basics of spin-$\frac{1}{2}$ QFT, I encountered the gamma matrices. One important property is $(\gamma^5)^\dagger=\gamma^5$, the hermicity of $\gamma^5$. After some searching, I stumbled ...
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### Derivation of a gamma matrices identity

While studying Srednicki's book on quantum field theory, I encountered a particular identity that is of interest to me (equation 36.40): $$\mathcal{C}^{-1}\gamma^\mu\mathcal{C}=-(\gamma^\mu)^T$$ where ...
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### Charge conjugation in Dirac equation

According to Dirac equation we can write, $$\left(i\gamma^\mu( \partial_\mu +ie A_\mu)- m \right)\psi(x,t) = 0$$ We seek an equation where $e\rightarrow -e$ and which ...
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### Charge conjugation in Dirac equation

I need to know the mathematical argument that how the relation is true $(C^{-1})^T\gamma ^ \mu C^T = - \gamma ^{\mu T}$ . Where $C$ is defined by $U=C \gamma^0$ ; $U$= non singular matrix , $T$= ...
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### matter anti-matter world

let us suppose the gedanken experiment a man isolated into a room he ask if he is made of matter oder of antimatter could he set some experiments to see if he is made of matter or if he is made of ...
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### What makes *electric* charge special (wrt. CPT theorem)?

I'm wondering why the 'C' in CPT - charge conjugation - refers specifically to electric charge. Of course you could say that C is just defined as $e^+ \leftrightarrow e^-$... but there has to be ...