All Questions
Tagged with cpt-symmetry quantum-field-theory
51
questions
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43
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$C$-number ignored in charge conjugation
In Weinberg’s QFT V1, under equation 5.5.58, he says that an anticommutator ($c$-number) can be ignored when we exchange spinors, $\psi$ and $\bar{\psi}$. I cannot fully appreciate why we can ignore ...
- 619
1
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1
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128
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Charge conjugation is a symmetry for the quantized free Dirac action?
I am self-studying QFT on "A modern introduction to quantum filed theory" by Maggiore, and on page 95 he states: "For the free Dirac action, one immediately sees that C,P and T are ...
- 613
2
votes
0
answers
114
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Confused about square of time-reversal operator $T$
I am reading An Introduction to Quantum Field Theory by Peskin & Schroeder, and I am confused about what is the square $T^2$ of time reversal operator $T$.
My guess is that for $P^2$, $C^2$ and $T^...
- 613
2
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1
answer
113
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CPT invariance and Soft Theorems
I am reading the paper IR Dynamics and Entanglement Entropy, written by Toumbas and Tomaras and I have a question on using the CPT invariance of the QED $S$-matrix elements in order to derive the ...
- 3,992
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1
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89
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Is CPT symmetry a direct consequence of Special Relativity?
I'm wondering about the origin of $\mathcal{CPT}$ symmetry in the Standard Model. The Wikipedia entrance makes me understand it is a direct consequence of Special Relativity. Is it right?
- 147
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263
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What is relation between CPT invariance & Lorentz invariance, and why mass of particle/antiparticle is different in CPT violation?
(1) I read that CPT theorem can be proved with Lorentz invariance. Also, CPT violation implies Lorentz violation.
Is CPT invariance equivalent with Lorentz invariance, or just one-side direction holds?...
- 323
3
votes
0
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164
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Time-reversal transformation acts on the Weyl lagrangian with nonabelian gauge field
I would like to show time-reversal transformation acts on the Weyl lagrangian in the familiar 4 dimensional space-time.
My notation follows the same as Peskin QFT book, such as that of chapter 3. I ...
- 593
3
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158
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Why is CPT symmetry necessary to prove the spin-statistics theorem?
I was reading the Wikipedia article on the spin-statistics theorem. It has a section going through a "suggestive bogus argument", where they rotate products of fields. To show why it doesn't ...
2
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0
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244
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Is CPT a unitary symmetry or an antiunitary symmetry?
Is CPT a unitary symmetry or an antiunitary symmetry, such as the free Dirac theory of fermion $\psi$ in Chapter 3 of Peskin's QFT book?
Since
T is antiunitary symmetry,
P is unitary symmetry,
C is ...
- 4,336
3
votes
2
answers
1k
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Complex conjugation in time-reversal $T$ symmetry v.s. in charge conjugation $C$ symmetry
How is the complex conjugation $K$ of time-reversal symmetry $T$ differed by the complex conjugation of charge conjugation $C$? How are they differed from each other?
For instance, take the Dirac ...
- 593
1
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68
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Zee's book on QFT on the spin-1/2 state has $T^2=-1$, why not $T^2=+1$
In Zee's book on QFT, p.103, he showed that the spin-1/2 state has $T^2=-1$ by finding that the $T = UK$ has a matrix $U\propto \sigma_2$ and a complex conjugation $K$.
However, how do we know that we ...
- 593
0
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1
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252
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CPT invariance in Dirac Bilinears
I am currently working on exercise 3.7c of Peskin and Schroeder's An Introduction to Quantum Field Theory. The problem statement is:
Show that any Hermition, Lorentz scalar local operator built from $...
user261609
0
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answers
44
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Negative energy quanta vs antimatter approach
Consider 2 physical scenarios:
$t_{-1}$
$t_0$
$t_1$
Sc.1
electron and positron approached
electron and positron annihilated
photons emitted
Sc.2
electron is free
electron emits some photons
...
- 199
0
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1
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45
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Can one-electron world theory be revived if the Sakharov's conditions are completely met?
Regarding that people object about the matter antimatter balance in the one-electron world theory to discard it, can it be once more revived if the Sakharov's conditions are met so that the matter ...
- 1,268
1
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121
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Examples of the vacuum $| 0 \rangle$ break C, P, T symmetry?
Can the vacuum $| 0 \rangle$ of some QFT break C, P, T symmetry?
It could be that the QFT break C, P, T symmetry explicitly. Are there good examples?
p.s. The weak interaction breaks P explicitly ...
- 4,336