Questions tagged [cpt-symmetry]
The cpt-symmetry tag has no usage guidance.
124
questions
3
votes
0
answers
101
views
Time Reversal symmetry, Quaternions, and spin-1/2 systems
When one has a system with no spin and time reversal symmetry, one can conclude that the Hamiltonian entries (in a particular basis, of course) must all be real. Can something be said about the ...
- 423
1
vote
0
answers
23
views
Question about the discrete symmetries of several fields
Short 4 questions:
Is free Klein-Gordon field possess some discrete symmetries? Is it invariant under $P$, $T$ separately?
Is free Proca field possess some discrete symmetries? Is it invariant under ...
- 73
1
vote
1
answer
59
views
Charge, Parity, and Time are considered when talking about symmetries in physics. What about Rotational symmetry?
I've seen Charge, Parity, and Time symmetries talked about, but how come never rotational symmetry? E.g. if the entire universe was rotated 90 degrees, would any physical phenomenon behave differently?...
- 1,090
0
votes
1
answer
89
views
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
0
votes
0
answers
263
views
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
answers
164
views
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
1
vote
1
answer
466
views
Regarding the action of Time reversal on Dirac spinors
I'm inquring about the difference between notions of time reversal found in Streater & Wightman's "PCT, Spin and Statistics, and All That", and this accepted answer from Chiral Anomaly. ...
- 1,117
2
votes
1
answer
218
views
Does the CPT theorem imply $CP=T$?
Does the CPT theorem imply $CP=T$?
That is, does it imply that the action of Charge Conjugation and Parity inversion on some representation of the Lorentz group, is the same as doing a time reversal?
...
- 1,117
0
votes
0
answers
45
views
Help me understand the CPT signatures of different physical quantities
I am an engineer and not a trained physicist, but still I am fascinated by symmetries and I want to understand them.
Specifically, in a paper ¹ I found the below table which covers a large number of ...
- 111
3
votes
0
answers
158
views
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 ...
1
vote
2
answers
116
views
$C$, $P$, $T$ symmetry of $O(3)$ non-linear sigma model
Consider the $O(3)$ nonlinear sigma model with topological theta term in 1+1 D: $$\mathcal{L}=|d\textbf{n}|^{2}+\frac{i\theta}{8\pi}\textbf{n}\cdot(d\textbf{n}\times d\textbf{n}).$$
The time reversal ...
- 868
2
votes
0
answers
244
views
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
views
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
vote
1
answer
68
views
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
votes
1
answer
157
views
How does Lorentz invariance link in with CPT symmetry?
I'm reading several articles on the relation between Lorentz symmetry (invariance under Lorentz transformations) and CPT symmetry; however, they all invoke high-level mathematics which I cannot ...
- 411