Questions tagged [cpt-symmetry]
The cpt-symmetry tag has no usage guidance.
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CPT theorem and the weak interaction
I am trying the understand how the weak interaction obeys CPT symmetry. My understanding is that, under a CPT transformation, the Lagrangian for the Standard Model should be invariant, and thus the ...
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C, P and T transformations of $\phi$ that preserves symmetry
I have a series of exercises regarding C, P and T symmetry but I am not really sure how to start with the problems. If anyone could help me with one of the problems, or show me a few example problems ...
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What is CPT, really?
The naive statement for the "CPT theorem" one usually finds in the literature is "relativistic theories should be CPT invariant". It is clear that this statement is not true as written, e.g. ...
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Decomposing the $\mathcal{N} = 4$ massless graviton supermultiplet
I'm trying to solve the following exercise:
Construct the physical states of the $\mathcal{N} = 4$ massless graviton supermultiplet, starting from a Clifford vacuum of helicity $λ_0 = 0$.
Decompose ...
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Electric dipole moment (EDM) and CP violation
It's well known that a non-zero value for the electric dipole moment (EDM) would imply CP violation. If we consider the interaction Hamiltonian of an EDM $d$ with an electric field $\vec{E}$,
$$
H = -...
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QED $PC$ conservation
I'm trying to prove that the QED Lagrangian
$$\mathscr{L}=\bar{\psi}(i\!\!\not{\!\partial}-m)\psi - \frac{1}{4}F^{\mu\nu}F_{\mu\nu} - J^\mu A_\mu$$
Is invariant under P and C. The two fields transform ...
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Why isn't EM radiation from an accelerated charge time reversible?
Let a charge $q$ enter a constant magnetic field $B$ at 90 degrees, hence radiating EM energy-momentum and spiraling inwards to some point as it slows down. Time reversing this, including the current ...
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Why aren't black holes antimatter fountains?
As I understand it, nothing can escape a black hole because the only worldlines leading 'out' from the event horizon point backwards in time.
As I understand it, antimatter is time-reversed ordinary ...
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Does it mean time reverses if all particles were antiparticles and vice versa?
First of all, I'm not major in physics and the question might seems stupid, as I'm layman studying for my self-interest and I really don't know much about it. I only think it might open some ...
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Does charge conjugation symmetry sit in the Lorentz group?
We know the Lorentz group is $O(3,1)$ in 4 dimensional spacetime.
We know that there are 4 disconnected components in Lorentz group $O(3,1)$, and https://math.stackexchange.com/q/2204349/
$$\pi_0(\...
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Are all processes time/CPT-reversible, e.g. measurement, stimulated emission, state preparation, Big Bang?
"The CPT theorem says that CPT symmetry holds for all physical phenomena, or more precisely, that any Lorentz invariant local quantum field theory with a Hermitian Hamiltonian must have CPT symmetry." ...
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Does the CPT theorem hold for all spacetime dimensions?
I can't find any reference which mentions the dependence of the theorem on spacetime dimension, but it would be very interesting to know what if any it has!
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CPT transformation for bilinears
In the page 5 of the document 'CPT Symmetry and Its Violation' by Ralf Lehnert (https://core.ac.uk/download/pdf/80103866.pdf), appears a discussion about how the spin-statistics theorem applies to the ...
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Arrow of time and CPT symmetry
It's been a few years since my physics degree. But I've been wondering: if you look at pictures of collisions at CERN, isn't it obvious which way time flows - simply on a probability basis? The ...
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Mathematical representation of Symmetry Transformation
Consider a general Hamiltonian that is made up of three terms
$\mathcal{H}$ = term I + term II + term III .
Suppose the combination of charge conjugation and parity (CP) is a symmetry of this ...
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