Questions tagged [cpt-symmetry]
The cpt-symmetry tag has no usage guidance.
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Magnetic monopole in CPT universe model
I've recently read this paper CPT universe, and a thought came into my mind.
Is it possible to discuss magnetic monopole based on this CPT universe model?
This paper points out that some mysterious ...
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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 ...
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I want to know about origin of non-Hermitian quantum field theory model having two complex scalar fields $\phi_1$ and $\phi_2$
In the paper Symmetries and conservation laws in non-Hermitian field theories by Jean Alexandre, Peter Millington, and Dries Seynaeve, Phys. Rev. D 96, 065027 the authors use this Lagrangian:
$$ L = ...
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Thermodynamics of T-symmetry violation
Physics is mostly time reversible. But certain nuclear interactions violate this T symmetry.
With T-symmetry a system at maximum entropy has no "arrow of time". Thus a video of the system ...
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Magnetic Monopoles and Its Antimatter and Mirror Particle Counterparts [closed]
I'm trying to understand how magnetic monopoles and how its potential mirror and antiparticle counterparts would behave. So according to the modified lorentz force law
$$\vec{F}=q_e\left(\vec{E}+\frac{...
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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 ...
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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^...
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Are Hamiltonians CPT invariant?
I'm confused by the CPT theorem. It states (more or less) that a Lorentz invariant quantum field theory needs to be CPT invariant. But what does it actually mean for a QFT to be CPT invariant? It ...
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Non-Hermitian PT-symmetric Interacting Hamiltonian with Real Spectra
The following hamiltonian is $\mathcal{PT}$-symmetric $$\mathcal{H} = -J \sum_{j = 1}^{2N} [ 1 + (-1)^j \delta ] [ c^{\dagger}_{j} c_{j+1} + h.c. ] + \imath \gamma \sum_{j = 1}^{2N} (-1)^j c^{\dagger}...
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Are there theorems from electromagnetism that are a consequence of $C$, $P$ or $T$ invariance?
It's well known that classical electrodynamics is $C$, $P$ and $T$ invariant. For example, see this question Maxwell's equations and $C$, $P$, $T$ Symmetry. Are there theorems within CED that are a ...
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Is really hermiticity necessary to be a physical observable? What about larger class of operators like PT invariant operators or pseudo hermitian one?
It's really necessary for an observable represented by an operator acting in a Hilbert space to be hermitian?
It's known that not only hermitian operators have real eigenvalues and that also normal ...
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Is $CPT$ Symmetry already broken?
i came up this paper recently: https://doi.org/10.1140/epjc/s10052-020-08549-9 it describes the "CPT violation with decoherence effects" by Neutrinos.
This means CPT Symmetry is broken? And ...
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Can you tell wavefunction's chirality by looking at it?
I recently learned, that:
Helicity is a combination of particle's "rotation"
(Spin) and direction of it's motion.
The motion is relativity-dependant, and so is helicity.
Chirality ...
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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 ...
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Enlarging the action of $C$, $P$ and $T$
I am now studying QFT using Schwartz's book, and I am going through the part discussing about how the charge conjugation, parity, and time-reversal operator acting on various object should look like. ...
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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 ...
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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 ...
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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?...
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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?
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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?...
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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 ...
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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. ...
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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?
...
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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 ...
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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 ...
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$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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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