Issue about CPT

  • Thread starter franoisbelfor
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In summary, the CPT theorem states that you can take any valid process and apply C, P, and T (reverse spins and replace all particles with antiparticles) and you ALWAYS get a valid process.
  • #1
franoisbelfor
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What is wrong in this reasoning about CPT symmetries?

Spatial inversion P preserves spin and inverses velocity. (See wikipedia,
at http://en.wikipedia.org/wiki/P-symmetry )

Motion or time inversion T inverses both spin and velocity (obvious, see also wikipedia,
at http://en.wikipedia.org/wiki/T-symmetry ).

Now, charge conjugation C preserves chirality. ( http://en.wikipedia.org/wiki/Charge_conjugation )
That means that either spin and velocity are both inverted or they are both preserved.

But: In either of these two cases, C cannot be equal to TP.
Now, C=TP is a deep theorem in physics!
What is wrong in this argument chain?


François
 
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  • #2
Nobody really says that C=PT, not in the sense that you get identical results from applying these two symmetries.

In a classical world, C, P, and T are all symmetries by themselves. Meaning, you can take a physical process or an area of spacetime and apply C or P or T and you get a new valid process.

In a quantum world, P is not a symmetry, because it takes valid weak-interaction processes into invalid processes. It is maximally violated by the weak interaction. CP is a lot better. The CPT theorem essentially states that you can take any valid process, apply C, P, and T (reverse spins and replace all particles with antiparticles), and you ALWAYS get a valid process.
 
  • #3
hamster143 said:
Nobody really says that C=PT, not in the sense that you get identical results from applying these two symmetries.

...

The CPT theorem essentially states that you can take any valid process, apply C, P, and T (reverse spins and replace all particles with antiparticles), and you ALWAYS get a valid process.

Oh, I understand. I have read so often that CP and T are either both broken or both
conserved that I thought that this means that CP equals T. Ok, that is wrong.
Thanks!

François
 

1. What is CPT?

CPT stands for Current Procedural Terminology and is a medical code set used to report medical, surgical, and diagnostic procedures and services to insurance companies for reimbursement purposes.

2. Who uses CPT codes?

CPT codes are used by healthcare providers, such as physicians, nurses, and other medical professionals, as well as insurance companies and government agencies.

3. How often are CPT codes updated?

CPT codes are updated once a year by the American Medical Association (AMA) to reflect changes in medical practices and technology.

4. Can CPT codes be used internationally?

While CPT codes are primarily used in the United States, they have been adopted in some other countries, such as Canada, and are also used in conjunction with other code sets in international medical coding systems.

5. Are there any additional resources for learning about CPT codes?

Yes, in addition to the official CPT code book published by the AMA, there are also online resources and training courses available to help healthcare professionals learn and understand CPT codes.

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