Does CPT Symmetry Apply to a Mirror World with Reversed Properties?

  • Context: Graduate 
  • Thread starter Thread starter questionner
  • Start date Start date
  • Tags Tags
    Cpt symmetry Symmetry
Click For Summary

Discussion Overview

The discussion revolves around the application of CPT symmetry to a hypothetical mirror world where properties such as parity and time are reversed. Participants explore the implications of this symmetry on the laws of physics in such a world, questioning whether charge would remain unchanged and how different interactions might manifest.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that if a mirror world has reversed parity and time, then CPT symmetry suggests that the same physics laws would apply, provided charge is also reversed.
  • Others argue that without the charge reversal (C), the resulting world would differ significantly, particularly in how weak interactions manifest.
  • A participant questions why we do not observe "copy-electrons" in processes where real electrons are produced, suggesting a need for clarity on which laws of physics are being altered.
  • Another participant expresses curiosity about the implications of reversing only one of C, P, or T on a magnetic dipole and what interactions might be violated as a result.
  • One participant notes that if different physics laws apply in the mirror world, then the assumption about charge remaining unchanged leads to uncertainty about the outcomes.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are multiple competing views regarding the implications of CPT symmetry and the nature of interactions in the proposed mirror world.

Contextual Notes

Limitations include assumptions about the nature of the mirror world and the specific laws of physics that may or may not apply. The discussion does not resolve the complexities of how interactions would differ based on the reversal of symmetries.

Who May Find This Useful

This discussion may be of interest to those exploring theoretical physics, symmetry principles, and the implications of hypothetical scenarios in particle physics.

questionner
Messages
7
Reaction score
1
TL;DR
Given a copy of our world with parity and time reversed, should charge remain the same if different physics law govern the copy world?
Say we have a copy of our world, but with the "parity" and "time" reversed. (For example, the mirror world from the novel "Alice Through the Looking Glass".)

If the "charge" is also reversed, then due to the CPT symmetry, the same physics law would apply to the mirror world, right?

If we assume that different physics law are applied in the mirror world, then does it mean that the "charge" should remain unchanged from our world?
 
Physics news on Phys.org
Since PT is not a symmetry you need C in addition to get a precise copy of our world ;-). Without also applying C you get another world, where the weak interaction looks different than in ours.
 
  • Like
Likes   Reactions: questionner
vanhees71 said:
Since PT is not a symmetry you need C in addition to get a precise copy of our world ;-). Without also applying C you get another world, where the weak interaction looks different than in ours.
Yeah, so since the mirror world in the novel "Through the looking glass" seemed to have different physics law compared to ours, and since parity and time seems to be reversed, then charge should remain same as our world, right? :)
 
questionner said:
Say we have a copy of our world
How does this work? Why don't we see copy-electrons pair produced in the same processes where we see real electrons pair produced?

It sounds like you want to suspend some but not all of the laws of physics and see what happens. That's fair, but you need to be very., very clear about what you are keeping and what you are throwing away.
 
  • Like
Likes   Reactions: vanhees71
Vanadium 50 said:
How does this work? Why don't we see copy-electrons pair produced in the same processes where we see real electrons pair produced?

It sounds like you want to suspend some but not all of the laws of physics and see what happens. That's fair, but you need to be very., very clear about what you are keeping and what you are throwing away.
I was just simply thinking of a hypothetical world, like people saying the world with all CPT reversed have the same physics as our world.

Another thing I am curious about is that a magnetic dipole with only one of C or P or T reversed is different from the original one. What interaction is violated here?
 
questionner said:
If we assume that different physics law are applied in the mirror world, then does it mean that the "charge" should remain unchanged from our world?
If you assume that, all bets are off. Anything could happen.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 22 ·
Replies
22
Views
2K
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 34 ·
2
Replies
34
Views
5K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K