Should the Special Relativity Principle be Reduced to a Tautology?

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Discussion Overview

The discussion centers on the nature of the Special Relativity (SR) principle, particularly whether it should be considered a tautology and how it relates to various physical laws and potential violations of Lorentz invariance. Participants explore theoretical implications, experimental considerations, and the relationship between SR and General Relativity, as well as specific phenomena such as kaon-antikaon decay.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that the relativity principle can be reduced to a tautology, categorizing physical laws into those valid in all inertial frames and those that are not.
  • Others argue that Special Relativity is merely a locally-valid approximation to General Relativity, questioning the relevance of spatially compact spacetimes in real-world applications.
  • A participant emphasizes that searches for violations of Lorentz invariance focus on local Lorentz invariance, suggesting that the implications of spatially compact spacetimes may not apply to our universe.
  • There is interest in the asymmetric decay of kaons and antikaons, with some suggesting this may indicate a preferred frame, while others discuss the implications of CP-symmetry violations within the Standard Model.
  • Some contributions explore the idea that Lorentz symmetry violations could arise from spontaneous symmetry breaking, suggesting that asymmetries may not reflect fundamental laws but rather specific vacuum states influenced by historical events.
  • One participant presents a conceptual framework for understanding spacetime, arguing against the notion of additional dimensions and proposing a unified view of spacetime as a single entity.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of the relativity principle, the relevance of spatially compact spacetimes, and the implications of kaon-antikaon decay. The discussion remains unresolved, with no consensus reached on these topics.

Contextual Notes

Limitations include the dependence on specific definitions of spacetime and the unresolved nature of the proposed experiments regarding Lorentz invariance violations. The discussion also highlights the complexity of the relationship between SR and General Relativity.

Perspicacious
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You have probably noticed that the full force of Poincaré's relativity principle isn't necessary to derive the Lorentz transformation and the essence of special relativity:

http://www.everythingimportant.org/relativity/
http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000043000005000434000001
http://arxiv.org/PS_cache/physics/pdf/0302/0302045.pdf

You are also very likely aware of the well-known fact that spatially compact spacetimes break global Lorentz invariance and define absolute inertial frames of reference:
http://groups.google.com/group/sci.physics.research/msg/e19ac8581a6148f2

Since SR is easily generalized so as to include this interesting class of spacetimes, it's reasonable, then, to amend the relativity principle also. I propose that it be reduced to a tautology.

Proposition: All physical laws can be divided into two categories. The two great divisions are the laws that are true in all inertial frames of reference and those that aren't.

There are many conjectures, proposed experiments and searches for possible violations of Lorentz invariance. What are the possibilities? Is there a catalogue of current conjectures? Let me list a few ideas and concepts based on possible laws from the second category.

1. Superluminality (a popular favorite)
2. Perfect matter-antimatter symmetry
3. Object length dependence on frame of reference

I'm especially interested in the observed asymmetry between kaons and antikaons and whether or not their asymmetric decay is a consequence of a preferred frame. Has a test for this possibility been seriously considered?
 
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Special Relativity is only a locally-valid approximation to General Relativity.

So a spatially compact but flat spacetime is an interesting theoretical idea but isn't really relevant our real spacetime which isn't flat.

Searches for violations of Lorentz invariance are for violations of local Lorentz invariance.
 
DrGreg said:
A spatially compact but flat spacetime is an interesting theoretical idea but isn't really relevant our real spacetime which isn't flat.
My links to spatially compact spacetimes are not limited to those that are flat. My other thread, The Black Hole in a Spatially Compact Spacetime, opens with this quote:

Thus in Friedmann–Lemaıtre universes, (i) the expansion of the universe and (ii) the existence of a non–trivial topology for the constant time hypersurfaces both break the Poincare invariance and single out the same “privileged” inertial observer who will age more quickly than any other twin: the one comoving with the cosmic fluid – although aging more quickly than all her traveling sisters may be not a real privilege!
A link to that paper, which contains the foregoing statement, is listed in my references.

DrGreg said:
Searches for violations of Lorentz invariance are for violations of local Lorentz invariance.
My question about asymmetric kaon-antikaon decay is precisely in the context of a possible violation of local Lorentz invariance.
 
Perspicacious said:
I'm especially interested in the observed asymmetry between kaons and antikaons and whether or not their asymmetric decay is a consequence of a preferred frame.
As I understand it, this asymmetric behavior of kaons is a violation of CP-symmetry, but this is permitted in the Standard Model, which exhibits the larger CPT-symmetry and which is also Lorentz-symmetric. There are apparently some extensions of the Standard Model that allow for Lorentz symmetry to be violated, although I think the symmetry is broken by spontaneous symmetry breaking which means the theory would have been symmetric in the era when the forces were unified, and the symmetry was broken by a random decay to different vacuum state. So if I'm understanding this right, there wouldn't be any asymmetry in the fundamental laws of physics, just in the particular vacuum state which our region of the universe has, which was fixed by contingent events in the past. This article discusses such lorentz-symmetry-violating extensions of the Standard Model in more detail:

http://physicsweb.org/articles/world/17/3/7
 
Perspicacious said:
Since SR is easily generalized so as to include this interesting class of spacetimes, it's reasonable, then, to amend the relativity principle also. I propose that it be reduced to a tautology.

Proposition: All physical laws can be divided into two categories. The two great divisions are the laws that are true in all inertial frames of reference and those that aren't.

There are many conjectures, proposed experiments and searches for possible violations of Lorentz invariance. What are the possibilities? Is there a catalogue of current conjectures? Let me list a few ideas and concepts based on possible laws from the second category.

1. Superluminality (a popular favorite)
2. Perfect matter-antimatter symmetry
3. Object length dependence on frame of reference

I'm especially interested in the observed asymmetry between kaons and antikaons and whether or not their asymmetric decay is a consequence of a preferred frame. Has a test for this possibility been seriously considered?

The link provided by JesseM :http://physicsweb.org/articles/world/17/3/7

Has a sentence:An elementary particle in the presence of one of these relic fields would then experience interactions that have a preferred direction in space-time. In particular, there could be preferred directions in 3D space in any fixed reference frame, such as an Earth-based laboratory.

Emphasis on the last part relative to 3-D space.

The fundamental problem lay within the notion of 3-D + '1D' to complete the 4-D spacetime.

Its not that there is an added '+' dimension, I believe the fundamental problem lay in that Spacetime is not linear in any way all wrapped into the same bundle?..for instance we should not be looking for the 3-D connective "TIME" componant in Einsteins Relativity, it should be stated as a single spacetime, but within the context of : 4-D spacetime = 3-D in 1.

Thus, the continuation of all dimensional extensions are embedded 'within' a single 'space-time-frame', the "1" is not an added dimension branching off into hidden extensive area's such as 3+1..4+1..5+1..etc..etc?

Like a labourer who has to 'mix' the contents of sand..cement..water into "one", to produce the concrete for a building foundation, one can see the beauty of the understanding that 2D+1D, 3D+1D,4D+1D all produce a symmetry breaking (the plus 1 is what breaks the symmetry mold), but 3Din 1D or 4-D in 1D..etc..etc does not break this mold at all, 3-Dimensional matter is "in", ONE-DIMENSION, the space-time-frame.

The notion of 3-D matter, does not need the extra added componant of "plus1" in any context, by its very existence, it is already within the "1" frame.
 
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