What is the Role of Conformal Symmetry in De Sitter Relativity?

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Discussion Overview

The discussion centers on the role of conformal symmetry in de Sitter relativity, particularly in the context of quantum gravity. Participants explore theoretical implications, observational evidence, and the relevance of conformal symmetry at ultra-high energy densities.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that de Sitter special relativity can predict the cosmological constant and address the cosmic coincidence problem, especially at ultra-high energy densities.
  • Others argue that conformal symmetry, while not exact at low energies, becomes significant at high energy densities, suggesting that physics may become conformal invariant near the Planck energy.
  • A participant expresses skepticism about the observational data from MAGIC, questioning its robustness and suggesting that alternative explanations for delays in gamma-ray flares may exist.
  • There is mention of Giovanni Amelino-Camelia's perspective that recent work in quantum gravity phenomenology may allow for experimental tests of quantum gravity theories.
  • Some participants reference various studies and papers to support their claims, indicating a reliance on independent analyses to bolster arguments regarding the limits of observational data.
  • There are references to competing theories in quantum gravity, such as loop quantum gravity and string theory, with some participants suggesting that certain approaches may be less viable.

Areas of Agreement / Disagreement

Participants express a mix of agreement and skepticism regarding the implications of conformal symmetry and the observational evidence presented. Multiple competing views remain, particularly concerning the validity of specific data and the interpretation of quantum gravity theories.

Contextual Notes

Limitations include the dependence on specific observational data and the unresolved nature of the mathematical implications of conformal symmetry in high-energy contexts. The discussion does not reach a consensus on the validity of the claims made.

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De Sitter Relativity: a New Road to Quantum Gravity
http://www.springerlink.com/content/g6275857g60638h8/fulltext.pdf

...When applied to the whole universe, de Sitter special relativity is able to predict,from the current matter content of the universe, the value of cosmological constant (lambda). It gives, furthermore,an explanation for the cosmic coincidence problem.When applied to study the propagation of ultra-high energy photons, it gives a good estimate for the recently observed delay in high energy gamma-ray flares coming from the center of the galaxy Markarian 501. If this delay is a manifestation of the small-scale fluctuations in the texture of spacetime, predicted to exist at very high energies, de Sitter relativity can be seen as a new paradigm to approach quantum gravity.....

...Even though conformal symmetry is not an exact symmetry at low energies, according to de Sitter special relativity it naturally becomes the relevant symmetry at ultra-high energy densities. In fact, the higher the energy density, the higher the value of lambda, the higher the importance of conformal symmetry. Near the Planck energy, the local value of lambda will be very large, and the local de Sitter space will approach a conespacetime, which is transitive under proper conformal transformations only. Under such extreme conditions, physics becomes conformal invariant, and the proper conformal current will be conserved...
 
Physics news on Phys.org
This is the source study?: http://arxiv.org/abs/0708.2889

Seems to underly a lot of the observational portion of the piece. The thinking seems sound at high energies, but I don't find the MAGIC data convincing, although I respect their free admission of possible interference.

This seems like a lot to justify on the basis of choosing a possible source of delay when others with less global implications may well exist.
 
Frame Dragger said:
This is the source study?: http://arxiv.org/abs/0708.2889

Seems to underly a lot of the observational portion of the piece. The thinking seems sound at high energies, but I don't find the MAGIC data convincing, although I respect their free admission of possible interference.

This seems like a lot to justify on the basis of choosing a possible source of delay when others with less global implications may well exist.

of the first post, yes.



but of the second post:

http://star.herts.ac.uk/~granot/papers/GRB090510_Nature.pdf
or
http://arxiv.org/ftp/arxiv/papers/0908/0908.1832.pdf

...We stress here that our most conservative limits, a and b in Table 1,
rely on very different and largely independent analysis, yet still give a
very similar limit, of \xi1>.1.2. This lends considerable support to this
result, and makes it more robust and secure than for each of the methods separately....




-----------------------
...Giovanni Amelino-Camelia of the University of Rome La Sapienza believes that the latest work points to the coming of age of the field of quantum gravity phenomenology, with physicists finally able to submit theories of quantum gravity to some kind of experimental test. "Nature, with its uniquely clever ways, might have figured out how to quantize space–time without affecting relativity".....


-----------------------
loop quantum gravity, string theory, dead.
 
Last edited by a moderator:
yoda jedi said:
of the first post, yes.



but of the second post:

http://star.herts.ac.uk/~granot/papers/GRB090510_Nature.pdf

We stress here that our most conservative limits, a and b in Table 1,
rely on very different and largely independent analysis, yet still give a
very similar limit, of \xi1>.1.2. This lends considerable support to this
result, and makes it more robust and secure than for each of the methods separately.

Fair enough, I suppose it's just up against stiff competiton. ;)
 
Last edited by a moderator:
Frame Dragger said:
Fair enough, I suppose it's just up against stiff competiton. ;)



...laughs...

well... we have to progress
 
....still stand, Elze.


Zloshchastiev dead.


Wang, who knows...




Svetlichny, maybe dead.

cos,http://arxiv1.library.cornell.edu/PS_cache/quant-ph/pdf/0410/0410230v1.pdf

...At the Planck scale, nonlinear effects may be of the same order of magnitude
as linear ones...
 
Last edited by a moderator:

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