Technical question: vanishing of the cosmological constant in Randall Sundrum 1

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Discussion Overview

The discussion revolves around the vanishing of the cosmological constant in the Randall-Sundrum (RS) model, specifically model 1. Participants explore the relationship between brane tensions and the bulk cosmological constant, questioning how these lead to a zero 4D cosmological constant on the brane. The conversation is technical in nature, focusing on theoretical aspects of cosmology and higher-dimensional models.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about how the brane tensions and the integral of the 5D cosmological constant lead to a zero 4D cosmological constant, noting a mismatch in their calculations.
  • Another participant points out that the original RS papers do not explicitly state that the 4D cosmological constant is zero, suggesting that it may not be a trivial conclusion.
  • A later reply suggests that the 4D cosmological constant is automatically zero when considering Minkowski slices of AdS space, implying a different perspective on the issue.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of the 4D cosmological constant in the RS model. There are competing interpretations regarding the implications of the brane tensions and the integration of the bulk cosmological constant.

Contextual Notes

Some participants reference specific papers and reviews to support their points, indicating that the discussion may depend on interpretations of these sources. There is also mention of a potential factor of 2 mismatch in calculations, which remains unresolved.

nrqed
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This is a very technical question so I don't really expect someone to have the answer unless they have actually worked with or studied the RS models.


They say that the value of the brane tensions in model 1 (which are related to the bulk cosmological constant) are such that the 4D cosmological constant (on our brane) is zero.
I can't see how this comes about.

I probably misunderstand but the way i see it, there are two contributions to the 4D cosmological constant: the brane tension itself plus the integral over the fifth dimension of the 5D cosmological constant. But when I do the integral, the two terms do not cancel out (there is a mismatch by a factor of 2). I could show my calculation but I will wait to see if anyone can help.

Thanks
 
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PhysiSmo said:
Could you pinpoint us the original paper? Also, check out this review,

http://arxiv.org/abs/hep-th/0209261,

it's one of the best I've found for the subject.

Yes, this is a very good introduction. Unfortunately, it is not shown that the 4D cosmological constant in the original RS model is zero.

The two original RS papers are

http://arxiv.org/abs/hep-ph/9905221

and

http://arxiv.org/abs/hep-th/9906064

If I recall, in the first one they don't say explicitly that the 4D cosmological constant is zero.
In the second paper, they do say it and seem to imply that it follows trivially from the value of the brane tension and the constant appearing in the warp factor.
 
nrqed said:
This is a very technical question so I don't really expect someone to have the answer unless they have actually worked with or studied the RS models.


They say that the value of the brane tensions in model 1 (which are related to the bulk cosmological constant) are such that the 4D cosmological constant (on our brane) is zero.
I can't see how this comes about.

I probably misunderstand but the way i see it, there are two contributions to the 4D cosmological constant: the brane tension itself plus the integral over the fifth dimension of the 5D cosmological constant. But when I do the integral, the two terms do not cancel out (there is a mismatch by a factor of 2). I could show my calculation but I will wait to see if anyone can help.

Thanks

I think they're just looking at Minkowski slices of AdS space, so the 4d cosmological constant is automatically 0.
 

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