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From Rindler Fluid to Dark Fluid on the Holographic Cutoff Surface
by Rong-Gen Cai, Gansukh Tumurtushaa, Yun-Long Zhang
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Submission summary
| Authors (as registered SciPost users): | Yun-Long Zhang |
| Submission information | |
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| Preprint Link: | scipost_202010_00031v1 (pdf) |
| Date submitted: | 2020-11-01 00:24 |
| Submitted by: | Zhang, Yun-Long |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | 4th International Conference on Holography, String Theory and Discrete Approach in Hanoi (STRHAN2020) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
As an approximation to the near horizon regime of black hols, the Rindler fluid was proposed on an accelerating cutoff surface in the flat spacetime. The concept of the Rindler fluid was then generalized into a flat bulk with the cutoff surface of the induced de Sitter and FRW universe, such that an effective description of dark fluid in the accelerating universe can be investigated.
Current status:
Reports on this Submission
Report #1 by Anonymous (Referee 2) on 2020-11-15 (Invited Report)
- Cite as: Anonymous, Report on arXiv:scipost_202010_00031v1, delivered 2020-11-14, doi: 10.21468/SciPost.Report.2192
Strengths
1- ambitious
2- attacking a very relevant problem
3- concise
Weaknesses
1- theoretical derivation quite speculative
2- idea not too innovative (cf Verlinde's work)
3- motivation of the framework disputable
Report
The paper attacks the fundamental problem of dark matter and dark energy following the original idea of Verlinde and building on it. The presentation is adequate. My major complaint is about the formal derivation and motivation for Eq(1)-(2) which constitute the basis of the framework.
Looking at equation (1) it seems that the idea is to embed our world (the 4D brane) in a 5D spacetime and assume that dark matter comes from the matter degrees of freedom in the extra dimension. Despite this seems quite an old idea (cf. Randall-Sundrum type models), its motivation and implementation is not so robust. Eg. Is there an action in 5D from which Eq.(1) can be derived?
Also, in principle, the stress tensor contribution coming from the extra dimension could be more complicated that what used in Eq(2) and it is strongly dependent on the ''coupling'' between our 4dimensional world and the fields living in the 5dimensional bulk. What does motivate such a simple form?
Is this related to the idea that DM comes simply from the gravitational dynamics and not from any hidden matter sector couple to the standard model?
In summary, I urge the authors to introduce better the model and the ideas behind the theoretical formulation. Once Eq(1)-(2) are accepted, the computations and the paper flow quite nicely, but those are key points whose assumptions and derivation have to be explained in more detail for the Reader not totally familiar with the topic.
Requested changes
1- justify and introduce better the theoretical background, the assumptions and the physical ideas behind equations 1 and 2.