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Higher spin swampland conjecture for massive AdS$_{3}$ gravity
by R. Sammani, E. H Saidi
This is not the latest submitted version.
Submission summary
| Authors (as registered SciPost users): | Rajae Sammani |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2406.09151v1 (pdf) |
| Date submitted: | 2024-07-26 16:36 |
| Submitted by: | Sammani, Rajae |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
In this paper, we show that a possible version of the swampland weak gravity conjecture for higher spin (HS) massive topological AdS$_{3}$ gravity can be expressed in terms of mass $M_{hs}$, charge $Q_{hs}$ and coupling constant $g_{hs}$ of 3D gravity coupled to higher spin fields as $M_{hs} \leq \sqrt{2}$ $Q_{hs}$ $g_{hs}$ $M_{Pl}$. The higher spin charge is given by the $SO(1,2)$ quadratic Casimir $Q_{hs}^{2}=s\left (s-1\right) $ and the HS coupling constant by ${\large g}_{hs} ^{2}=2/\left (M_{Pl}^{2} l_{AdS_{3}}^{2}\right )$ while the mass expressed like $\left( l_{AdS_{3}} \text{M}_{hs}\right) ^{2}$ is defined as $ \left (1+\mu l_{AdS_{3}} \right ) ^{2} s \left ( s-1 \right ) +[1- \left ( \mu l_{AdS_{3}} \right ) ^{2} \left ( s-1 \right ) ]$.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Current status:
Reports on this Submission
Strengths
1- Interesting idea on a topic of current interest
Weaknesses
1- A conjecture that depends on a previous conjecture
2- Unclear argument for identification of charge
Report
This paper considers the possibility that the weak gravity conjecture might apply to higher spin theories as well. This is an interesting idea worth considering.
However, I am not quite sure whether the authors provided convincing evidence. Formula (4.4) is a conjecture presented in (16) of Ref.[4], based on the spin-two results in [37,38] and on some other papers (1106.5141, 1107.0915, 1107.2063). As the other referee is pointing out, it would be beneficial to review critically the evidence behind this conjecture, before formulating a further conjecture that depends upon it.
Moreover, after massaging this into (4.10), the authors identify that the two factors are the coupling constant and the charge. What is the evidence for this identification? If we are just being guided by what we would like to be true, namely (4.1), then it seems to me that we are not really providing an argument.
In my opinion, it would be important to provide some independent argument (not based on what we would like to prove) that $j(j+1)=s(s-1)$ can indeed be considered a charge. Such evidence might be provided for example by the behavior of higher spin black holes.
Requested changes
1- Review of why (4.4) might be true
2- Independent argument to justify why $s(s-1)$ can be thought of as charge
Recommendation
Ask for major revision
Report
The authors conjecture a possible extension of the Weak Gravity Conjecture (WGC) to higher spin massive topological gravity on AdS3 backgrounds by considering the decay of the higher spin generalization of BTZ black holes in these theories. To develop their conjecture, they need to identify the appropriate states that conjecturally mediate the discharge of these black holes, and discuss their mass, charge, and coupling. They argue for this identification by using a Chern-Simons formulation of higher-spin AdS3 gravity, supplemented by a mass term.
The questions studied in this paper are relevant for extending the applicability of one of the most consequential and well-studied conjectures in the swampland program, and are thus a valuable addition to the swampland literature.
Before recommending the paper for publication, I would like to ask a few clarification questions to the authors:
1. Could the authors provide a short self-contained review of the massive formulation the higher-spin theory? Specifically, it would be beneficial for the reader if the authors could review the properties of the action (4.3) and, in particular, how formula (4.4) is obtained. This is particularly relevant in light of the fact that (4.4) is the crucial starting point for their derivation of the inequalities in section 4.1.
2. It would also beneficial if the authors could expand their discussion in section 5 by commenting on the differences between the topological nature of the theory they are considering, with local degrees of freedom added by the mass deformation, with the more standard setup of the WGC with local U(1) degrees of freedom.
3. The authors mention in the introduction that for AdS3 weak forms of the WGC are not enough to ensure black hole decay, thus requiring a lattice version of the WGC. Is it obvious that this same argument directly applies to the higher-spin case? Could it be that the self-interacting particle condensates might not form in the class of theories the authors are considering? It can be helpful for the readers if the authors could expand on this point, discussing possible difference that might arise in higher-spin theories.
Recommendation
Ask for minor revision
Author: Rajae Sammani on 2024-11-01 [id 4925]
(in reply to Report 1 on 2024-10-27)Please see the attached file for clarifications on the points raised in the report.
Attachment:
1Nov-To-Referee-SciPost.pdf