SciPost Submission Page
Ringdown in the SYK model
by Matthew Dodelson
Submission summary
| Authors (as registered SciPost users): | Matthew Dodelson |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2408.05790v2 (pdf) |
| Date submitted: | Feb. 19, 2025, 3:44 p.m. |
| Submitted by: | Dodelson, Matthew |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
We analyze thermal correlators in the Sachdev-Ye-Kitaev model away from the maximally chaotic limit. Despite the absence of a weakly curved black hole dual, the two point function decomposes into a sum over a discrete set of quasinormal modes. To compute the spectrum of modes, we analytically solve the Schwinger-Dyson equations to a high order in perturbation theory, and then numerically fit to a sum of exponentials using a technique analogous to the double cone construction. The resulting spectrum has a tree-like structure which is reminiscent of AdS black holes with curvature singularities. We present a simple toy model of stringy black holes that qualitatively reproduces some aspects of this structure.
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
-Clever use of the Krylov basis
-Interpolation away and towards the holographic limit
Weaknesses
Report
I think this paper should be published subject to an explanation of how one estimates the radius of convergence $\beta_0$. I could not find this explained in the manuscript, despite looking through it several times. Perhaps I missed something.
Requested changes
Please explain more prominently how $\beta_0$ is determined for this model.
Recommendation
Publish (surpasses expectations and criteria for this Journal; among top 10%)
Strengths
Weaknesses
Report
The main result is that the spectrum remains meromorphic, which is a very important statement. To some, this may have been expected and to some, a surprise. Regardless, the answer seems very clear and will provide a useful and invaluable benchmark in the future. Hence, the paper certainly eventually deserves to be published by SciPost. In order to make the presentation clearer, below, I suggest a number of small improvements to the text.
Requested changes
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It would be nice to explain more about the SYK model itself. For example, why we think of the maximal chaos limit as the `strongly coupled' limit, or, more accurately, as analogous to the large-N limit of higher dimensional models.
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I'm not sure that I like the aesthetics of the figures (e.g., the sizes of dots depending on the residue), but I do leave this up to the author to decide. Also, $d_n$ could be more clearly defined in Section 4 so that one doesn't have to search through the previous sections.
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Is there any sense in which one could claim that there are several branches of QNMs visible in the spectrum similar to the holographic calculation in [10]? Figure 3 kind of looks like that but it's hard to say.
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I think it would be very interesting to plot the spectral functions as a functions of real omega. I'm thinking of this along the lines of
- https://arxiv.org/abs/hep-th/0602059
- https://arxiv.org/abs/hep-ph/0602044
- https://arxiv.org/abs/1806.10997 Spectral functions themselves can teach us a lot about the transition of the physical spectrum from strong to weak coupling.
Recommendation
Ask for minor revision