SciPost Submission Page
Visions in Quantum Gravity
by Luca Buoninfante, Benjamin Knorr, K. Sravan Kumar, Alessia Platania, Damiano Anselmi, Ivano Basile, N. Emil J. Bjerrum-Bohr, Robert Brandenberger, Mariana Carrillo González, Anne-Christine Davis, Bianca Dittrich, Paolo Di Vecchia, John F. Donoghue, Fay Dowker, Gia Dvali, Astrid Eichhorn, Steven B. Giddings, Alessandra Gnecchi, Giulia Gubitosi, Lavinia Heisenberg, Renata Kallosh, Alexey S. Koshelev, Stefano Liberati, Renate Loll, Leonardo Modesto, Paulo Moniz, Daniele Oriti, Olga Papadoulaki, Jan M. Pawlowski, Roberto Percacci, Lesław Rachwał, Mairi Sakellariadou, Alberto Salvio, Kellogg Stelle, Sumati Surya, Arkady Tseytlin, Neil Turok, Thomas Van Riet, Richard P. Woodard
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Damiano Anselmi · Benjamin Knorr · Alessia Platania |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2412.08696v2 (pdf) |
| Date accepted: | July 8, 2025 |
| Date submitted: | Feb. 25, 2025, 6:06 p.m. |
| Submitted by: | Alessia Platania |
| Submitted to: | SciPost Physics Community Reports |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
To deepen our understanding of Quantum Gravity and its connections with black holes and cosmology, building a common language and exchanging ideas across different approaches is crucial. The Nordita Program "Quantum Gravity: from gravitational effective field theories to ultraviolet complete approaches" created a platform for extensive discussions, aimed at pinpointing both common grounds and sources of disagreements, with the hope of generating ideas and driving progress in the field. This contribution summarizes the twelve topical discussions held during the program and collects individual thoughts of speakers and panelists on the future of the field in light of these discussions.
Published as SciPost Phys. Comm. Rep. 11 (2025)
Reports on this Submission
Report #2 by Anonymous (Referee 2) on 2025-6-23 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2412.08696v2, delivered 2025-06-23, doi: 10.21468/SciPost.Report.11449
Report
Publish. See attached file
Recommendation
Publish (easily meets expectations and criteria for this Journal; among top 50%)
Report #1 by Anonymous (Referee 1) on 2025-5-22 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2412.08696v2, delivered 2025-05-22, doi: 10.21468/SciPost.Report.11243
Report
This manuscript is a “Community Report,” consisting of a collection of contributions based on the activities developed during the Nordita Program “Quantum Gravity: from gravitational effective field theories to ultraviolet complete approaches.” The program was structured over four weeks. During the first week, PhD-level lectures were delivered, covering various topics in quantum gravity. Lecture notes summarizing the content of that week are available on arXiv:2412.08690. The remaining three weeks were devoted to workshops focused on different aspects within the broad domain of quantum gravity, ranging from foundational and theoretical issues to phenomenology. In addition to research talks, a significant number of panel discussions were organized during those weeks.
A key feature of the Program was the gathering of different sub-communities within the broader “Quantum Gravity” field. In my view, having an extended period for dialogue among diverse lines of thought is essential in quantum gravity. Challenges faced by one particular approach may be more easily addressed by others, offering insights for progress or revealing common ground between seemingly antagonistic perspectives. Moreover, regardless of the chosen approach, the physical processes to be described are the same. The fundamental question of whether universal properties of quantum gravity emerge across different frameworks can only be answered through intense exchanges of ideas and mutual understanding among sub-communities. On a technical level, different approaches can also benefit from computational tools developed by others. Finally, identifying the precise points where distinct views truly disagree is crucial for progress, as such disagreements can lead to concrete, divergent predictions arising from these theories and thus opening up the chance to rule out some candidates.
The present manuscript compiles summaries of each panel held during the Program, highlighting the key ideas raised by the panelists and participants, along with concluding remarks for each session. This results in a representative overview of both convergences and disagreements among panelists, who largely come from different perspectives within the quantum gravity community. Additionally, all panels were recorded, and links to the recordings are provided alongside each summary, allowing interested readers to follow the full discussions (the lectures from the first week are also available online). The panels featured leading international scientists and experts in quantum gravity and neighboring fields such as quantum cosmology. As such, the material presented here is of exceptional value to the quantum gravity community, particularly for early-career researchers and future generations.
Besides the panel summaries, the manuscript also includes personal statements and reflections from each speaker and panelist, providing their main takeaways from the discussions, as well as their views on promising research directions and urgent problems that deserve attention. In this sense, given that the manuscript is a compilation of discussion summaries and individual perspectives, there is limited scope for questions or suggestions regarding the content itself. I would like to emphasize that the manuscript is very well written and its content is highly innovative, particularly due to the unique format of the Program it documents. It is not a typical proceedings volume summarizing individual talks, but rather a comprehensive collection of discussion summaries and personal views from the speakers and panelists.
I have a few minor suggestions for the authors to consider:
Page 5 (first paragraph): It is stated that “At the quantum level, Einstein’s theory lacks predictivity in the ultraviolet (UV) regime, i.e., at high energies, as it is plagued by UV divergences that cannot be absorbed in a finite number of free parameters.” — In a generic context, I would not object, but since there are several approaches trying precisely to make sense of Einstein’s theory non-perturbatively, the issue of predictivity (or lack of it) is unclear. Hence, I would suggest that the authors emphasize that such a statement is valid within perturbation theory.
Page 5 (end): The phrase “...direct detection of gravitational waves (GWs) [19] and the construction of BH shadows [20]...” — The word “construction” sounds strange to me in the context it was used.
Page 14 (“Landscapes and predictivity” paragraph): The sentence “One key example is QCD: the fundamental Lagrangian is simple, but the low-energy vacuum structure is very complicated.” — I did not understand how this compares (or what is the analogy) with the discussion regarding ST’s landscape. The non-triviality of the vacuum structure in this case is tied to the non-perturbative nature of QCD in the low-energy regime and to my knowledge, the origin of the “landscape problem” in ST is totally different. I would suggest some elaboration on what was meant by this analogy.
Page 19: There is a typo in the third line: “...of new physics, such us…”
I also noticed a few additional minor typos scattered throughout the text, but they are easily fixed and do not need to be listed individually.
In summary: I strongly recommend the publication of this manuscript. I believe the Nordita Program and the resulting material constitute outstanding contributions to the quantum gravity community and to the ongoing effort of building bridges across different approaches within the field.
A key feature of the Program was the gathering of different sub-communities within the broader “Quantum Gravity” field. In my view, having an extended period for dialogue among diverse lines of thought is essential in quantum gravity. Challenges faced by one particular approach may be more easily addressed by others, offering insights for progress or revealing common ground between seemingly antagonistic perspectives. Moreover, regardless of the chosen approach, the physical processes to be described are the same. The fundamental question of whether universal properties of quantum gravity emerge across different frameworks can only be answered through intense exchanges of ideas and mutual understanding among sub-communities. On a technical level, different approaches can also benefit from computational tools developed by others. Finally, identifying the precise points where distinct views truly disagree is crucial for progress, as such disagreements can lead to concrete, divergent predictions arising from these theories and thus opening up the chance to rule out some candidates.
The present manuscript compiles summaries of each panel held during the Program, highlighting the key ideas raised by the panelists and participants, along with concluding remarks for each session. This results in a representative overview of both convergences and disagreements among panelists, who largely come from different perspectives within the quantum gravity community. Additionally, all panels were recorded, and links to the recordings are provided alongside each summary, allowing interested readers to follow the full discussions (the lectures from the first week are also available online). The panels featured leading international scientists and experts in quantum gravity and neighboring fields such as quantum cosmology. As such, the material presented here is of exceptional value to the quantum gravity community, particularly for early-career researchers and future generations.
Besides the panel summaries, the manuscript also includes personal statements and reflections from each speaker and panelist, providing their main takeaways from the discussions, as well as their views on promising research directions and urgent problems that deserve attention. In this sense, given that the manuscript is a compilation of discussion summaries and individual perspectives, there is limited scope for questions or suggestions regarding the content itself. I would like to emphasize that the manuscript is very well written and its content is highly innovative, particularly due to the unique format of the Program it documents. It is not a typical proceedings volume summarizing individual talks, but rather a comprehensive collection of discussion summaries and personal views from the speakers and panelists.
I have a few minor suggestions for the authors to consider:
Page 5 (first paragraph): It is stated that “At the quantum level, Einstein’s theory lacks predictivity in the ultraviolet (UV) regime, i.e., at high energies, as it is plagued by UV divergences that cannot be absorbed in a finite number of free parameters.” — In a generic context, I would not object, but since there are several approaches trying precisely to make sense of Einstein’s theory non-perturbatively, the issue of predictivity (or lack of it) is unclear. Hence, I would suggest that the authors emphasize that such a statement is valid within perturbation theory.
Page 5 (end): The phrase “...direct detection of gravitational waves (GWs) [19] and the construction of BH shadows [20]...” — The word “construction” sounds strange to me in the context it was used.
Page 14 (“Landscapes and predictivity” paragraph): The sentence “One key example is QCD: the fundamental Lagrangian is simple, but the low-energy vacuum structure is very complicated.” — I did not understand how this compares (or what is the analogy) with the discussion regarding ST’s landscape. The non-triviality of the vacuum structure in this case is tied to the non-perturbative nature of QCD in the low-energy regime and to my knowledge, the origin of the “landscape problem” in ST is totally different. I would suggest some elaboration on what was meant by this analogy.
Page 19: There is a typo in the third line: “...of new physics, such us…”
I also noticed a few additional minor typos scattered throughout the text, but they are easily fixed and do not need to be listed individually.
In summary: I strongly recommend the publication of this manuscript. I believe the Nordita Program and the resulting material constitute outstanding contributions to the quantum gravity community and to the ongoing effort of building bridges across different approaches within the field.
Recommendation
Publish (meets expectations and criteria for this Journal)