Discussion Meeting on Canonical Quantum Gravity
25–29 August 2025
The topic of this discussion meeting is canonical quantum
gravity, which is an approach to quantum gravity based on
states and Hilbert spaces. There are many subtleties due to the
fact that time reparametrisations are a gauge symmetry, and
more broadly the nature of the diffeomorphism gauge
group. While there has been study on this topic since the 1960s
at least, recently there has been a new influx of interest from
the Indian string theory community.
This meeting was intended to serve three purposes:
- A review of the literature on canonical quantum gravity.
- Discussion of recent results.
- A discussion on what are the interesting and important open
questions.
Speakers
- Ghanashyam Date (CMI)
- Anurag Kaushal (ICTS)
- Alok Laddha (CMI)
- Kanhu Kishore Nanda (CMI)
- Onkar Parrikar (CMI)
- Naveen Prabhakar (ICTS)
- Suvrat Raju (ICTS)
- Sunil Kumar Sake (YITP, Kyoto University)
- Ronak M Soni (CMI)
- Sandip P. Trivedi (TIFR)
- Aron C. Wall (DAMTP, University of Cambridge) (online)
- Spenta Wadia (ICTS) (online)
Schedule
| 25/8/25 |
10 am- 1 pm |
Alok Laddha |
Review on canonical gravity 1 |
| 25/8/25 |
2 pm - 5 pm |
Suvrat Raju |
Perspective on WdW and Holography |
| 26/8/25 |
10 am- 1 pm |
Ghanshyam Date |
Review on canonical gravity 2 |
| 26/8/25 |
2 pm - 5 pm |
Anurag Kaushal and Naveen Prabhakar |
Gauge-fixing issues |
| 27/8/25 |
10 am- 1 pm |
Ronak M Soni |
Inner products, replica wormholes and one-dimensional Hilbert
spaces |
| 27/8/25 |
2 pm - 5 pm |
Naveen Prabhakar |
Observers and Measurements |
| 28/8/25 |
10 am- 1 pm |
Kanhu Kishore Nanda, Sunil Kumar Sake and Sandip Trivedi |
dS |
| 28/8/25 |
2-3:30 pm |
Ronak M Soni |
Virasoro TQFT |
| 28/8/25 |
3:30-5 pm |
Onkar Parrikar and Sunil Kumar Sake |
York time in JT gravity |
| 29/8/25 |
10 am- 11:30 am |
Aron Wall (online) |
Cauchy Slice Holography |
| 29/8/25 |
11:30 am - 1 pm |
Alok Laddha |
Discussion session |
| 29/8/25 |
2-5 pm |
Onkar Parrikar |
Discussion session |
Notes and References
Review on Canonical Gravity (Alok Laddha and Ghanshyam Date)
Ghanshyam Date's Notes
Perspective on WdW and Holography, and Observers (Suvrat Raju)
The main points covered are summarised
in arXiv:2404.00374.
Gauge-fixing Issues (Anurag Kaushal and Naveen Prabhakar)
This was partly based on the paper
arXiv:2501.03926.
Slides are also available
de Sitter Space (Kanhu Kishore Nanda, Sunil Kumar Sake and
Sandip P. Trivedi)
Slides
Inner Products (Ronak M Soni)
References:
- The first three parts of the talk were taken from various sources,
but arXiv:2509.05412
appeared soon after the meeting, which is a more in-depth and
pedagogical review of the same set of ideas.
-
The last part was taken from
arXiv:1703.01519,
arXiv:1911.11977
and
arXiv:2403.13047.
York Time in JT Gravity (Onkar Parrikar and Sunil Kumar Sake)
Slides
Cauchy Slice Holography (Aron Wall)
The talk was based on the papers
arXiv:2204.00591
and
arXiv:2407.16769.
Questions from the Discussion Section
Notes prepared by Siddharth Prabhu
|
