Spring Workshop on Quantum Gravity

This event has ended successfully.

The lectures were very enjoyable and fruitful for all participants, who learned a lot from Prof. Livine and had a very lively exchange of ideas. Thank you all very much! We look forward to seeing you again at the next event.
(Here is a photo of the days.)

3rd Intensive Lectures by Quantum Gravity Gatherings

26-28 July 2023 @ RIKEN, Wako, Japan

Being the most profound and challenging quest in the forefront of theoretical physics, Quantum Gravity seeks to understand the intricate interplay between the microscopic world of quantum mechanics and the macroscopic realm governed by general relativity. It is in this pursuit that the spinfoam approach has emerged as a captivating and promising avenue of exploration. At its core, this approach dissects spacetime into fundamental and indivisible building blocks called spinfoams, providing a basis for a discrete path integral formulation of quantum general relativity, rooted in the principles of topological field theory. By breaking down spacetime into these discrete entities, the spinfoam model provides a novel and mathematically elegant framework for studying the quantum nature of gravity and offers insights into the fundamental fabric of the universe.

In the third event of the intensive lecture series by the iTHEMS' Quantum Gravity Gatherings (QGG) study group, we will delve into the fascinating world of spinfoams, where spacetime and quantum mechanics intertwine. This time, our distinguished speaker, Prof. Etera Livine from the Ecole Normale Supérieure de Lyon, will give a three-day lecture on the theme of the Spinfoam Approach to Quantum Gravity. These lectures, organized in the style of QGG, have been thoughtfully designed to offer a pedagogical review of the subject while highlighting its essential and unique computational techniques. Through these lectures, attendees will gain a concrete understanding of the spinfoam approach and its potential application to their own research and studies.

This spinfoam approach also stands as a sophisticated mathematical framework that possesses the power to captivate the attention of physicists and mathematicians alike. Furthermore, it shares striking similarities with and addresses fundamental questions that are not only central to high-energy physics but also to the field of condensed matter physics, encompassing the shared exploration of topological aspects of their respective systems, the utilization of similar mathematical tools such as group field theory, and the study of emergent phenomena arising from collective dynamics. This cross-pollination of ideas and techniques between spinfoam quantum gravity and condensed matter physics has the potential to shed light on fundamental aspects of both fields and pave the way for new insights and discoveries. We sincerely hope that this event will bring together people of diverse disciplines and interests, create a vibrant environment for fruitful interactions and idea exchange, and nurture future interdisciplinary collaborations that transcend traditional boundaries.

The lectures will be presented in a blackboard-style format (in English, no online broadcasting), which aims to foster a more interactive experience, encouraging active participation and in-depth Q&A discussions. In addition, we will also arrange a special session where any interested participant will have the opportunity to give a short presentation on a topic of their choice. We believe that the casual and dynamic atmosphere of this event will help spark interactions among all the participants, especially graduate students and early-career researchers, and serve as a catalyst for collaborative learning where they can engage with one another and enthusiastically share ideas.


Registration Form

Intensive Talk

Prof. Etera Livine (ENS de Lyon)
(Prof. Livine's Webpage)

Spinfoam path integrals for Quantum Gravity
(a local picture of quantum geometry from topological field theory)

Abstract: At the crossroads of several approaches to quantum gravity, Spinfoams propose a discrete path integral for quantum general relativity built from topological field theory. With the spectrum of geometric operators directly read from the representation theory of the local symmetry group, they can be interpreted as a quantized version of Regge calculus and can be understood as implementing the dynamics of quantum states geometry in loop quantum gravity. I will explain the basics of the formalism, the motivations, the mathematical framework and the main tools. In three space-time dimensions, the spinfoam quantization of 3d gravity is given by the Turaev-Viro topological invariant, which is intimately related to the quantization of Chern-Simons theory. I will explain in particular how the spinfoam amplitudes solve the Wheeler-de Witt equation, implement the invariance under 3d diffeomorphisms (despite being formulated in a discretized space-time) and lead to a quasi-local version of holography. In four space-time dimensions, general relativity can be formulated as an almost-topological theory and I will explain how the existing spinfoam models introduce a sea of topological defects to re-create the gravitational degrees of freedom from a topological path integral. Finally, I will show how spinfoams are naturally defined in terms of group field theory, which are generalized tensor models, and the prospects that this opens. I will conclude with the main challenges and open lines of research of the field.


July 26
10:00 - 10:15 Registration and reception
10:15 - 11:45 Lecture 1
11:45 - 13:30 Lunch & coffee break
13:30 - 15:00 Lecture 2
15:00 - 16:00 Coffee break
16:00 - 17:00 Lecture 3
17:10 - 18:30 Short talk (short talk program)

July 27
10:00 - 11:45 Lecture 4
11:45 - 13:30 Lunch & coffee break
13:30 - 15:00 Lecture 5
15:00 - 16:00 Coffee break
16:00 - 17:00 Lecture 6
17:30 - 20:00 Banquet

July 28
10:00 - 11:45 Lecture 7
11:45 - 13:30 Lunch & coffee break
13:30 - 15:00 Lecture 8
15:00 - 16:00 Coffee break
16:00 - 17:00 Lecture 9 & Closing


435-437 Seminar Room, 4F of Main Research Building, RIKEN Wako Campus


Che-Yu Chen (iTHEMS)
Yuta Hamada (KEK)
Puttarak Jai-akson (iTHEMS)
Christy Kelly (iTHEMS)
Ryo Namba (iTHEMS)
Toshifumi Noumi (The University of Tokyo)
Naritaka Oshita (Kyoto Hakubi/iTHEMS)
Sotaro Sugishita (YITP)
Yuki Yokokura (iTHEMS)

Contact: Puttarak Jai-akson puttarak.jai-akson@riken.jp / Yuki Yokokura yuki.yokokura@riken.jp