COVID-19 information for PI Residents and Visitors
Over the past three decades, the idea of a path integral over geometries, describing gravity in various dimensions, has become increasingly central to many areas of theoretical physics, including string and M-theory, holography and quantum aspects of black holes and cosmology.
In each of these areas, the path integral is frequently invoked as a formal device although, as practitioners will admit, except in very special cases the basic formula remains undefined. Typically, classical saddle points are discussed, whether real or complex, but the required integrals are left unperformed.
This state of affairs is untenable because it leaves the theory on a shaky footing and hence does not permit a sound comparison of theoretical predictions with observations. The time has come to critically reassess the foundational ideas of the path integral for gravity, including its definition, evaluation and interpretation; to identify problems with
existing uses and claims based on it, and to seek improvements. The workshop will focus on the continuum theory and its semiclassical limit, with applications to cosmology, black holes and holography. In particular, the notion of a “Euclidean path integral” for a “wavefunction of the universe” will be addressed.
To this effect we intend to revisit discussion of “quantum geometrodynamics” from the path integral viewpoint and to pursue various applications. The developments in this direction that took place in the late 1970's and early 1980's were not incorporated in subsequent efforts, where the emphasis shifted to using a classical background with quantum fluctuations superimposed on it, a split which although useful in particular approximations can hardly be imagined to lie at the foundation of the theory. The revival of the discussion of the foundation of the path integral for gravity is made timely, we believe, by the introduction of new global methods such as Picard-Lefschetz theory.
The format of the workshop will be unusual. For the first three days, the mornings will begin with a longer, introductory lecture by each of the three organisers, setting out some of the foundational issues. This will be followed by shorter lectures by the participants, tackling the same foundational questions. The morning lectures, held in the Bob room, will be open to all Perimeter residents and visitors. They will be recorded and made available for viewing on PIRSA. Afternoons will be devoted to friendly and informal discussions, with participants invited to offer short contributions which follow up or develop points raised in the mornings, within a relaxed and highly conducive environment. Participation in these afternoon discussion sessions, as well as social events associated with the workshop, will be limited to registered workshop participants. The last two days of the workshop will be an opportunity for participants to continue discussions on topics which emerge as of greatest general interest, as well as to follow up in smaller groups on technical points or new ideas.
Registration for this workshop is now closed.
- Claudio Bunster, Centro de Estudios Cientificos
- Astrid Eichhorn, Heidelberg University
- Steffen Gielen, Perimeter Institute & Max Planck Institute
- Ruth Gregory, Durham University
- Jonathan Halliwell, Imperial College London
- James Hartle, University of California, Santa Barbara
- Thomas Hertog, University of Leuven
- Stefan Hollands, University of Leipzig
- Jean-Luc Lehners, Max Planck Institute
- Emil Mottola, Los Alamos National Lab
- Viatcheslav Mukhanov, Ludwig Maximilian University of Munich
- Roberto Percacci, Scuola Internazionale Superiore di Studi Avanzati
- Rafael Sorkin, Perimeter Institute
- Neil Turok, Perimeter Institute
- Itzhak Bars, University of Southern California
- Alice Bernamonti, Perimeter Institute
- Beatrice Bonga, Perimeter Institute
- Latham Boyle, Perimeter Institute
- Claudio Bunster, Centro de Estudios Cientificos
- Kevin Costello, Perimeter Institute
- Bianca Dittrich, Perimeter Institute
- Astrid Eichhorn, Heidelberg University
- Job Feldbrugge, Perimeter Institute
- Angelika Fertig, Perimeter Institute
- Laurent Freidel, Perimeter Institute
- Federico Galli, Perimeter Institute
- Steve Giddings, University of California, Santa Barbara
- Steffen Gielen, Perimeter Institute & Max Planck Institute
- Jaume Gomis, Perimeter Institute
- Ruth Gregory, Durham University
- Hal Haggard, Bard College
- Jonathan Halliwell, Imperial College London
- Lucien Hardy, Perimeter Institute
- James Hartle, University of California, Santa Barbara
- Thomas Hertog, University of Leuven
- Stefan Hollands, University of Leipzig
- Achim Kempf, Perimeter Institute
- Jean-Luc Lehners, Max Planck Institute
- Sebastian Mizera, Perimeter Institute
- Emil Mottola, Los Alamos National Lab
- Viatcheslav Mukhanov, Ludwig Maximilian University of Munich
- Roberto Percacci, Scuola Internazionale Superiore di Studi Avanzati
- Alfredo Perez, Centro de Estudios Cientificos
- Kasia Rejzner, University of York
- Mehdi Saravani, University of Nottingham
- Laura Sberna, Perimeter Institute
- Barak Shoshany, Perimeter Institute
- Vasudev Shyam, Perimeter Institute
- Lee Smolin, Perimeter Institute
- Rafael Sorkin, Perimeter Institute
- Nadine Stritzelberger, University of Waterloo
- Sumati Surya, Raman Research Institute
- Neil Turok, Perimeter Institute
- Alexander Zamolodchikov, Rutgers University
Monday, November 13, 2017
Time |
Event |
Location |
8:30 – 9:00am |
Registration |
Reception |
9:00 – 9:05am |
Welcome and Intro |
Bob Room |
9:05 – 10:30am |
Claudio Bunster, Centro de Estudios Cientificos |
Bob Room |
10:30 – 11:00am |
Coffee Break |
Bistro – 1st Floor |
11:00 - 11:35am | Viatcheslav Mukhanov, Ludwig Maximilian University of Munich TBA |
Bob Room |
11:35 – 12:10pm |
Bianca Dittrich, Perimeter Institute |
Bob Room |
12:10 – 12:45pm |
Emil Mottola, Los Alamos National Lab |
Bob Room |
12:45 – 2:00pm |
Lunch |
Bistro – 2nd Floor |
2:00 – 2:35pm |
Astrid Eichhorn, Heidelberg University |
Sky Room |
2:35 – 3:10pm |
Stefan Hollands, University of Leipzig |
Sky Room |
3:10 – 3:25pm |
Angelika Fertig, Perimeter Institute |
Sky Room |
3:25 - 3:40pm | Laura Sberna, Perimeter Institute Real time path integral for quantum tunnelling and pair creation II |
Sky Room |
3:40 – 3:55pm |
Alfredo Perez, Centro de Estudios Cientificos |
Sky Room |
3:55 – 4:30pm |
Coffee Break |
Bistro – 1st Floor |
4:30 – 5:30pm |
Discussion |
Sky Room |
5:30 – 6:00pm |
Ontario Tasting Adventure |
2nd Floor Bistro |
Tuesday, November 14, 2017
Time |
Event |
Location |
9:00 – 10:30am |
Neil Turok, Perimeter Institute |
Bob Room |
10:30 – 11:00am |
Coffee Break |
Bistro – 1st Floor |
11:00 – 11:35am |
Jean-Luc Lehners, Max Planck Institute |
Bob Room |
11:35 – 12:10pm |
James Hartle, University of California, Santa Barbara |
Bob Room |
12:10 – 12:45pm |
Thomas Hertog, University of Leuven |
Bob Room |
12:45 – 2:00pm |
Lunch |
Bistro – 2nd Floor |
2:00 – 2:35pm |
Steffen Gielen, Perimeter Institute & Max Planck Institute |
Sky Room |
2:35 – 3:10pm |
Hal Haggard, Bard College |
Sky Room |
3:10 – 3:25pm |
Job Feldbrugge, Perimeter Institute |
Sky Room |
3:25 – 4:25pm |
Discussion |
Sky Room |
4:25 – 5:00pm |
Coffee Break |
Bistro – 1st Floor |
5:00 – 9:00pm |
Star Gazing Excursion |
Meet at |
Wednesday, November 15, 2017
Time |
Event |
Location |
9:00 – 10:30am |
Rafael Sorkin, Perimeter Institute |
Bob Room |
10:30 – 11:00am |
Coffee Break |
Bistro – 1st Floor |
11:00 – 11:35am |
Jonathan Halliwell, Imperial College London |
Bob Room |
11:35 – 12:10pm |
Roberto Percacci, SISSA |
Bob Room |
12:10 – 12:45pm |
Lucien Hardy, Perimeter Institute |
Bob Room |
12:45 – 2:00pm |
Lunch |
Bistro – 2nd Floor |
2:00 – 3:00pm |
Colloquium |
Time Room |
3:10 – 3:45pm |
Ruth Gregory, Durham University |
Sky Room |
3:45 – 4:20pm |
Latham Boyle, Perimeter Institute |
Sky Room |
4:20 – 4:45pm |
Coffee Break |
Bistro – 1st Floor |
4:45 – 5:30pm |
Discussion |
Sky Room |
5:30 – 6:00pm |
Break |
|
6:00 – 9:00pm |
Banquet |
Bistro – 2nd Floor |
Thursday, November 16, 2017
Time |
Event |
Location |
10:00 – 10:45am |
Sumati Surya, Raman Research Institute |
Bob Room |
10:45 – 11:30am |
Coffee Break |
Bistro – 1st Floor |
11:30 – 12:45pm |
Alfredo Perez, Centro de Estudios Cientificos |
Bob Room |
12:45 – 2:00pm |
Lunch Note: Perimeter Orchestra will perform a 15 minute Beatles Medley at 1:00 pm in the Atrium. All are welcome |
Bistro – 2nd Floor |
2:00 – 2:15pm |
Lee Smolin, Perimeter Institute |
Sky Room |
2:15 – 3:00pm |
Chair: Bianca Dittrich, Perimeter Institute |
Sky Room |
3:00 – 3:45pm |
Chairs: Itzhak Bars, University of Southern California & |
Sky Room |
4:00 – 4:30pm |
Coffee Break |
Bistro – 1st Floor |
Friday, November 17, 2017
Time |
Event |
Location |
10:00 – 10:45am |
Chairs: Jonathan Halliwell, Imperial College London & |
Bob Room |
10:45 – 11:15am |
Coffee Break |
Bistro – 1st Floor |
11:15 – 12:00pm |
Chair: Astrid Eichhorn, Heidelberg University |
Bob Room |
12:00 – 12:30pm |
Chairs: Itzhak Bars, University of Southern California & |
Bob Room |
12:30 – 2:00pm |
Lunch |
Bistro – 2nd Floor |
2:00 – 4:00pm |
Chair: Rafael Sorkin, Perimeter Institute |
Sky Room |
Quantum incompleteness of inflation - part I
Surprises in the Path Integral for Gravity
The path integral for gravity and Fedosov quantization
An asymptotically safe point of view on the gravitational path integral
TBA
Semi-classical evaluation of the 3D gravity path integral and quasi-local holography
TBA
The significance of the proper time in the quantum mechanics of the gravitational field.
Welcome and Opening Remarks
Pages
Scientific Organizers:
- Claudio Bunster, Centro de Estudios Cientificos
- Rafael Sorkin, Perimeter Institute
- Neil Turok, Perimeter Institute