Quantum gravity is concerned with unifying Einstein's general theory of relativity with quantum theory into a single theoretical framework. At Perimeter Institute, researchers are actively pursuing a number of approaches to this problem including loop quantum gravity, spin foam models, asymptotic safety, emergent gravity, string theory, and causal set theory. We are also particularly interested in experimental implications of these different proposals. As the aim is a unification of the laws of physics into a single theory, the search for quantum gravity overlaps with other areas such as cosmology, particle physics and the foundations of quantum theory.
Format results

15 talksCollection Number C19039
Talk


PSI 2019/2020  Relativity (Kubiznak)  Lecture 2
David Kubiznak Charles University

PSI 2019/2020  Relativity (Kubiznak)  Lecture 3
David Kubiznak Charles University

PSI 2019/2020  Relativity (Kubiznak)  Lecture 4
David Kubiznak Charles University

PSI 2019/2020  Relativity (Kubiznak)  Lecture 5
David Kubiznak Charles University

PSI 2019/2020  Relativity (Kubiznak)  Lecture 6
David Kubiznak Charles University

PSI 2019/2020  Relativity (Kubiznak)  Lecture 7
David Kubiznak Charles University

PSI 2019/2020  Relativity (Kubiznak)  Lecture 8
David Kubiznak Charles University


PSI 2019/2020  Classical Physics (Kubiznak)
8 talksCollection Number C19032Talk

PSI 2018/2019  Explorations in Quantum Gravity (Dupuis)
15 talksCollection Number C19014Talk

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 1

Bianca Dittrich Perimeter Institute for Theoretical Physics

Maïté Dupuis Perimeter Institute for Theoretical Physics


PSI 2018/2019  Explorations in Quantum Gravity  Lecture 2
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 3
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 4
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 5
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 6
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 7
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2018/2019  Explorations in Quantum Gravity  Lecture 8
Maïté Dupuis Perimeter Institute for Theoretical Physics


PSI 2017/2018  Quantum Gravity (Dupuis)
15 talksCollection Number C17052Talk

PSI 2017/2018  Quantum Gravity  Lecture 1
Beatrice Bonga Radboud Universiteit Nijmegen

PSI 2017/2018  Quantum Gravity  Lecture 2
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2017/2018  Quantum Gravity  Lecture 3
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2017/2018  Quantum Gravity  Lecture 4
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2017/2018  Quantum Gravity  Lecture 5
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2017/2018  Quantum Gravity  Lecture 6
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2017/2018  Quantum Gravity  Lecture 7
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2017/2018  Quantum Gravity  Lecture 8
Maïté Dupuis Perimeter Institute for Theoretical Physics


The Path Integral for Gravity
18 talksCollection Number C17057Talk

Welcome and Opening Remarks
Neil Turok University of Edinburgh

The significance of the proper time in the quantum mechanics of the gravitational field.
Claudio Bunster Centro de Estudios Científicos (CECs)

TBA
Viatcheslav Mukhanov LudwigMaximiliansUniversitiät München (LMU)

Semiclassical evaluation of the 3D gravity path integral and quasilocal holography
Bianca Dittrich Perimeter Institute for Theoretical Physics


An asymptotically safe point of view on the gravitational path integral
Astrid Eichhorn University of Southern Denmark

The path integral for gravity and Fedosov quantization
Stefan Hollands Universität Leipzig

Surprises in the Path Integral for Gravity
Neil Turok University of Edinburgh


Quantum Black Holes in the Sky?
34 talksCollection Number C17055Talk

Quantifying the evidence for black holes with GW and EM probes
Paolo Pani Instituto Superior Tecnico  Departamento de Física

Echoes from the Abyss: Tentative Evidence for PlanckScale Structure at Black Hole Horizons
Jahed Abedi University of Stavanger (UiS)

Improvements on the methods for searching echoes
Julian Westerweck Albert Einstein Institute

A modelindependent search for gravitationalwave echoes
Archisman Ghosh Institucio Catalana de Recerca I Estudis Avancats (ICREA)  Universitat de Barcelona

An alternative significance estimation for the evidence for echoes
Alex Nielsen Albert Einstein Institute


Inspiral Tests of Strongfield Gravity and Ringdown Tests of Quantum Black Holes
Kent Yagi University of Virginia

A Recipe for Echoes
Aaron Zimmerman The University of Texas at Austin


Lights, Sounds, Action in Strong Field Gravity.
Collection Number C17062 
Talk

Semisimple Hopf algebras and fusion categories
Cesar Galindo Universidad de los Andes

The Hopf C*algebraic quantum double models  symmetries beyond group theory
Andreas Bauer Freie Universität Berlin

Modular categories and the Witt group
Michael Mueger Radboud Universiteit Nijmegen

Topological Quantum Computation
Eric Rowell Texas A&M University

Gapped phases of matter vs. Topological field theories
Davide Gaiotto Perimeter Institute for Theoretical Physics

An Introduction to Hopf Algebra Gauge Theory
Derek Wise FriedrichAlexanderUniversität ErlangenNürnberg

Kitaev lattice models as a Hopf algebra gauge theory
Catherine Meusburger University of ErlangenNuremberg

Topological defects and highercategorical structures
Jurgen Fuchs Karlstad University


Making Quantum Gravity Computable
31 talksCollection Number C17023Talk

Welcome and Opening Remarks
Bianca Dittrich Perimeter Institute for Theoretical Physics

Introduction to Monte Carlo methods  1
Gerard Barkema Utrecht University

Introduction to Monte Carlo methods  2
Gerard Barkema Utrecht University

Introduction to Tensor Network methods  1
Guifre Vidal Alphabet (United States)

Introduction to Tensor Network methods  2
Guifre Vidal Alphabet (United States)

Tutorial: Introduction to Monte Carlo Methods

Gerard Barkema Utrecht University

Nilas Klitgaard Radboud Universiteit Nijmegen


Tutorial: Introduction to Tensor Network methods

Guifre Vidal Alphabet (United States)

Clement Delcamp Ghent University


Scientific Computing and Computational Science
Erik Schnetter Perimeter Institute for Theoretical Physics


Shape Dynamics Workshop
16 talksCollection Number C17015Talk

Shape Dynamics: Perspectives and Problems
Julian Barbour University of Oxford

The quantum equation of state of the universe produces a small cosmological constant
Tim Koslowski Universidad Nacional Autónoma De Mexico (UNAM)

Inflationary and preinflationary dynamics with the Starobinsky potential
Beatrice Bonga Radboud Universiteit Nijmegen

Relationalism and the speed of light: Are we in a relationship?
Yuri Bonder Universidad Nacional Autónoma De Mexico (UNAM)

Compact spherically symmetric solutions and gravitational collapse in SD
Flavio Mercati University of Naples Federico II

Selfgravitating fluid solutions of Shape Dynamics
Daniel Guariento Conestoga College

A WeylType Theorem in Geometrized Newtonian Gravity, and How It May Bear on Shape Dynamics
Erik Curiel LudwigMaximiliansUniversitiät München (LMU)



PSI 2016/2017  Explorations in Quantum Gravity (Dupuis)
15 talksCollection Number C17010Talk

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 1
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 2
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 3
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 4
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 5
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 6
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 7
Maïté Dupuis Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Quantum Gravity  Lecture 8
Maïté Dupuis Perimeter Institute for Theoretical Physics


Infrared Problems in QED and Quantum Gravity
Collection Number C16048

PSI 2019/2020  Relativity (Kubiznak)
15 talksCollection Number C19039PSI 2019/2020  Relativity (Kubiznak) 
PSI 2019/2020  Classical Physics (Kubiznak)
8 talksCollection Number C19032PSI 2019/2020  Classical Physics (Kubiznak) 
PSI 2018/2019  Explorations in Quantum Gravity (Dupuis)
15 talksCollection Number C19014PSI 2018/2019  Explorations in Quantum Gravity (Dupuis) 
PSI 2017/2018  Quantum Gravity (Dupuis)
15 talksCollection Number C17052PSI 2017/2018  Quantum Gravity (Dupuis) 
The Path Integral for Gravity
18 talksCollection Number C17057Over 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 Mtheory, 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 PicardLefschetz 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.

Quantum Black Holes in the Sky?
34 talksCollection Number C17055The past decade has witnessed significant breakthroughs in understanding the quantum nature of black holes, with insights coming from quantum information theory, numerical relativity, and string theory. At the same time, astrophysical and gravitational wave observations can now provide an unprecedented window into the phenomenology of black hole horizons. This workshop seeks to bring together leading experts in these fields to explore new theoretical and observational opportunities and synergies that could improve our physical understanding of quantum black holes.

Lights, Sounds, Action in Strong Field Gravity.
Collection Number C17062With LIGO/VIRGO in operation and detecting gravitational waves, the era of gravitational wave astronomy is upon us. In anticipation of further observations, this workshop will discuss the physics, astrophysics, and observational prospectsas well as challengesin gravitational wave sources including black holes, neutron stars, and other fascinating objects, in both the near and long term.

Hopf Algebras in Kitaev's Quantum Double Models: Mathematical Connections from Gauge Theory to Topological Quantum Computing and Categorical Quantum Mechanics
18 talksCollection Number C17029The Kitaev quantum double models are a family of topologically ordered spin models originally proposed to exploit the novel condensed matter phenomenology of topological phases for faulttolerant quantum computation. Their physics is inherited from topological quantum field theories, while their underlying mathematical structure is based on a class of Hopf algebras. This structure is also seen across diverse fields of physics, and so allows connections to be made between the Kitaev models and topics as varied as quantum gauge theory and modified strong complementarity. This workshop will explore this shared mathematical structure and in so doing develop the connections between the fields of mathematical physics, quantum gravity, quantum information, condensed matter and quantum foundations.

Making Quantum Gravity Computable
31 talksCollection Number C17023Making Quantum Gravity Computable


PSI 2016/2017  Explorations in Quantum Gravity (Dupuis)
15 talksCollection Number C17010PSI 2016/2017  Explorations in Quantum Gravity (Dupuis) 
Infrared Problems in QED and Quantum Gravity
Collection Number C16048Infrared Problems in QED and Quantum Gravity