Search results from PIRSA
Format results
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Talk
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Opening Remarks
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Marcela Carena Perimeter Institute for Theoretical Physics
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Kendrick Smith Perimeter Institute for Theoretical Physics
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Cosmology: the last 25 years
Matias Zaldarriaga -
Measuring H0 and dark energy with DESI
Will Percival University of Waterloo
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Observable B modes from Cosmological Phase Transitions
Gordon Krnjaic -
Neutron Star Mergers: Probes of Extreme Matter
Pablo Bosch Gomez -
Can LIGO Detect Daylight Savings Time?
Reed Essick
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Talk
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Opening Remarks
Selim Hotinli Perimeter Institute for Theoretical Physics
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Baryon feedback: How extreme is too extreme?
Alexandra Amon Princeton University
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Cosmological feedback from a halo assembly perspective
Hiranya Peiris University of Cambridge
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Talk
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Opening Remarks
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Marcela Carena Perimeter Institute for Theoretical Physics
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Emily Petroff Perimeter Institute for Theoretical Physics
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Chris Waddell Perimeter Institute for Theoretical Physics
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Chaos and the Emergence of the Cosmological Horizon
David Kolchmeyer Massachusetts Institute of Technology
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Operator Algebras and Third Quantization
Nima Lashkari Purdue University West Lafayette
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Swing Surfaces in AdS/CFT
Sabrina Pasterski Perimeter Institute for Theoretical Physics
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An Emergent Area Operator in 2d CFT
Ronak Soni Chennai Mathematical Institute
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Gravity As An Oracle (Vision Talk)
Raphael Bousso University of California, Berkeley
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Vacuogenesis (Vision Talk)
Ted Jacobson University of Maryland, College Park
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Talk
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Talk
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Opening Remarks
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Marcela Carena Perimeter Institute for Theoretical Physics
- Laurent Freidel
PIRSA:25060029 -
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Gravitational collapse, shock waves and white holes
Viqar Husain University of New Brunswick
PIRSA:25060035 -
Building and (hints of) seeing gravitational statistical mechanics
Seth Major Hamilton College
PIRSA:25060036
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Talk
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Causal Inference Meets Quantum Physics
Robert Spekkens Perimeter Institute for Theoretical Physics
PIRSA:25040086 -
Creativity by Compositionality in Generative Diffusion Models
Alessandro Favero École Polytechnique Fédérale de Lausanne
PIRSA:25040088 -
Towards a “Theoretical Minimum” for Physicists in AI
Yonatan Kahn Princeton University
PIRSA:25040089 -
Solvable models of scaling and emergence in deep learning
Cengiz Pehlevan Harvard University
PIRSA:25040091 -
Architectural bias in a transport-based generative model : an asymptotic perspective
Hugo Cui Harvard University
PIRSA:25040092 -
Statistical physics of learning with two-layer neural networks
Bruno Loureiro École Normale Supérieure - PSL
PIRSA:25040093 -
Renormalization Group Flows: from Optimal Transport to Diffusion Models
Jordan Cotler Harvard University
PIRSA:25040095
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Beautiful Papers, PHYS 773, September 12 - December 1, 2025
*Scroll down to Registration and Enrollment to participate.* **Structure:** We will discuss 8 papers which had huge impact in physics. One week Instructor Pedro Vieira will discuss a paper; students should read it beforehand. One week later students discuss recent papers referring to that paper (20 min each student, ~ 3 presentations; at the end of the class Pedro will grade the presentations based on “Physics”, “Presentation”, “Question handling”; and give comments). By the end of the course, students will have explored a vast set of topics in theoretical physics — spotting potential gaps to be fixed — sharpened their presentation skills through steady practice, and sparked cross-disciplinary conversations through our shared physics language. *Familiarity with Quantum Field Theory and General Relativity is assumed.* **The papers:** Sept 12 & 19: On the Quantum Correction for Thermodynamic Equilibrium, Wigner, 1932 Topic: Quantum Mechanics Sept 22 & 29: Existence theorem for certain systems of nonlinear PDEs, Foures-Bruhat, 1952 Topic: General relativity Oct 3 & 10: The Renormalization Group and the Epsilon Expansion, Wilson and Kogut, 1973 Topic: Quantum Field Theory **Oct 10 (EXTRA)** & 17: More about the Massive Schwinger Model, Coleman, 1976 Topic: 2D Quantum Field Theory Oct 20 & 27: A sequence of approximated solutions to the S-K model for spin glasses, Parisi, 1980 Topic: Statistical Mechanics Oct 31 & Nov 7: Quantum Field Theory and the Jones Polynomial, Witten, 1988 Topic: Topological Quantum Field Theory Nov 10 & 17: Exactly Solvable Field Theories of Closed Strings, Brezin, Kazakov, 1989 Topic: 2D Quantum Gravity Nov 21 & Nov 28: Unpaired Majorana fermions in quantum wires, Kitaev, 2000 Topic: Quantum Matter/Quantum Information **Schedule:** This is a Friday / Monday alternating week schedule from 915am-1045am. **Exceptions:** There will be an afternoon session at 130pm on Friday October 10 to avoid the Thanksgiving holiday. **Location & Building Access:** Alice Room, 3rd Floor, Perimeter Institute, 31 Caroline St N, Waterloo Participants who do not have an access card for Perimeter Institute must sign in at the security desk before each session. For information on parking or accessibility please contact academic@perimeterinstitute.ca. **Registration and Enrollment:** Please sign-up here: https://forms.office.com/r/nDQ6SDxSR4 -
Combinatorial QFT, CO 739-002, September 4 - December 2, 2025
Quantum field theory intertwines continuous and discrete structures. On the discrete side, combinatorics plays a central role in describing and understanding its expansions and models. This lecture series focuses on the combinatorial aspects of quantum field theory. In the first part, we explore analytic combinatorics techniques, inspired by QFT, for the enumeration of graphs. These methods turn out to be surprisingly powerful in addressing deep questions in algebraic geometry, topology, and statistical models on graphs. In the second part, we turn to discrete structures arising in perturbative expansions of QFT. We study these from a modern combinatorics viewpoint, using tools such as Lorentzian polynomials and generalized permutahedra to better understand the mathematical objects at the heart of quantum field theory. For updates visit: https://michaelborinsky.com/combqft.html This course is offered by the University of Waterloo's Department of Combinatorics & Optimization; UW students can enroll through Quest. Lectures will be held at Perimeter Institute, 31 Caroline St N, Waterloo. Students will need to sign in and out of Perimeter each day. Note room change on Sept 25 and Oct 2, and no classes week of October 13. -
Classical Physics (Core), PHYS 612, September 2 - October 7, 2025
This is a theoretical physics course that aims to review the basics of theoretical mechanics, special relativity, and classical field theory, with the emphasis on geometrical notions and relativistic formalism, thus setting the stage for the forthcoming courses in Quantum Mechanics, and Quantum Field Theory in particular, as well as in General Relativity and Quantum Gravity. Instructor: Aldo Riello Students who are not part of the PSI MSc program should review enrollment and course format information here: https://perimeterinstitute.ca/graduate-courses -
Charting the Future Symposium
Charting the Future Symposium: Big questions in particle physics, strong gravity, and cosmology over the next 25 years
Join us for a special symposium celebrating Perimeter’s 25th anniversary. This event offers a unique opportunity to unite Perimeter alumni and friends in the fields of cosmology, particle physics, and strong gravity with our extended community, reflect on a quarter-century of discovery, and look ahead to the challenges and opportunities that will shape the next 25 years of fundamental physics.
Over the past quarter-century, we have witnessed transformative advances across our fields. In particle physics, the discovery of the Higgs boson crowned decades of effort, while precision experiments continue to probe the Standard Model and search for new physics. In strong gravity, the direct detection of gravitational waves has opened a new observational window onto black holes, neutron stars, and the very fabric of spacetime. In cosmology, precision measurements of the cosmic microwave background and large-scale structure have revolutionized our understanding of the universe’s origins and evolution, even as dark matter and dark energy remain profound mysteries.
As we look to the future, a new generation of experiments, observations, and theoretical ideas promises to drive further revolutions. From uncovering physics beyond the Standard Model to probing the nature of spacetime and the earliest moments of the cosmos, the next 25 years are poised to be as transformative as the last.
This symposium will bring together leading researchers, young scientists, alumni, and friends to celebrate past achievements, and imagine the discoveries yet to come. We invite you to be part of this landmark event at Perimeter Institute, as we honor the spirit of curiosity, ambition, and collaboration that has defined our journey so far — and will carry us forward
Invited Speakers
- Haipeng An (Tsinghua University)
- Masha Baryakhtar (University of Washington)
- Brian Batell (University of Pittsburgh)
- Laura Bernard (Observatoire de Paris)
- Richard Bond (CITA)
- Pablo Bosch Gomez (Utrecht University)
- Latham Boyle (University of Edinburgh)
- Patrick Brady (University of Wisconsin-Milwaukee)
- Joe Bramante (Queen's University)
- Savas Dimopoulos (Perimeter Institute)
- Adrienne Erickcek (University of North Carolina at Chapel Hill)
- Stefania Gori (UC Santa Cruz)
- Chad Hanna (Pennsylvania State)
- Renée Hložek (University of Toronto)
- Yoni Kahn (University of Toronto)
- Vicky Kaspi (McGill University)
- Gordan Krnjaic (Fermilab)
- Ian Low (Northwestern University)
- Mathew Madhavacheril (University of Pennsylvania)
- David Morissey (TRIUMF)
- Moritz Münchmeyer (University of Wisconsin-Madison)
- Ue-Li Pen (CITA, Perimeter Institute)
- Will Percival (Perimeter Institute)
- Maxim Pospelov (University of Minnesota)
- Josef Pradler (Austrian Academy of Sciences)
- Daniel Siegel (University of Greifswald)
- Nils Siemonsen (Princeton University)
- Carlos Wagner (University of Chicago)
- Huan Yang (Tsinghua University)
- Matias Zaldarriaga (IAS)
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Organizing Committee
Asimina Arvanitaki
Luis Lehner
Sergey Sibiryakov
Kendrick Smith -
Cosmic Ecosystems
In the past three decades, one of the most transformative insights in cosmology has been the realisation that the formation and evolution processes of cosmic structures such as supermassive black-holes, galaxies and clusters are deeply interconnected with the vast cosmic web that underpins the Universe. These processes do not happen in isolation, but are part of a dynamic ecosystem where matter and energy flow across scales, driving the growth and transformation of cosmic environments. Understanding this complex system, in particular the circum-galactic medium (CGM), is not only key to deciphering how matter is cycled and redistributed through accretion via filaments and outflows from AGN and supernovae, but also crucial for unlocking the next generation of discoveries in areas such as dark matter, the behaviour of the cosmic web, the forces that shape cosmic evolution, and more.This conference seeks to bring together cosmologists and astrophysicists to foster collaborative exploration of these interconnected cosmic ecosystems. By focusing on how structures interact with their environments across cosmic scales, this conference aims to catalyse groundbreaking discoveries in both astronomy and physics, providing fresh insights into the forces that govern the Universe. Special attention will be given to the joint analysis of large-scale structure and weak gravitational lensing data from surveys such as DESI, Euclid, LSST and Roman with CMB data from the Simons Observatory and CMB-S4, as well as how these can be integrated with observations of JWST, and existing and upcoming observations of X-ray emission, UV/X-ray absorption toward quasars, 21-cm emission, and FRBs.The goal is to explore the complementarity of these data sets and how their alignment can provide new insights into the interconnected processes shaping cosmic environments, particularly through joint modelling and simulations of many phases of gas and feedback across different regimes. Attention will also be given to bridging the gap between how cosmologists and astronomers approach the CGM, either top-down large-scale and hot and virial phase, vs bottom-up, cooler phases, at smaller scales.Topics will include:· Cosmic mass budget, including a census of where the baryons are.· Effect of baryons on dark matter structures on small and large scales.· Cosmic evolution of large-scale structures.· Bridging the gap between different probes.
Please see the Conference Themes for a more complete list of example topics.The time has never been more right to unify these fields, as advances in observation, theory and simulations are poised to open new paths to revealing the cosmos’ most profound mysteries.
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Organizing Committee (LOC)
Selim Hotinli (Perimeter Institute)
Neal Dalal (Perimeter Institute)
Mike Hudson (University of Waterloo, Waterloo Centre for Astrophysics)
Matt Johnson (Perimeter Institute)
Katie Mack (Perimeter Institute)
Brian McNamara (University of Waterloo, Waterloo Centre for Astrophysics)
Arielle Phillips (University of Notre Dame / Simons Emmy Noether Fellow at Perimeter Institute)
Kendrick Smith (Perimeter Institute)
Scientific Organizing Committee (SOC)
Nick Battaglia (Cornell)
Hsiao-Wen Chen (University of Chicago)
Megan Donahue (Michigan State University)
Claude-André Faucher-Giguère (Northwestern)
Cameron Hummels (Caltech)
Selim Hotinli (Perimeter Institute)
Ian McCarthy (Liverpool John Moores University)
Daisuke Nagai (Yale)
Gwen Rudie (Carnegie Institution for Science)
Freeke van de Voort (Cardiff University)
Jessica Werk (University of Washington)
Confirmed Speakers
Alexandra Amon (Princeton)
Iryna Butsky (Stanford)
William Coulton (Cambridge University)
Sanskrti Das (Stanford)
Simone Ferraro (Berkeley Lab)
Nicholas J Frontiere (Argonne)
Vera Gluscevic (USC)*
Timothy Heckman (JHU)*
Boryana Hadzhiyska (UC Berkeley & Berkeley Lab)*
Stella Koch Ocker (California Institute of Technology)
Khee-Gan Lee (IPMU)*
Nir Mandelker (Hebrew University Jerusalem)
Chris Martin (Caltech)
Daisuke Nagai (Yale)
Andrew Newman (Carnegie Institution for Science)
Peng Oh (UC Santa Barbara)
Hiranya Peiris (University of Cambridge)
Andrew Pontzen (Durham University)
Emanuel Schaan (SLAC)
Joop Schaye (Leiden University)*
Chuck Steidel (California Institute of Technology)
Jonathan Stern (Tel Aviv University)
Mark Voit (Michigan State University)
Irina Zhuravleva (University of Chicago)
*Virtual presenters
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QIQG 2025
QIQG 2025: Quantum Information in Quantum Gravity
QIQG 2025: Quantum Information In Quantum Gravity will unite researchers working at the intersection of quantum information theory and quantum gravity, to exchange insights and showcase recent developments bridging these fields. As part of the celebrations of Perimeter’s 25th anniversary, we will also feature vision talks by world-leading experts exploring pivotal and emerging themes at the nexus of quantum information and quantum gravity. Our program will span topics such as:- Algebraic approaches to field theory and gravity
- Observers, quantum reference frames, and relational observables
- Quantum focussing and the Generalized Second Law
- SYK and its double-scaled limit
- The quantum information theoretic structure of spacetime
- Edge modes and entanglement entropy across subregions
- The role of complexity in field theory and gravity
- The black-hole information puzzle and related issues
- Quantum error-correcting codes in quantum field theory and quantum gravity
- Quantum cryptography and its implications for gravity
- Gravitational wormholes and their information-theoretic implications
- Chaos and thermalization in many-body systems and their realization in quantum gravity
- Holographic cosmology and de Sitter space
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Scientific Organizers
Luca Ciambelli (Perimeter Institute)
Rob Myers (Perimeter Institute)
Chris Waddell (Perimeter Institute)
Beni Yoshida (Perimeter Institute)
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Energy Operators in Particle Physics, QFT, and Gravity - June 6-13, 2025
Detector operators, of which the average null energy operator provides the most famous example, arise as direct theoretical models of asymptotic measurements in collider experiments. In QFT, detector operators are expressed in terms of "light-ray operators", whose correlation functions provide an interesting class of non-perturbatively well-defined observables. There has recently been renewed interest in detector operators coming from three distinct directions: In CFTs, there has been progress understanding the space of light-ray operators, their organization into Regge trajectories, and their appearance in Lorentzian operator product expansions. In perturbative QFT and gravity, borrowing techniques from the study of scattering amplitudes, there has been progress understanding multi-point correlation functions of detector operators, in particular, their function space and singularities. Finally, in particle physics, there have recently been direct measurements of correlation functions of detector operators in collider experiments, enabling measurements of their scaling behavior and the structure of multi-point correlators of light-ray operators in QCD. In this mini-course I will give an introduction to the theory of light-ray/ detector operators, their correlators, and their applications in particle phenomenology, and provide an overview of the recent progress in the directions mentioned above. Throughout, I will attempt to highlight the different perspectives and motivations for studying these operators, coming from the CFT, amplitudes and phenomenological communities. I will conclude with a discussion of open problems in both theory and phenomenological applications, as well as highlighting areas where theoretical developments could have an impact on real world applications at colliders. Join live sessions via Zoom link: https://pitp.zoom.us/j/96935592330?pwd=NNtf7839TThLFEWIzdH7fYxNYksyYr.1 View all past talks on PIRSA: https://pirsa.org/c25035 -
Lee's Fest: Quantum Gravity and the Nature of Time
What is time? Is it fundamental or emergent? This question lies at the foundation of contemporary physics and provides a key to unlocking some of its most challenging open problems, from quantum gravity to cosmology. The quest to understand time extends beyond the realm of physics, providing a privileged standpoint to address questions in diverse fields such as philosophy, mathematics, and computer science.
In this conference, we explore the nature of time from many different perspectives. This is the occasion to honor Perimeter’s “Master of Time,” Lee Smolin, and to celebrate his seminal scientific contributions. Lee Smolin is a founding faculty member of Perimeter Institute and a primary inspiration behind its spirit and design. This is an opportunity to journey back in time to the origins of some of the groundbreaking initiatives that Lee helped develop, and to look forward to future developments inspired by his achievements. The conference focuses on time but also on the foundations of quantum mechanics and the quest for quantum gravity, particularly Loop Quantum Gravity, of which Lee Smolin is a co-creator. In the spirit of Lee Smolin, the conference celebrates the interdisciplinary nature of the journey toward quantum gravity, with contributions from physics, mathematics, computer science, and philosophy.
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Scientific Organizers
Laurent Freidel (Perimeter Institute)
Maïté Dupuis (Perimeter Institute)
Dongxue Qu (Perimeter Institute)
Francesca Vidotto (Western University):: :: ::
Speakers
- Niayesh Afshordi (University of Waterloo)
- Stephon Alexander (Brown University)
- Giovanni Amelino-Camelia (University of Naples Federico II)
- Julian Barbour (Independent)
- Bianca Dittrich (Perimeter Institute)
- Fay Dowker (Imperial College)
- Avshalom Elitzur (Chapman University)
- Lucien Hardy (Perimeter Institute)
- Viqar Husain (University of New Brunswick)
- Jenann Ismael (Johns Hopkins University)
- Ted Jacobson (Maryland University)
- Jaron Lanier (Microsoft Research)
- Etera Livine (Lyon, Ecole Normale Superieure)
- João Magueijo (Imperial College London)
- Seth Major (Hamilton College)
- Carlo Rovelli (Aix-Marseille University)
- Simon Saunders (Oxford University)
- Simone Speziale (Aix-Marseille University)
- Francesca Vidotto (Western University)
- Steven Weinstein (University of Waterloo)
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Credit: Artwork by Kaća Bradonjić -
Computing Quantum Gravity Workshop
A key task for many quantum gravity approaches is the development of effective numerical tools, in order to be able to extract physical predictions. This does apply in particular to approaches focusing on the Lorentzian path integral / Lorentzian spacetimes. The main aim of the workshop is to learn and develop methods to deal with Lorentzian signature. This will be a hands-on workshop, where projects will be pursued in small groups.
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Theory + AI Workshop: Theoretical Physics for AI
This 5-day program will explore the intersection of AI and fundamental theoretical physics. The event will feature two components, a symposium and a workshop, centered around two complementary themes: AI for theoretical physics and theoretical physics for AI.
The program will begin on April 7 and 8 with a large symposium with speakers and panel discussions focusing on the promise of AI to accelerate progress in theoretical physics. These talks will address the possibilities and challenges associated with AI ‘doing science.’ The event will bring together physicists, engineers, AI researchers, and entrepreneurs to collect different perspectives on what the future of theoretical physics will look like, the engineering challenges we should expect along the way, what tools and collaborations will be needed to help get us there, and what exciting steps are already underway.
Registration for the symposium is available on the symposium website.
The symposium will be followed by a workshop on April 9, 10, 11 focusing on developing a theoretical framework for AI enabling the development of reliable, robust, and interpretable AI models for physics. Recent advances in theoretical foundations of AI, inspired by techniques from string theory, quantum field theory (QFT), and statistical physics, have uncovered parallels between AI systems and physical theories, utilizing methods like renormalization group (RG) flows, Feynman path integrals etc. to deepen understanding of deep neural networks (DNNs), generative AI (e.g., LLMs and diffusion models), and scaling laws. Key topics include physics-informed optimization and learning, the role of RG and QFT for DNNs and generative AI, and the application of physics to AI interpretability. Through interdisciplinary dialogue, the event aims to foster collaborations, advance the theoretical foundations of AI, and explore its potential in areas like theoretical physics and mathematics.Speakers:
- David Berman (Queen Mary University of London)
- Blake Bordelon (Harvard University)
- Jordan Cotler (Harvard University)
- Hugo Cui (Harvard University)
- Alessandro Favero (EPFL)
- Ro Jefferson (Utrecht University)
- Yonatan Kahn (University of Toronto)
- Dmitry Krotov (IBM)
- Bruno Loureiro (École Normale Supérieure in Paris)
- Luisa Lucie-Smith (The University of Hamburg)
- Cengiz Pehlevan (Harvard University)
- Rob Spekkens (Perimeter Institute)
Scientific Organizers:
- Anindita Maiti (Perimeter Institute)
- Matt Johnson (Perimeter Institute)
- Sabrina Pasterski (Perimeter Institute)
Advisory Committee:
- Achim Kempf (University of Waterloo)
- Cengiz Pehlevan (Harvard University)
- Hiranya Peiris (University of Cambridge)
- Roger Melko (University of Waterloo)
