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QIQG 2025: Quantum Information in Quantum Gravity

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Scientific Organizers

Luca Ciambelli (Perimeter Institute)
Rob Myers (Perimeter Institute)
Chris Waddell (Perimeter Institute)
Beni Yoshida (Perimeter Institute)

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

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)

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Speakers

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Credit: Artwork by Kaća Bradonjić

 

This course in Cosmology provides a theoretical overview of the standard cosmological model. Key topics include the FRW metric and the homogeneous universe, the thermal history of the universe (with an emphasis on the hot Big Bang and equilibrium thermodynamics), inflation and scalar field dynamics, along with selected aspects of cosmological perturbation theory (time permitting). Instructor: Neal Dalal/Ghazal Geshnizjani Students who are not part of the PSI MSc program should review enrollment and course format information here: https://perimeterinstitute.ca/graduate-courses

Can the effectiveness of a medical treatment be determined without the expense of a randomized controlled trial? Can the impact of a new policy be disentangled from other factors that happen to vary at the same time? Questions such as these are the purview of the field of causal inference, a general-purpose science of cause and effect, applicable in domains ranging from epidemiology to economics. Researchers in this field seek in particular to find techniques for extracting causal conclusions from statistical data. Meanwhile, one of the most significant results in the foundations of quantum theory—Bell’s theorem—can also be understood as an attempt to disentangle correlation and causation. Recently, it has been recognized that Bell’s result is an early foray into the field of causal inference and that the insights derived from almost 60 years of research on his theorem can supplement and improve upon state-of-the-art causal inference techniques. In the other direction, the conceptual framework developed by causal inference researchers provides a fruitful new perspective on what could possibly count as a satisfactory causal explanation of the quantum correlations observed in Bell experiments. Efforts to elaborate upon these connections have led to an exciting flow of techniques and insights across the disciplinary divide. This course will explore what is happening at the intersection of these two fields. Instructor: Robert Spekkens/Bindiya Arora Students who are not part of the PSI MSc program should review enrollment and course format information here: https://perimeterinstitute.ca/graduate-courses

We will cover the basics of the gauge/gravity duality, including some of the following aspects: holographic fluids, applications to condensed matter systems, entanglement entropy, and recent advances in understanding the black hole information paradox. Instructor: David Kubiznak/Gang Xu Students who are not part of the PSI MSc program should review enrollment and course format information here: https://perimeterinstitute.ca/graduate-courses

This course will cover quantum phases of matter, with a focus on long-range entangled states, topological states, and quantum criticality. Instructor: Chong Wang/Subhayan Sahu Students who are not part of the PSI MSc program should review enrollment and course format information here: https://perimeterinstitute.ca/graduate-courses

The main goal of this course is to show in which ways General Relativity (GR) is similar, and especially in which ways it is different, from other gauge theories. The largest component of the course is dedicated to studying the specific symmetry structure of GR and how it intimately relates to its dynamics. To do so, we will introduce a host of concepts and techniques, broadly (and loosely) known under the name of “Covariant Phase Space Method”. This provides a different perspective on GR’s physics, a perspective in which phase space, rather than spacetime, is front and center. Along the way we will take a few detours: we will explore (parts of) the historical debate on whether gravity should be quantized at all, discuss how to think of time evolution when there is no absolute time, and go through Wald’s proposal of black hole entropy as a Noether charge. The intended outcome of the course is to provide a new perspective on GR which, hopefully, will inform you on why it is much harder to quantize than other theories – especially from a non-perturbative perspective. In this sense the course always keeps an eye on Quantum Gravity, even though there will be very little “quantum” in it. It is also a course that does not hinge on any specific approach to the quantization of gravity. Also, it is worth noting that the covariant phase space techniques are broadly used in the current literature on the black hole information paradox, soft symmetries, and holography, and is therefore a useful tool to learn if you are interested in any of these topics. 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

Interactive Theorem Provers (or Proof Assistants) are tools that verify and partially automate mathematical proofs. The process of encoding mathematics into these systems, known as formalisation, has gained significant interest due to its role in proof verification, generating verified code for computer algebra systems, and expanding digital mathematical libraries. It seems likely with the growth in sophistication of proof assistants, and progress of Generative AI technologies, interactive theorem provers will become a useful aide for research and teaching of mathematics.  Lean, a leading proof assistant, has grown in popularity thanks to its extensive mathlib library, which now covers most undergraduate mathematics and beyond. Notable milestones include the Liquid Tensor Experiment, which formalised a key result by Fields medalist Peter Scholze, and the rapid formalisation of the Polynomial Freiman-Ruzsa Conjecture led by Terry Tao.The goal of the workshop is to introduce mathematicia...

This is an annual discussion meeting of the Indian statistical physics community attended by scientists, postdoctoral fellows and graduate students, from across the country, working in the broad area of statistical physics.This meeting will be the 10th in the series. The following list of topics, that are covered in STATPHYS meetings of the International Union of Pure and Applied Physics, will be covered in this discussion meeting.General and mathematical aspectsRigorous results, exact solutions, probability theory, stochastic field theory, phase transitions and critical phenomena at equilibrium, information theory, optimization, etc.Out-of-equilibrium aspectsDriven systems, transport theory, relaxation and response dynamics, random processes, anomalous diffusion, fluctuation theorems, large deviations, out-of-equilibrium phase transitions, etc.Quantum fluids and condensed matterStrongly correlated electrons, cold atoms, graphene, mesoscopic quantum phenomena, fractional quantum Hall e...

The Turing lectures will be delivered by Prof. Gabriel Mindlin, University of Buenos Aires, Argentina, on the topic of The Physics of Birdsong. His recent work on the recovery of the songs of extinct species has received much attention and acclaim. He is an acknowledged expert in the field and is also the winner ofthe ICTP prize for his work on the subject and numerous other honours. The Turing lectures are expected to provide an overview of the neurophysical mechanisms that lead to the production of birdsong, the acoustic effects that the avian vocal organ generates, and the neural instructions needed to drive it. This topic draws on analysis and techniques from neuroscience, dynamics, and data science. Hence the discussion meeting  draws on speakers from all three topics. In addition to the tentative list of invited speakers below, we hope to invite about 15 researchers, consisting of young faculty, students and postdoctoral fellows with background in the above to participate in the ...

The Square Kilometre Array (SKA), set to begin operations in 2027, will be the world’s largest radio telescope marking one of the great scientific and engineering feats of the 21st century. The SKA will advance a wide range of research areas within astronomy, with a major focus on cosmology and radio continuum science at low and mid frequencies. Despite their different objectives, these two fields share a substantial overlap and thus stand to benefit from collaborative efforts in joint observation strategies, data calibration, and innovative analysis techniques.This two week long program aims to bring together national and international experts in radio cosmology and continuum science, fostering collaboration and training the next generation of researchers in these areas. The program will have two main components: a program and a school.The program (7-11 April 2025) will focus on the current state of observation, modelling, and inference tools for radio cosmology and continuum science....