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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: session is cancelled for Sept 25; there is a room change for Oct 2 & Nov 11, and no classes week of October 13.

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 29 (New Date) & 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 [email protected].

Registration and Enrollment: Please sign-up here: https://forms.office.com/r/nDQ6SDxSR4

This series is a crash course introduction to a handful of advanced topics designed to tackle the general problem of how to engineer Positive Operator-Valued Measures (POVMs) using observable building blocks, the so-called Instrument Manifold Program. This program emerged from a recent fundamental breakthrough: how to realize the measurement of a spin’s direction, a.k.a. the spin-coherent-state POVM, a spherical set of outcomes analogous to the well known coherent-state POVM of the standard phase plane.

Mostly ignore the Introduction content of the Oct 27 lecture (up to 14:14). The content and direction of the course evolved such that different portions of the “Old Schedule” (at 0:27) were covered. The schedule on this page has been corrected and now accurately reflects the content of the lectures.

The “Supplements” on Oct 30 and Nov 06 are actually just Lectures.

Outline:
Oct 27: The Planimeter and the Weyl-Heisenberg Group of Kinematic Transformations
Oct 30: The Planimeter and the Weyl-Heisenberg Group of Canonical Transformations
Nov 03: No Class
Nov 06: Measuring Instruments, Indirect Quantum Measurement, and Positive Gaussian Kraus Operators
Nov 10: Gaussian Channels, Gaussian Random Unitaries, and Sequential Measurements
Nov 13: Wiener Increments and the Ito Rules
Nov 17: No Class
Nov 20: General Gaussian Kraus Operators, Lindblad Operators, and Diffusive Measurement
Nov 24: The Markov Property and The Central Limit Theorem
Nov 27: Instrumental Groups, von Neumann Measurement, and Diffusive Heterodyne
Dec 01: No Class
Dec 04: The Stratonovich Product, The Maurer-Cartan Stochastic Differential, and Indirect Homodyne
Dec 08: The Kraus-Operator Density and The Fokker-Planck-Kolmogorov Equation of a Diffusive Measurement
Dec 11: Simultaneous Diffusive Measurements of Non-Commuting Observables and the Instrument Manifold Program

Location & Building Access: Alice Room, 3rd Floor, Perimeter Institute, 31 Caroline St N, Waterloo (Exception - November 27 in Space Room, 4th Floor)

Registration: Please sign-up here: https://forms.office.com/r/dEA4EUq0CU

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 [email protected].

The aim of this course is to explore the main ideas of the statistical physics approach to critical phenomena. We will discuss phase transitions, using the ferromagnetic phase transition and the Ising model as our primary example. The renormalisation group approach will be an important part of this course.

Holomorphic-topological field theories and representation theory

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Conference Speakers

Mina Aganagic (University of California, Berkeley) Christopher Beem (University of Oxford) Tudor Dimofte (University of Edinburgh) Sergei Gukov (California institute of Technology) Hans Jockers (Johannes Gutenberg University Mainz) Ahsan Khan (Harvard University) Satoshi Nawata (Fudan University) Andrew Neitzke (Yale University) Tony Pantev (University of Pennsylvania) Harold Williams (University of Southern California) Brian Williams (Boston University)

 

Workshop Organizers
Davide Gaiotto
Wenjun Niu
Ben Webster

The aim is to have two types of talks concerning the history: those that present novel takes on well-studied historical topics and those that address more unconventional historical questions.  The second category aims to include talks on the history of a variety of subfields of quantum theory, such quantum information, quantum field theory, quantum optics, quantum logic, quantum chemistry, quantum gravity, quantum matter and quantum foundations..

Conference topics include:

• The prehistory of modern quantum theory 
• The historical development of modern quantum theory
• The discovery of Important concepts in quantum theory (the uncertainty principle, wave-particle duality, particle statistics, the no-cloning theorem, teleportation, etc.)
• The discovery of important no-go results (von Neumann’s no-go theorem, the 1935 Einstein-Podolsky-Rosen argument, Bell’s theorem, the Kochen-Specker theorem)
• The history of quantum information, quantum field theory, quantum optics, quantum logic, quantum chemistry, quantum gravity, and quantum matter
• The sociology of quantum physics

 

 

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Scientific Organizers:

• Robert Spekkens (Perimeter Institute)

• Wayne Myrvold (Western University)

• Doreen Fraser (University of Waterloo)

• Katherine Mack (Perimeter Institute)

• David Schmid (Perimeter Institute)

• Nick Ormrod (Perimeter Institute)

• Marina Maciel Ansanelli (Perimeter Institute)

• Yile Ying (Perimeter Institute)

 

Confirmed Speakers:

The annual Graduate Students’ Conference showcases the diverse research directions at Perimeter Institute, both organized and presented by the students. Our graduate students are invited to share their best work with their fellow PhD students, PSI students and other PI residents interested in hearing about physics research and discussing it in a lively atmosphere full of questions.

Year of Quantum Across Canada: From Fundamental Science to Applications

The Institute for Quantum Computing and the Perimeter Institute for Theoretical Physics will jointly host a meeting celebrating the 100 year anniversary of the discovery of quantum mechanics. 

The conference will celebrate and aim to strengthen the quantum information science community in Canada and beyond, by bringing together leading Canadian researchers as well as members of the broader quantum community. The program will highlight the fundamental advances being made in quantum information theory and how these advances lead to applications. 

 

Topics included in the program:

• Quantum metrology
• Quantum simulation and quantum advantage
• Quantum error-correction and fault tolerance
• Quantum complexity and algorithms
• Quantum communication and networks
• Quantum cryptography
• Quantum information in quantum matter and quantum gravity 
  
  

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Recorded Archive of Talks

Day 1 - Monday Oct 6 at IQC:
https://www.youtube.com/live/RXHSelMTHhU

Day 2 - Tuesday Oct 7 at IQC:
https://www.youtube.com/live/e5Qx7xuAMpQ

Day 3 and 4 - Wednesday Oct 8 and Thursday Oct 9 at Perimeter:
https://pirsa.org/c25033

 

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Speakers

Christian Bauer (Lawrence Berkeley National Laboratory)
Alexandre Blais (Université de Sherbrooke)
Sergey Bravyi (IBM Research - Thomas J. Watson Research Center)
Nikolas Breuckmann (University of Bristol)
Eric Chitambar (University of Illinois at Urbana-Champaign)
Soonwon Choi (MIT)
Zohreh Davoudi (University of Maryland)
Matthew Fisher (University of California, Santa Barbara)
Dakshita Khurana (University of Illinois Urbana-Champaign)
Aleksander Kubica (Yale University)
Hank Lamm (Fermilab)
Laura Mancinska (University of Copenhagen)
Antonio Mezzacapo (IBM)
John Preskill (Caltech)
Martin Savage (University of Washington)
Brian Swingle (Brandeis University)
Nathan Wiebe (University of Toronto)
Yu-Xiang Yang (The University of Hong Kong)

Co-Chairpersons

Marcela Carena (Perimeter Institute & University of Chicago & Fermilab)
Norbert Lütkenhaus (University of Waterloo, Institute for Quantum Computing)

Scientific Organizers and Convenors

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

In the last few years, a new perspective on probabilistic reasoning has been extensively developed with the help of tools from category theory. The idea is to shift focus from the measure-theoretic details to structural properties of information flow in the presence of uncertainty - independence, conditioning, nested uncertainty, etc. This shift allows one to reason without the need to specify a concrete model of uncertainty, be it discrete, continuous, Gaussian, possibilistic or one of many other instantiations. In this course I will present a high-level overview of the leading approach to categorical probability that is based on so-called Markov categories. We will focus on the diagrammatic language of Markov categories that can be understood without any knowledge of category theory. Using such diagrams, we can also express basic concepts that have been useful in proving a plethora of categorical versions of classical theorems - strong law of large numbers, de Finetti's theorem, d-separation criterion for Bayesian networks, ergodic decomposition theorem, zero/one laws and others.