Conference/School

Boundaries and defects play central roles in quantum field theory (QFT) both as means to make contact with nature and as tools to constrain and understand QFT itself. Boundaries in QFT can be used to model impurities and also the finite extent of sample sizes while interfaces allow for different phases of matter to interact in a controllable way. More formally these structures shed light on the structure of QFT by providing new examples of dualities and renormalization group flows.  Broadly speaking this meeting will focus on three areas: 1) formal and applied aspects of boundary and defect conformal field theory from anomalies and c-theorems to topological insulators 2) supersymmetry and duality from exact computations of new observables to the construction of new theories and 3) QFT in curved space and gravity from holographic computations of entanglement entropy to ideas in quantum information theory. Registration for this event is now open.

Quantum field theory (QFT) is a universal language for theoretical physics describing the Standard Model gravity early universe inflation and condensed matter phenomena such as phase transitions superconductors and quantum Hall fluids. A triumph of 20th century physics was to understand weakly coupled QFTs: theories whose interactions can be treated as small perturbations of otherwise freely moving particles. However weakly coupled QFTs represent a tiny island in an ocean of possibilities. They cannot capture many of the most interesting and important physical phenomena from the strong nuclear force to high temperature superconductivity.The critical challenge for the 21st century is to understand and solve strongly coupled QFTs. Meeting this challenge will require new physical insight new mathematics and new computational tools. Our collaboration combines deep knowledge of novel non-perturbative techniques with a concrete plan for attacking the problem of strong coupling. The starting point is the astonishing discovery that in numerous physical systems there is a unique quantum field theory consistent with general principles of symmetry and quantum mechanics. By analyzing the full implications of these general principles one can make sharp predictions for physical observables without resorting to approximations.This strategy is called the Bootstrap the topic of this three week program.

Machine learning techniques are rapidly being adopted into the field of quantum many-body physics including condensed matter theory experiment and quantum information science.  The steady increase in data being produced by highly-controlled quantum experiments brings the potential of machine learning algorithms to the forefront of scientific advancement.  Particularly exciting is the prospect of using machine learning for the discovery and design of quantum materials devices and computers.  In order to make progress the field must address a number of fundamental questions related to the challenges of studying many-body quantum mechanics using classical computing algorithms and hardware. The goal of this conference is to bring together experts in computational physics machine learning and quantum information to make headway on a number of related topics including: Data-drive quantum state reconstruction Machine learning strategies for quantum error correction Neural-network based wavefunctions Near-term prospects for data from quantum devices Machine learning for quantum algorithm discovery Registration for this event is now closed

On Thursday June 13 the Institute for Quantum Computing (IQC) and Perimeter Institute for Theoretical Physics (PI) will participate in the one-day Many-Body States and Dynamics Workshop II. The goal of the workshop is to describe ongoing efforts to experimentally realize quantum many-body states and dynamics and discuss interesting classes of states and dynamics that could be targeted. Experimentalists working on several platforms (such as photons atom and ion traps superconducting qubits exciton-polaritons or NMR) and theoreticians specialized in many-body theory (entanglement topological order gauge theories criticality chaos error correction holography) and numerical simulations (exact diagonalization Monte Carlo DMRG tensor networks) will meet for a morning workshop to identify and discuss common interests.

This third workshop of the Perimeter Institute series Emergence and Entanglement will center around four major frontiers in quantum matter research:  (i) topological matter including recently discovered phases in three dimensions and new routes toward experimental realization (ii) critical states of matter especially interacting CFTs in 2+1 dimensions and dualities (iii) state-of-the-art numerical approaches to tackle such many-body problems (e.g. DMRG MERA Monte Carlo) and (iv) quantum dynamics and thermalization.

This is an ongoing series of meetings held two or three times per year between researchers at Perimeter Institute and CITA. The goal of these meetings is to share new ideas and encourage interaction in PI and CITA's common fields of interest through a series of informal talks followed by discussions.

Higher algebra has become important throughout mathematics physics and mathematical physics and this conference will bring together leading experts in higher algebra and its mathematical physics applications. In physics the term algebra is used quite broadly any time you can take two operators or fields multiply them and write the answer in some standard form a physicist will be happy to call this an algebra. Higher algebra is characterized by the appearance of a hierarchy of multilinear operations (e.g. A_infty and L_infty algebras). These structures can be higher categorical in nature (e.g. derived categories cosmology theories) and can involve mixtures of operations and co-operations (Hopf algebras Frobenius algebras etc.). Some of these notions are purely algebraic (e.g. algebra objects in a category) while others are quite geometric (e.g. shifted symplectic structures). An early manifestation of higher algebra in high-energy physics was supersymmetry. Supersymmetry makes quantum field theory richer and thus more complicated but at the same time many aspects become more tractable and many problems become exactly solvable. Since then higher algebra has made numerous appearances in mathematical physics both high- and low-energy. A tell-tale sign of the occurrence of higher structures is when classification results involve cohomology. Group cohomology appeared in the classification of condensed matter systems by the results of Wen and collaborators. Altland and Zirnbauer s "ten-fold way" was explained by Kitaev using K-theory. And Kitaev's 16 types of vortex-fermion statistics were classified by spin modular categories. All these results were recently enhanced by the work of Freed and Hopkins based on cobordism theory. In high energy physics cohomology appears most visibly in the form of "anomalies". The Chern--Simons anomaly comes from the fourth cohomology class of a compact Lie group and the 5-brane anomaly is related to a certain cohomology class of the Spin group. The classification of conformal field theories involves the computation of all algebras objects in certain monoidal categories which is a type of non-abelian cohomology. Yet another important role for higher algebra in mathematical physics has been in the famous Langlands duality. Langlands duality began in number theory and then became geometry. It turned into physics when Kapustin and Witten realized geometric Langlands as an electromagnetic duality in cN=4 super Yang--Mills theory. Derived algebra higher categories shifted symplectic geometry cohomology and supersymmetry all appear in Langlands duality. The conference speakers and participants drawn from both sides of the Atlantic and connected by live video streams will explore these myriad aspects of higher algebra in mathematical physics.

The foundations of quantum mechanics have been revitalized in the past few decades by three developments:  (i) the influence of quantum computation and quantum information theory (ii) studies of the interplay between quantum theory and relativity particularly the analysis of indefinite causal structure and (iii) proposals to reconstruct quantum theory from basic axioms.  There have also been very interesting developments in understanding and classifying no=locality and contextuality using tools from sheaf theory and cohomology as well as operator algebras and category theory. The International Congress of Mathematical Physics is a natural forum for the discussion of these topics.  In the past there have been satellite workshops on topics like Operator algebras and quantum statistical mechanics which also address fundamental issues.  The modern study of quantum foundations is very much influenced and informed by mathematics:  sheaf theory and cohomology category theory information theory convex analysis in addition to the continuing interest in operator algebras and functional analysis. The aim of the workshop is to bring together researchers who have made substantial contribution to the recent developments.  The workshop will be held at Perimeter Institute over a five day period from July 30

The 2018 Tri-Institute Summer School on Elementary Particles (TRISEP) will be held July 9-20 2018 in Perimeter Institute for Theoretical Physics Waterloo ON, Canada. TRISEP is an international summer school organized jointly by the Perimeter Institute for Theoretical Physics, SNOLAB, and TRIUMF Canada s laboratory for particle and nuclear physics. TRISEP will feature lectures by leading experts in the field of particle physics in its broadest sense and is designed to be very interactive with ample time for questions, discussions and interaction with the speakers. The school is intended for graduate students of all levels who were already exposed to quantum field theory. For further information, please visit http:///.trisep.ca

Throughout the history of quantum field theory there has been a rich cross-pollination between high energy and condensed matter physics. From the theory of renormalization to the consequences of spontaneous symmetry breaking this interaction has been an incredibly fruitful one. In the last decade there has been a strong resurgence of interest in condensed matter systems in the high energy theoretical physics community. Taking advantage of developments in conformal field theories the conformal bootstrap gauge/gravity and other type of dualities as well as effective field theory techniques high energy theorists with all kinds of specialist backgrounds are thinking about the diverse behavior exhibited in low energy physical systems. Recent developments also employed quantum field theory ideas to improve our understanding of condensed and quantum matter systems as for example Femi liquids strange metals or the behavior of topological defects in ultra cold atom gases. For certain questions such approaches present relevant advantages with respect to more traditional techniques. Moreover in recent years the interplay between high energy and condensed matter physics found new fuel in the search for light dark matter. Indeed theoretical analyses have recently shifted the attention towards model for sub-GeV dark matter. The condensed matter community has played a crucial role in the design of possible new materials and detectors that could allow the observation of such particles. The aim of this workshop is to bring together like-minded high energy theorists with appropriate condensed matter theorists and experimentalists to tackle some of the most interesting problems in modern physics. The format has been designed to allow for plenty of time for open discussion and interaction between the participants. This will reinvigorate existing collaborations as well as create new fruitful ones.