Quantum mechanics redefines information and its fundamental properties. Researchers at Perimeter Institute work to understand the properties of quantum information and study which information processing tasks are feasible, and which are infeasible or impossible. This includes research in quantum cryptography, which studies the tradeoff between information extraction and disturbance, and its applications. It also includes research in quantum error correction, which involves the study of methods for protecting information against decoherence. Another important side of the field is studying the application of quantum information techniques and insights to other areas of physics, including quantum foundations and condensed matter.
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Superselection Rules and Quantum Protocols
Dominic Mayers University of Sherbrooke

Quantum Gravity 2020
22 talksCollection Number C20031Talk

Reflections on quantum gravity in 2020
Ted Jacobson University of Maryland, College Park

Random tensors, melonic theories and quantum gravity
Sylvain Carrozza University of Burgundy

Dark Matter meets Quantum Gravity
Manuel Reichert University of Southern Denmark


Virasoro hair and entropy for axisymmetric Killing horizons
Linqing Chen Université Libre de Bruxelles

Black hole information, spacetime wormholes, and baby universes
Henry Maxfield University of California, Santa Barbara

Soft modes in quantum gravity
Monica Pate Harvard University

Free Energy from Replica Wormholes
Netta Engelhardt Massachusetts Institute of Technology (MIT)


Indefinite Causal Structure
26 talksCollection Number C19049Talk


TBA
Fabio Costa University of Queensland

Causality in Qbism
Jacques Pienaar University of Massachusetts Boston


TBA
Linqing Chen Université Libre de Bruxelles

Indefinite causal order without postselection
Katja Ried TNG Technology Consulting

TBA
Robert Mann University of Waterloo

Time reference frames and gravitating quantum clocks
Esteban Castro Ruiz Université Libre de Bruxelles (ULB)


Symmetry, Phases of Matter, and Resources in Quantum Computing
16 talksCollection Number C19048Talk


How Wilson lines in AdS redundantly compute CFT correlation functions
Bartek Czech Tsinghua University




Nogo theorems for quantum resource purification
ZiWen Liu Perimeter Institute for Theoretical Physics

Stabilizer codes for prime power qudits
Daniel Gottesman Perimeter Institute for Theoretical Physics



Boundaries and Defects in Quantum Field Theory
21 talksCollection Number C19035Talk

Quantum Work of an Optical Lattice and Boundary Field Theory
Natan Andrei Rutgers University

Colliders and conformal interfaces
Marco Meineri L'Ecole Polytechnique Federale de Lausanne (EPFL)

Entanglement negativity in manybody systems, and holography
Shinsei Ryu University of Illinois at UrbanaChampaign (UIUC)

Shape dependence of superconformal defects
Lorenzo Bianchi Queen Mary  University of London (QMUL)

Entanglement, free energy and Ctheorem in DCFT
Tatsuma Nishioka University of Tokyo

BPS Wilson loop in AdS4/CFT3
Silvia Penati University of MilanoBicocca

Boundary correlators of Liouville and Toda theories on AdS2 and AdS/CFT
Arkady Tseytlin Imperial College London

Wilson loops and defect CFT
Simone Giombi Princeton University


Machine Learning for Quantum Design
30 talksCollection Number C19025Talk


Differentiable Programming Tensor Networks and Quantum Circuits
Lei Wang Chinese Academy of Sciences

RLdriven Quantum Computation
Pooya Ronagh Perimeter Institute for Theoretical Physics

Glassy and Correlated Phases of Optimal Quantum Control
Marin Bukov University of California System

Neural BeliefPropagation Decoders for Quantum ErrorCorrecting Codes
Yehua Liu University of Sherbrooke

Operational quantum tomography
Olivia Di Matteo TRIUMF (Canada's National Laboratory for Particle and Nuclear Physics)

Machine learning phase discovery in quantum gas microscope images
Ehsan Khatami San Jose State University

Machine Learning Physics: From Quantum Mechanics to Holographic Geometry
YiZhuang You University of California, San Diego


Foundations of Quantum Mechanics
17 talksCollection Number C18020Talk


Counterfactual communication protocols
Lev Vaidman Tel Aviv University


Models and Tests of Quantum Theory and Gravity
Adrian Kent University of Cambridge



Measures of Preparation Contextuality
Matthew Leifer Chapman University

Observables and (no) time in quantum gravity
Bianca Dittrich Perimeter Institute for Theoretical Physics


Talk

From 3D TQFTs to 4D models with defects
Bianca Dittrich Perimeter Institute for Theoretical Physics

Hopf algebras and parafermionic lattice models
Joost Slingerland National University of Ireland

Frobenius algebras, Hopf algebras and 3categories
David Reutter Universität Hamburg




Interacting Hopf monoids and Graphical Linear Algebra
Pawel Sobocinski University of Southampton

Introduction to CQM
Ross Duncan University of Oxford


Contextuality: Conceptual Issues, Operational Signatures, and Applications
23 talksCollection Number C17027Talk

How to go from the KS theorem to experimentally testable noncontextuality inequalities
Ravi Kunjwal Funds for Scientific Research  FNRS


Contextuality and Temporal Correlations in Quantum Mechanics
Otfried Guhne University of Siegen


Contextuality as a resource for quantum computation: the trouble with qubits
Juan BermejoVega Freie Universität Berlin

Contextuality and noncontextuality in (qudit) quantum computation
Dan Browne University College London (UCL)  Department of Physics & Astronomy


Contextuality and quantum simulation
Stephen Bartlett University of Sydney


It from Qubit Summer School
62 talksCollection Number C16003Talk

Toy Holography
Daniel Harlow Massachusetts Institute of Technology (MIT)

Quantum Gravity and Quantum Chaos
Stephen Shenker Stanford University

Why physicists should care about the complexity zoo
Adam Buland Massachusetts Institute of Technology

Eigenstate Thermalization Hypothesis
Markus Müller Institute for Quantum Optics and Quantum Information (IQOQI)  Vienna

Modular hamiltonians in 2d CFT
John Cardy University of California System

Tensor Network Holography

Vijay Balasubramanian University of Pennsylvania

Xiaoliang Qi Stanford University

Brian Swingle University of Maryland, College Park


Black Hole Information Paradox  2
Daniel Harlow Massachusetts Institute of Technology (MIT)

Quantum NP and the Complexity of Ground States
Dorit Aharonov Hebrew University of Jerusalem


Quantum Information in Quantum Gravity II
30 talksCollection Number C15041Talk

The Complexity and (Un)Computability of Quantum Phase Transitions
James Watson University of Maryland, College Park

Introduction to Quantinuum and TKET
Mark Jackson Paris Centre for Cosmological Physics (PCCP)

Quantum simulation of Z2 lattice gauge theory with dynamical matter
Fabian Grusdt LudwigMaximiliansUniversitiät München (LMU)

NLTS Hamiltonians from good quantum codes
Anurag Anshu Harvard University

Positivity, negativity, entanglement, and holography
Mukund Rangamani University of California System

3D Holography: from discretum to continuum
Bianca Dittrich Perimeter Institute for Theoretical Physics

Quantum Fisher metric in field theory and gravity
Nima Lashkari McGill University

Wormholes and Complexity
Adam Brown Stanford University


Quantum Information and Relativity Theory
Quantum mechanics, information theory, and relativity theory are the basic foundations of theoretical physics. The acquisition of information from a quantum system is the interface of classical and quantum physics. Special relativity imposes severe restrictions on the transfer of information between distant systems. Various applications will be presented. 
Superselection Rules and Quantum Protocols
Dominic Mayers University of Sherbrooke
Superselection rules are limitations on the physically realizable quantum operations that can be carried out by a local agent. For example, it is impossible to create or destroy an isolated particle that carries locally conserved charges, such as an electrically charged particle, a fermion, or (in a two dimensional medium) an anyon. Recently, Popescu has suggested that superselection rules might have interesting implications for the security of quantum cryptographic protocols. The intuitive idea behind this suggestion is that superselection rules could place inescapable limits on the cheating strategies available to the dishonest parties, thus enhancing security. Might, say, unconditionally secure bit commitment be possible in worlds (perhaps including the physical world that we inhabit) governed by suitable superselection rules? An affirmative answer could shake the foundations of cryptography. The purpose of this paper is to answer Popescu's intriguing question. Sadly, our conclusion is that superselection rules can never foil a cheater who has unlimited quantum computational power. 
Quantum Gravity 2020
22 talksCollection Number C20031 
Indefinite Causal Structure
26 talksCollection Number C19049There has been a surge of interest in indefinite causal structure the idea that cause and effect can no longer be sharply distinguished. Motivated both by experimentation with quantum switches and quantum gravity there can be situations in which there is no matterofthefact as to what the causal structure of spacetime is. This meeting will bring together workers in Quantum Foundations and Quantum Gravity in both theoretical experimental physics to discuss the state of the art of current research and set new directions for this emerging subdiscipline.

Symmetry, Phases of Matter, and Resources in Quantum Computing
16 talksCollection Number C19048Our conference covers three related subjects: quantum faulttolerance magic states and resource theories and quantum computational phases of matter. The linking elements between them are (a) on the phenomenological side the persistence of computational power under perturbations and (b) on the theory side symmetry. The latter is necessary for the working of all three. The subjects are close but not identical and we expect crossfertilization between them.Fault tolerance is an essential component of universal scalable quantum computing.However known practical methods of achieving fault tolerance are extremely resource intensive. Distillation of magic states is in the current paradigm of faulttolerance the costliest operational component by a large margin. It is therefore pertinent to improve the efficiency of such procedures study theoretical limits of efficiency and more generally to establish a resource theory of quantum state magic. During the workshop we will focus on a fundamental connection between faulttolerant protocols and symmetries.``Computational phases of matters are a surprising link between quantum computation and condensed matter physics. Namely in the presence of suitable symmetries the ground states of spin Hamiltonians have computational power within the scheme of measurementbased quantum computation and this power is uniform across physical phases. Several computationally universal phases have to date been discovered. This subject is distinct from the above but linked to them by the feature of persistence of computational power under deformations and deviations.

Boundaries and Defects in Quantum Field Theory
21 talksCollection Number C19035Boundaries 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 ctheorems 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.

Machine Learning for Quantum Design
30 talksCollection Number C19025Machine learning techniques are rapidly being adopted into the field of quantum manybody physics including condensed matter theory experiment and quantum information science. The steady increase in data being produced by highlycontrolled 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 manybody 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: Datadrive quantum state reconstruction Machine learning strategies for quantum error correction Neuralnetwork based wavefunctions Nearterm prospects for data from quantum devices Machine learning for quantum algorithm discovery Registration for this event is now closed

Foundations of Quantum Mechanics
17 talksCollection Number C18020The 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

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.

Contextuality: Conceptual Issues, Operational Signatures, and Applications
23 talksCollection Number C170272017 marks 50 years since the seminal 1967 article of Kochen and Specker proving that quantum theory fails to admit of a noncontextual model. Despite the fact that the KochenSpecker theorem is one of the seminal results concerning the foundations of quantum theory, there has never been a large conference dedicated to the subject. The 50year anniversary of the theorem seems an opportune time to remedy this oversight. Furthermore, in the last decade, there have been tremendous advances in the field. New life has been breathed into the subject as old conceptual issues have been reexamined from a new informationtheoretic perspective. Importantly, there has been great progress in making the notion of noncontextuality robust to noise and therefore experimentally testable. Finally, there is mounting evidence that the resource that powers many quantum advantages for information processing is contextuality. In particular, it has been shown to underlie the possibility of universal quantum computation. Many groups worldwide are actively engaged in advancing our knowledge on each of these fronts and in deepening our understanding of the distinction between quantum and classical theories through the lens of contextuality. Through this conference, we aim to bring together leading researchers in the field in order to develop a broader perspective on the issues, draw connections between different approaches, foster a more cohesive community, and set objectives for future research.


Quantum Information in Quantum Gravity II
30 talksCollection Number C15041Quantum Information in Quantum Gravity II