Quantum foundations concerns the conceptual and mathematical underpinnings of quantum theory. In particular, we search for novel quantum effects, consider how to interpret the formalism, ask where the formalism comes from, and how we might modify it. Research at Perimeter Institute is particularly concerned with reconstructing quantum theory from more natural postulates and reformulating the theory in ways that elucidate its conceptual structure. Research in the foundations of quantum theory naturally interfaces with research in quantum information and quantum gravity.
Displaying 13 - 24 of 1111
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Semisimple Hopf algebras and fusion categories
Cesar Galindo Universidad de los Andes
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The Hopf C*-algebraic quantum double models - symmetries beyond group theory
Andreas Bauer Freie Universität Berlin
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Modular categories and the Witt group
Michael Mueger Radboud Universiteit Nijmegen
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Topological Quantum Computation
Eric Rowell Texas A&M University
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Gapped phases of matter vs. Topological field theories
Davide Gaiotto Perimeter Institute for Theoretical Physics
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An Introduction to Hopf Algebra Gauge Theory
Derek Wise University of Erlangen-Nuremberg
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Kitaev lattice models as a Hopf algebra gauge theory
Catherine Meusburger University of Erlangen-Nuremberg
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Topological defects and higher-categorical structures
Jurgen Fuchs Karlstad University
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Contextuality: Conceptual Issues, Operational Signatures, and Applications
23 talks-Collection Number C17027Talk
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Welcome and Opening Remarks
Robert Spekkens Perimeter Institute for Theoretical Physics
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Quantum Mechanics in a New Key
Simon Kochen Princeton University
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What do we learn about quantum theory from Kochen-Specker quantum contextuality?
Adan Cabello Universidad de Sevilla
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Noncontextuality: how we should define it, why it is natural, and what to do about its failure
Robert Spekkens Perimeter Institute for Theoretical Physics
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Towards a mathematical theory of contextuality
Samson Abramsky University of Oxford
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Kochen-Specker contextuality: a hypergraph approach with operational equivalences
Ana Belen Sainz Gdańsk University of Technology
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The contextual fraction as a measure of contextuality
Shane Mansfield University of Edinburgh
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Nonlocality and contextuality as fine-tuning
Eric Cavalcanti Griffith University
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Experimental Quantum Foundations
5 talks-Collection Number C16034Talk
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Direct experimental reconstruction of the Bloch sphere
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Michael Mazurek Institute for Quantum Computing (IQC)
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Matthew Pusey University of York
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Single-photon test of Hyper-Complex Quantum Theories
Lorenzo Procopio University of Vienna
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Experimental implementation of quantum-coherent mixtures of causal relations
Robert Spekkens Perimeter Institute for Theoretical Physics
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Formulating and Finding Higher-Order Interference
9 talks-Collection Number C16018Talk
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Does relativistic causality constrain interference phenomena?
Markus Müller Institute for Quantum Optics and Quantum Information (IQOQI) - Vienna
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Time in Cosmology
14 talks-Collection Number C16016Talk
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Welcome and Opening Remarks
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Marina Cortes Institute for Astrophysics and Space Sciences
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Lee Smolin Perimeter Institute for Theoretical Physics
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Neil Turok University of Edinburgh
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The origin of arrows of time II
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Sean Carroll California Institute of Technology (Caltech) - Division of Physics Mathematics & Astronomy
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Marina Cortes Institute for Astrophysics and Space Sciences
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Tim Koslowski Technical University of Applied Sciences Würzburg-Schweinfurt
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The origin of arrows of time II cont.
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Sean Carroll California Institute of Technology (Caltech) - Division of Physics Mathematics & Astronomy
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Marina Cortes Institute for Astrophysics and Space Sciences
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Tim Koslowski Technical University of Applied Sciences Würzburg-Schweinfurt
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Testing time asymmetry in the early universe
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Brian Keating University of California, San Diego
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Andrew Liddle University of Lisbon
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Richard Muller University of California, Berkeley
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The fate of the big bang
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Abhay Ashtekar Pennsylvania State University
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Neil Turok University of Edinburgh
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Time as Organization – Downward Caustation, Structure and Complexity I
Barbara Drossel Technische Universität Darmstadt
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Time as Organization – Downward Caustation, Structure and Complexity II
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Stuart Kauffman Santa Fe Institute
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George Ellis University of Cape Town
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Concepts and Paradoxes in a Quantum Universe
44 talks-Collection Number C16015Talk
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Finally making sense of Quantum Mechanics, part 1
Yakir Aharonov Chapman University
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How to count one photon and get a(n average) result of 1000...
Aephraim Steinberg University of Toronto
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The Quantum Tip of the Two-Vector Iceberg
Avshalom Elitzur Israeli Institute for Advanced Research
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The arrow of time for continuous quantum measurements
Andrew Jordan University of Rochester
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Observation of Aharonov-Bohm effect with quantum tunneling
Yutaka Shikano Institute for Molecular Science, National Institutes of Natural Sciences
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Concepts and Paradoxes
11 talks-Collection Number C16008Talk
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Sudden Sharp Forces and Nonlocal Interactions
Yakir Aharonov Chapman University
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Protective Measurement and Ergodicity
Yakir Aharonov Chapman University
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Hopf Algebras in Kitaev's Quantum Double Models: Mathematical Connections from Gauge Theory to Topological Quantum Computing and Categorical Quantum Mechanics
18 talks-Collection 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 fault-tolerant 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.
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Contextuality: Conceptual Issues, Operational Signatures, and Applications
23 talks-Collection 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 Kochen-Specker 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 50-year 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 re-examined from a new information-theoretic 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.
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Experimental Quantum Foundations
5 talks-Collection Number C16034Experimental Quantum Foundations -
Formulating and Finding Higher-Order Interference
9 talks-Collection Number C16018Formulating and Finding Higher-Order Interference
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Concepts and Paradoxes in a Quantum Universe
44 talks-Collection Number C16015Concepts and Paradoxes in a Quantum Universe
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Partitions in quantum theory
Augustin Vanrietvelde Télécom Paris
The standard perspective on subsystems in quantum theory is a bottom-up, compositional one: one starts with individual "small" systems, viewed as primary, and composes them together to form larger systems. The top-down, decompositional perspective goes the other way, starting with a "large" system and asking what it means to partition it into smaller parts. In this talk, I will 1/ argue that the adoption of the top-down perspective is the key to progress in several current areas of foundational research; and 2/ present an integrated mathematical framework for partitions into three or more subsystems, using sub-C* algebras. Concerning the first item, I will explain how the top-down perspective becomes crucial whenever the way in which a quantum system is partitioned into smaller subsystems is not unique, but might depend on the physical situation at hand. I will display how that precise feature lies at the heart of a flurry of current hot foundational topics, such as quantum causal models, Wigner's friend scenarios, superselection rules, quantum reference frames, and debates over the implementability of the quantum switch. Concerning the second item, I will argue that partitions in (finite-dimensional) quantum theory can be naturally pinned down using sub-C* algebras. Building on simple illustrative examples, I will discuss the often-overlooked existence of non-factor C*-algebras, and how it leads to numerous subtleties -- in particular a generic failure of local tomography. I will introduce a sound framework for quantum partitions that overcomes these challenges; it is the first top-down framework that allows to consider three or more subsystems. Finally, as a display of this framework's technical power, I will briefly present how its application to quantum causal modelling unlocked the proof that all 1D quantum cellular automata admit causal decompositions.
(This is joint work with Octave Mestoudjian and Pablo Arrighi. This talk is complementary to my Causalworlds 2024 presentation, which will focus on the issue of causal decompositions.)
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics
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Lecture - Quantum Theory, PHYS 605
Bindiya Arora Perimeter Institute for Theoretical Physics