Format results

17 talksCollection NumberC18007
Talk


Quantum speedup in testing causal hypotheses
University of Hong Kong (HKU) 
The Logic of Physical Law
Università della Svizzera italiana 
When Causality Is Relaxed: Classical Correlations, Computation, and Time Travel
University of Vienna 
On the concepts of universality in physics and computer science
Universität Innsbruck 
A nogo theorem for observerindependent facts
Institute for Quantum Optics and Quantum Information (IQOQI)  Vienna 

Algorithmic information theory: a critical perspective
LudwigMaximiliansUniversitiät München (LMU)


Observers in Quantum and Foil Theories
11 talksCollection NumberC18006Talk


Compatibility of implicit and explicit observers in quantum theory and beyond
Institute for Quantum Optics and Quantum Information (IQOQI)  ViennaPIRSA:18040084 
From observers to physics via algorithmic information theory I
Institute for Quantum Optics and Quantum Information (IQOQI)  ViennaPIRSA:18040078 
From observers to physics via algorithmic information theory II
Institute for Quantum Optics and Quantum Information (IQOQI)  ViennaPIRSA:18040080 
Motility of the internalexternal cut as a foundational principle
Perimeter Institute for Theoretical PhysicsPIRSA:18040073 




Open Research: Rethinking Scientific Collaboration
11 talksCollection NumberC18005Talk


Data Mists, Blockchain Republics, and the Moon Shot
Indiana University 
Like penguins on an ice floe: The scary business of adopting open science practices
Alexander von HumboldtStiftung 


What’s not to like? Open science will fail unless it takes the costs seriously
University of British Columbia 



Gauge Theory, Geometric Langlands and Vertex Operator Algebras
11 talksCollection NumberC18004Talk

Gauge Theory, Geometric Langlands, and All That
Institute for Advanced Study (IAS)  School of Natural Sciences (SNS) 
Overview of the global Langlands correspondence
University of WisconsinMilwaukee 
Gauge theory, vertex algebras and quantum Geometric Langland dualities
Perimeter Institute for Theoretical Physics 

Introduction to local geometric Langlands
The University of Texas at Austin 




The Path Integral for Gravity
18 talksCollection NumberC17057Talk

Welcome and Opening Remarks
University of Edinburgh 
The significance of the proper time in the quantum mechanics of the gravitational field.
Centro de Estudios Científicos (CECs) 
TBA
LudwigMaximiliansUniversität München (LMU) 
Semiclassical evaluation of the 3D gravity path integral and quasilocal holography
Perimeter Institute for Theoretical Physics 

An asymptotically safe point of view on the gravitational path integral
University of Southern Denmark 
The path integral for gravity and Fedosov quantization
Universität Leipzig 
Surprises in the Path Integral for Gravity
University of Edinburgh


Quantum Black Holes in the Sky?
34 talksCollection NumberC17055Talk

Quantifying the evidence for black holes with GW and EM probes
Instituto Superior Tecnico  Departamento de Física 
Echoes from the Abyss: Tentative Evidence for PlanckScale Structure at Black Hole Horizons
University of Stavanger (UiS) 
Improvements on the methods for searching echoes
Albert Einstein Institute 
A modelindependent search for gravitationalwave echoes
Institucio Catalana de Recerca I Estudis Avancats (ICREA)  Universitat de Barcelona 
An alternative significance estimation for the evidence for echoes
Albert Einstein Institute 
Discussion: Evidence for Echoes
PIRSA:17110074 
Inspiral Tests of Strongfield Gravity and Ringdown Tests of Quantum Black Holes
University of Virginia 
A Recipe for Echoes
The University of Texas at Austin


Experimental techniques in tabletop fundamental physics
24 talksCollection NumberC17030Talk

Welcome and Opening Remarks
Perimeter Institute for Theoretical Physics 
Theory Talk
Perimeter Institute for Theoretical Physics 
A threedimensional optical lattice clock: precision at the 19th digit
University of Colorado Boulder 
Measurement of the fine structure constant as a test of the standard model
University of California, Berkeley 
Superconducting accelerometer technology for precision tests of gravitation and search for new interactions
University of Maryland, College Park 
Searching for axions and new shortrange forces with resonant sensors
University of Nevada Reno 
Testing Gravity at Extreme Scales
Stanford University 
Precision Physics in Storage Rings
Institute for Basic Science  Center for Axion and Precision Physics Research


Talk

Semisimple Hopf algebras and fusion categories
Universidad de los Andes 
The Hopf C*algebraic quantum double models  symmetries beyond group theory
Freie Universität Berlin 
Modular categories and the Witt group
Radboud Universiteit Nijmegen 
Topological Quantum Computation
Texas A&M University 
Gapped phases of matter vs. Topological field theories
Perimeter Institute for Theoretical Physics 
An Introduction to Hopf Algebra Gauge Theory
University of ErlangenNuremberg 
Kitaev lattice models as a Hopf algebra gauge theory
University of ErlangenNuremberg 
Topological defects and highercategorical structures
Karlstad University


Contextuality: Conceptual Issues, Operational Signatures, and Applications
23 talksCollection NumberC17027Talk

Welcome and Opening Remarks
Perimeter Institute for Theoretical Physics 
Quantum Mechanics in a New Key
Princeton University 
What do we learn about quantum theory from KochenSpecker quantum contextuality?
Universidad de Sevilla 
Noncontextuality: how we should define it, why it is natural, and what to do about its failure
Perimeter Institute for Theoretical Physics 
Towards a mathematical theory of contextuality
University of Oxford 
KochenSpecker contextuality: a hypergraph approach with operational equivalences
Gdańsk University of Technology 
The contextual fraction as a measure of contextuality
University of Edinburgh 
Nonlocality and contextuality as finetuning
Griffith University


New Directions in Dark Matter and Neutrino Physics
28 talksCollection NumberC17026Talk


CRESST Detectors for Dark Matter and Neutrino Physics
Max Planck Institute 
Getting the Most out of Liquid Xenon
Columbia University 


Direct detection signals of light dark matter
University of Vienna 



Bounce Scenarios in Cosmology
16 talksCollection NumberC17024Talk

Welcome and Opening Remarks

University of Sheffield

University of Edinburgh


Bounce in Loop Quantum Cosmology and its Implications
Pennsylvania State University 
Observable Consequences of a Bounce
Canadian Institute for Theoretical Astrophysics (CITA) 
Challenges for Bouncing Cosmologies
McGill University  Department of Physics 
Emergent bouncing cosmology from quantum gravity condensates
University of New Brunswick 
Discussion Session 2

TotalEnergies (France)

University of Sheffield

Arthur B. McDonald Canadian Astroparticle Physics Research Institute





Making Quantum Gravity Computable
31 talksCollection NumberC17023Talk

Welcome and Opening Remarks
Perimeter Institute for Theoretical Physics 
Introduction to Monte Carlo methods  1
Utrecht University 
Introduction to Monte Carlo methods  2
Utrecht University 
Introduction to Tensor Network methods  1
Alphabet (United States) 
Introduction to Tensor Network methods  2
Alphabet (United States) 
Tutorial: Introduction to Monte Carlo Methods

Utrecht University

Radboud Universiteit Nijmegen


Tutorial: Introduction to Tensor Network methods

Alphabet (United States)

Institut des Hautes Etudes Scientifiques (IHES)


Scientific Computing and Computational Science
Perimeter Institute for Theoretical Physics


Algorithmic Information, Induction and Observers in Physics
17 talksCollection NumberC18007Our universe is of astonishing simplicity: almost all physical observations can in principle be described by a few theories that have short mathematical descriptions. But there is a field of computer science which quantifies simplicity namely algorithmic information theory (AIT). In this workshop we will discuss emerging connections between AIT and physics some of which have recently shown up in fields like quantum information theory and thermodynamics. In particular AIT and physics share one goal: namely to predict future observations given previous data. In fact there exists a gold standard of prediction in AIT called Solomonoff induction which is also applied in artificial intelligence. This motivates us to look at a broader question: what is the role of induction in physics? For example can quantum states be understood as Bayesian states of belief? Can physics be understood as a computation in some sense? What is the role of the observer i.e. the agent that is supposed to perform the predictions? These and related topics will be discussed by a diverse group of researchers from different disciplines.

Observers in Quantum and Foil Theories
11 talksCollection NumberC18006Foil theories sometimes called mathematically rigorous science fiction describe ways the world could have been were it not quantum mechanical. Our understanding of quantum theory has been deepened by contrasting it with these alternatives. So far observers in foil theories have only been modeled implicitly for example via the recorded probabilities of observing events. Even when multiagent settings are considered these agents tend to be compatible in the classical sense that they could always compare their observations. Scenarios where agents and their memories are themselves modeled as physical systems within the theory (and could in particular measure each other as in Wigner's friend experiment) have not yet been considered. In this workshop we will investigate which foil theories allow for the existence of explicit observers and whether they allow for paradoxes in multiagent settings such as those found in quantum theory. We will also investigate which interpretations of quantum theory would equally well interpret the foil theories and which interpretations are truly quantum. We will gain a deeper understanding of how this can happen by discussing appropriate definitions observers in these theories and seeing how such observers learn about their environment.

Open Research: Rethinking Scientific Collaboration
11 talksCollection NumberC18005Scientific inquiry in the 21st century is beset with inefficiencies: a flood of papers not read theories not tested and experiments not repeated; a narrow research agenda driven by a handful of highimpact journals; a publishing industry that turns public funding into private profit; the exclusion of many scientists particularly in developing countries from cuttingedge research; and countless projects that are not completed for lack of skilled collaborators. These are all symptoms of a major communication bottleneck within the scientific community; the channels we rely on to share our ideas and findings especially peerreviewed journal articles and conference proceedings are inadequate to the scale and scope of modern science. The practice of open research doing science on a public platform that facilitates collaboration feedback and the spread of ideas addresses these concerns. Opensource science lowers barriers to entry catalyzing new discoveries. It fosters the realtime sharing of ideas across the globe favoring cooperative endeavor and complementarity of thought rather than wasteful competition. It reduces the influence of publishing monopolies enabling a new credit attribution model based on contributions made rather than references accrued. Overall it democratizes science while creating a new standard of prestige: quality of work instead of quantity of output. This workshop will bring together a diverse group of researchers from fields as diverse as physics biology computer science and sociology committed to opensource science. Together we will review the lessons learnt from various pioneering initiatives such as the Polymath project and Data for Democracy. We will discuss the opportunity to build a new tool similar to the software development platform GitHub to enable online collaborative science. We will consider the challenges associated with the adoption of such a tool by our peers and discuss ways to overcome them. Finally we will sketch a roadmap for the actual development of that tool.

Gauge Theory, Geometric Langlands and Vertex Operator Algebras
11 talksCollection NumberC18004The workshop will explore the relation between boundary conditions in fourdimensional gauge theory the Geometric Langlands program and Vertex Operator Algebras.

The Path Integral for Gravity
18 talksCollection NumberC17057Over the past three decades, the idea of a path integral over geometries, describing gravity in various dimensions, has become increasingly central to many areas of theoretical physics, including string and Mtheory, holography and quantum aspects of black holes and cosmology.
In each of these areas, the path integral is frequently invoked as a formal device although, as practitioners will admit, except in very special cases the basic formula remains undefined. Typically, classical saddle points are discussed, whether real or complex, but the required integrals are left unperformed.
This state of affairs is untenable because it leaves the theory on a shaky footing and hence does not permit a sound comparison of theoretical predictions with observations. The time has come to critically reassess the foundational ideas of the path integral for gravity, including its definition, evaluation and interpretation; to identify problems with
existing uses and claims based on it, and to seek improvements. The workshop will focus on the continuum theory and its semiclassical limit, with applications to cosmology, black holes and holography. In particular, the notion of a “Euclidean path integral” for a “wavefunction of the universe” will be addressed.To this effect we intend to revisit discussion of “quantum geometrodynamics” from the path integral viewpoint and to pursue various applications. The developments in this direction that took place in the late 1970's and early 1980's were not incorporated in subsequent efforts, where the emphasis shifted to using a classical background with quantum fluctuations superimposed on it, a split which although useful in particular approximations can hardly be imagined to lie at the foundation of the theory. The revival of the discussion of the foundation of the path integral for gravity is made timely, we believe, by the introduction of new global methods such as PicardLefschetz theory.
The format of the workshop will be unusual. For the first three days, the mornings will begin with a longer, introductory lecture by each of the three organisers, setting out some of the foundational issues. This will be followed by shorter lectures by the participants, tackling the same foundational questions. The morning lectures, held in the Bob room, will be open to all Perimeter residents and visitors. They will be recorded and made available for viewing on PIRSA. Afternoons will be devoted to friendly and informal discussions, with participants invited to offer short contributions which follow up or develop points raised in the mornings, within a relaxed and highly conducive environment. Participation in these afternoon discussion sessions, as well as social events associated with the workshop, will be limited to registered workshop participants. The last two days of the workshop will be an opportunity for participants to continue discussions on topics which emerge as of greatest general interest, as well as to follow up in smaller groups on technical points or new ideas.

Quantum Black Holes in the Sky?
34 talksCollection NumberC17055The past decade has witnessed significant breakthroughs in understanding the quantum nature of black holes, with insights coming from quantum information theory, numerical relativity, and string theory. At the same time, astrophysical and gravitational wave observations can now provide an unprecedented window into the phenomenology of black hole horizons. This workshop seeks to bring together leading experts in these fields to explore new theoretical and observational opportunities and synergies that could improve our physical understanding of quantum black holes.

Experimental techniques in tabletop fundamental physics
24 talksCollection NumberC17030In the last few years there has been a resurgence of interest in small scale high sensitivity experiments that look for new forces and new particles beyond the Standard Model. They promise to expand our understanding of the Cosmos and possibly explain mysteries such as Dark matter in a way that is complementary to colliders and other large scale experiments. There is a number of different physics motivations and approaches currently being explored in many ongoing and newly proposed experiments and they often share common experimental techniques.Many workshops in this field focus on the theory motivations behind these experiments without emphasis on the details of the experimental techniques that enable precision measurements. There is also substantial experimental expertise across many fields, often outside of fundamental physics community, that can be relevant to ongoing and proposed experiments.Thus, we decided to organize the workshop around some of the common experimental techniques. We hope it will be educational for both experimentalists and theorists and lead to discussions on the best way forward. We would like to bring together experimentalists with different expertise in the hope that it will lead to new ideas through interdisciplinary interactions. For theorists, we expect it to provide better appreciation of the challenges and opportunities in improving the sensitivity of precision measurement experiments.

Hopf Algebras in Kitaev's Quantum Double Models: Mathematical Connections from Gauge Theory to Topological Quantum Computing and Categorical Quantum Mechanics
18 talksCollection NumberC17029The 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 NumberC170272017 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.

New Directions in Dark Matter and Neutrino Physics
28 talksCollection NumberC17026Continuing investment in fundamental weaklycoupled science, primarily through neutrino experiments and dark matter searches, prompts the question: is the maximum possible scientific information going to be extracted from these experiments? Are there new creative uses of the existing and planned facilities that would advance our knowledge of fundamental physics? Are there physics targets that have been overlooked by the current approach? This workshop will attempt to advance discussion of these topics, and concentrate on nontraditional ideas and alternative methods of probing new physics, both at underground laboratories and at highintensity accelerators. The workshop aims to complement the large international conference, Topics in Astroparticle and Underground Physics 2017, to be held in Sudbury ON July 2428, by directly preceding that meeting.


Making Quantum Gravity Computable
31 talksCollection NumberC17023Making Quantum Gravity Computable