Le contenu de cette page n’est pas disponible en français. Veuillez nous en excuser.

# Vidéotheque

Since 2002 Perimeter Institute has been recording seminars, conference talks, public outreach events such as talks from top scientists using video cameras installed in our lecture theatres.  Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities.

Recordings of events in these areas are all available and On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA)PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.

Accessibly by anyone with internet, Perimeter aims to share the power and wonder of science with this free library.

## Elliptic characteristic classes, bow varieties, 3d mirror duality

Mercredi mai 27, 2020
Speaker(s):

We study elliptic characteristic classes of natural subvarieties in some ambient spaces, namely in homogeneous spaces and in Nakajima quiver varieties. The elliptic versions of such characteristic classes display an unexpected symmetry: after switching the equivariant and the Kahler parameters, the classes of varieties in one ambient space coincide” with the classes of varieties in another ambient space. This duality gets explained as “3d mirror duality” if we regard our ambient spaces as special cases of Cherkis bow varieties. I will report on a work in progress with Y.

Scientific Areas:

## Quantum homeopathy works: Efficient unitary designs with a system-size independent number of non-Clifford gates

Mercredi mai 27, 2020
Speaker(s):

Many quantum information protocols require the implementation of random unitaries. Because it takes exponential resources to produce Haar-random unitaries drawn from the full n-qubit group, one often resorts to t-designs. Unitary t-designs mimic the Haar-measure up to t-th moments. It is known that Clifford operations can implement at most 3-designs. In this work, we quantify the non-Clifford resources required to break this barrier.

## Summer Undergrad 2020 - Symmetries (A) - Lecture 2

Mercredi mai 27, 2020
Speaker(s):

Continuous and discrete symmetries, infinitesimal symmetries

## Twisted superconformal algebras and representations of higher Virasoro algebras

Mercredi mai 27, 2020
Speaker(s):

(Super)conformal algebras on two-dimensional spacetimes play a ubiquitous role in representation theory and conformal field theory. In most cases, however, superconformal algebras are finite dimensional. In this talk, we introduce refinements of certain deformations of superconformal algebras which share many facets with the ordinary (super) Virasoro algebras. Representations of these refinements include the higher dimensional Kac—Moody algebras, and many more motivated by physics.

Scientific Areas:

## Summer Undergrad 2020 - Quantum Information - Lecture 2

Mercredi mai 27, 2020
Speaker(s):

## Codes, vertex algebras and topological modular forms

Mercredi mai 27, 2020
Speaker(s):

The talk illuminates the role of codes and lattice vertex algebras in algebraic topology. These objects come up naturally in connection with string structures or topological modular forms. The talk tries to unify these different concepts in an introductory manner.

Scientific Areas:

## Quasisymmetric characteristic numbers for Hamiltonian toric manifolds

Mardi mai 26, 2020
Speaker(s):

Baker and Richter's $A_\infty$ analog of the complex cobordism spectrum provides characteristic numbers for complex-oriented toric manifolds, which generalize to define similar invariants for Hamiltonian toric dynamical systems: roughly, the `completely integrable' systems of classical mechanics which (by KAM theory) possess remarkable stability properties. arXiv:1910.12609

Scientific Areas:

## Summer Undergrad 2020 - Numerical Methods (A) - Lecture 1

Mardi mai 26, 2020
Speaker(s):

Introduction to Ising model; review spin-1/2 and matrix representation of states  and operators; programming basics

## Casimir and free energy for free fields and holographic theories in 2+1 on curved spaces

Mardi mai 26, 2020
Speaker(s):

We investigate putting 2+1 free and holographic theories on a product of time with a curved compact 2-d space. We then vary the geometry of the space, keeping the area fixed, at zero/finite temperature, and measure the Casimir/free energy respectively. I will begin by discussing the free theory for a Dirac fermion or scalar field on deformations of the round 2-sphere. I will discuss how the Dirac theory may arise in physical systems such as monolayer graphene. For small deformations we solve analytically using perturbation theory.

Collection/Series:
Scientific Areas:

## The de Rham model for elliptic cohomology from physics

Mardi mai 26, 2020
Speaker(s):

I'll discuss elliptic cohomology from a physical perspective, indicating the importance of the Segal-Stolz-Teichner conjecture and joint work with D. Berwick-Evans on rigorously proving some of these physical predictions.

Scientific Areas:

## Lectures On-Demand

Watch on Perimeter's