# Video Library

Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events 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 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.

## Hydrodynamic theory of transport in Dirac and Weyl semimetals

Wednesday Aug 24, 2016
Speaker(s):

I will discuss recent progress in understanding the consequences of hydrodynamic electron flow on measurable transport properties of metals, focusing on metals where the electrons behave as a charge neutral relativistic plasma. In graphene, I will connect our theoretical models with experimental data and show how we can explain features of transport in graphene that are inconsistent with quasiparticle transport. I will then discuss the extension of these results to Weyl semimetals, which are modeled by a system of multiple chiral fluids.

Scientific Areas:

## Superconducting quantum criticality of Dirac fermions

Wednesday Aug 24, 2016
Speaker(s):

The semimetal-superconductor quantum phase transition of 2D Dirac fermions, such as found on the surface of a topological insulator, is conjectured to exhibit an emergent N=2 supersymmetry, based on a one-loop renormalization group analysis. In this talk I will present further evidence for this conjecture based on a three-loop analysis.

Scientific Areas:

## Jogging Through Holographic Massive Gravity

Wednesday Aug 24, 2016
Speaker(s):

We present some recent developments in the framework of holographic (Lorentz violating) massive gravity.
We rigorously define the most generic isotropic setup in 3+1 dimensions and we study in detail its phenomenology.
We describe the electric and the viscoelastic responses of the system and we comment on the fate of the KSS viscosity bound
in absence of translational symmetry. We conclude with some discussion hints and comments for the future.

Scientific Areas:

## First sound of zero temperature holographic superfluids

Wednesday Aug 24, 2016

Within the context of AdS/CFT, the gravity dual of an s-wave superfluid is given by scalar QED on an asymptotically AdS spacetime. While this conclusion is vastly based on numerical arguments, I will provide an analytical proof that this is indeed the case. In particular, I will present a technique which allows to explicitely compute the low-energy effective action for the boundary theory starting from the bulk system. This will be done for an arbitrary number of dimensions and an arbitrary potential.

Scientific Areas:

## Hydrodynamic theory of fluctuating stripes

Wednesday Aug 24, 2016

I will present a hydrodynamic description of matter in a charge density wave (or "smectic") phase. As in superfluids, the spontaneous breaking of a continuous symmetry -- here translations in one direction -- adds a Goldstone phase to the usual long lived hydrodynamic variables. This phase propagates as a highly anisotropic "second sound" mode at low energies, affecting properties such as transport. Phase fluctuations, due to proliferating dislocations, give a finite life-time to certain collective modes, which can be experimentally probed e.g.

Scientific Areas:

## TBA

Wednesday Aug 24, 2016
Speaker(s):
Scientific Areas:

## Front End - Functions, "Functions", etc. - 2

Wednesday Aug 24, 2016

## Particle-Vortex duality and Topological Quantum Matter

Tuesday Aug 23, 2016
Speaker(s):
Scientific Areas:

## Universal Diffusion and the Butterfly Effect

Tuesday Aug 23, 2016
Speaker(s):

In 2014 Hartnoll proposed that the diffusion constants of incoherent metals should be bounded as $D \geq \hbar v^2/ (k_B T)$, where v is a characteristic velocity. In this talk I will describe a large class of holographic theories that saturate such a bound, with $v$ being the velocity of the butterfly effect. Our results suggest a novel connection between transport at strong coupling and the field of quantum chaos.

Scientific Areas:

## TBA

Tuesday Aug 23, 2016
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## Next Public Lecture

### BULLETPROOF CUSTARD: FLUIDS THAT STOP FLOWING WHEN YOU PUSH THEM TOO HARD

Wednesday Nov 02, 2016