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.
Space-time symmetries are a crucial ingredient of any theoretical model in physics. Unlike internal symmetries, which may or may not be gauged and/or spontaneously broken, space-time symmetries do not admit any ambiguity: they are gauged by gravity, and any conceivable physical system (other than the vacuum) is bound to break at least some of them.
Vortex lines are a distinctive feature of superfluids and are characterized by a very peculiar dynamics. In this talk, I will first discuss the behavior of vortex lines in a non-relativistic superfluids in the incompressible limit. I will then introduce an effective theory of vortex lines coupled to sound which applies to relativistic superfluids. I will conclude by briefly discussing the similarities between the effective theory for vortex lines and non-relativistic General Relativity.
Modern materials abound in systems to which the quasiparticle picture does not apply, and developing their theoretical description remains an important challenge in condensed matter physics. I will describe recent progress in understanding the dynamics of two systems without quasiparticles: (i) ultracold atoms in optical lattices, and (ii) the nematic quantum critical point of metals with applications to the `strange metal’ found in the high temperature superconductors. A combination of field-theoretic, holographic, and numerical methods will be used.
Brian Swingle obtained his PhD from MIT in 2011 and then moved to Harvard, where he is currently a Simons Fellow in condensed matter physics. Swingle is interested in the physics of quantum matter, and especially in the interface between condensed matter physics, quantum information science, and gravity and holography.
Recently its has been found that relativistic hydrodynamics requires modifications in the presence of quantum anomalies. We will follow the theoretical developments that leads to this discovery and look at modern applications of hydrodynamics with anomalies.
Spontaneous Symmetry Breaking is a very universal concept applicable for a wide range of subjects: crystal, superfluid, neutron stars, Higgs boson, magnets, and many others. Yet there is a variety in the spectrum of gapless excitations even when the symmetry breaking patterns are the same. We unified all known examples in a single-line Lagrangian of the low-energy effective theory.
This hour will be devoted to a description of quantum turbulence,that is turbulence in superfluids. The first talk (~20 minutes) will be given by Russell Donnelly. He will describe briefly the problem of classical turbulence and how turbulence in superfluids is different. The second talk will be given by Carlo Barenghi who will discuss progress in the simulation of quantum turbulence which is capable of suggesting insights so far inaccessible to experiment.
I will discuss the enhancement of space-time symmetries to Lorentz (rotation) invariance at the renormalization group fixed points of non-relativistic (anisotropic) field theories. Upon describing examples from the condensed matter physics, I will review the general argument for the stability of the infrared fixed points with the enhanced symmetry. Then I will focus on unitary field theories in (1+1) space-time dimensions which are invariant under translations, isotropic scale transformations and satisfy the requirement that the velocity of signal propagation is bounded from above.
In the past few years substantial evidence has been collected that points to coexistence of charge correlations with long range superconductivity in underdoped cuprate superconductors. In this talk I will review some of this evidence, then show that a charge density wave with precisely the same signatures is a natural instability of an antiferromagnetic metal, and finally derive some phenomenological consequences, with special focus on quantum oscillation experiments.