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.
Much effort has been devoted to the study of systems with
topological order, motivated by practical issues as well as more field
theoretical and mathematical concerns. This talk will give an overview of some
of the field, describing abelian systems relevant to the search for spin
liquids, and non-abelian systems relevant to topological quantum computation. I
will focus in particular on problems not reducible to free-fermion ones;
examples include the RVB state of electrons as well as models of quantum loops
and nets.
A very general way of describing the abstract structure of quantum theory is to say that the set of observables on a quantum system form a C*-algebra. A natural question is then, why should this be the case - why can observables be added and multiplied together to form any algebra, let alone of the special C* variety? I will present recent work with Markus Mueller and Howard Barnum, showing that the closest algebraic cousins to standard quantum theory, namely the Jordan-algebras, can be characterized by three principles having an informational ﬂavour, namely: (1) a generalized spectral de
There is evidence for a 130 GeV gamma-ray line at the Galactic Center in the Fermi Large Area Telescope data. Dark matter candidates that explain this feature should also annihilate to Standard Model particles, resulting in a continuous spectrum of photons. To study this continuum, we analyze the Fermi data down to 5 GeV, restricted to the inner 3 degrees of the Galaxy. We place a strong bound on the ratio of continuum photons to monochromatic line photons that is independent of uncertainties in the dark matter density profile.
Tidal stripping of dark matter from subhalos falling into the Milky Way produces narrow, cold tidal streams as well as more spatially extended ``debris flows'' in the form of shells, sheets, and plumes.Here we focus on the debris flow in the Via Lactea II simulation, and show that this incompletely phase-mixed material exhibits distinctive high velocity behavior. Unlike tidal streams, which may not necessarily intersect the Earth's location, debris flow is spatially uniform at 8 kpc and thus guaranteed to be present in the dark matter flux incident on direct detection experiments.
Amorphous materials (glasses) probably
constitute >90% of the solid matter surrounding us in everyday life,yet
traditional textbooks of condensed matter physics devote virtually no space to
them.Crudely speaking,the puzzles in the behavior of glasses can be divided
into three major areas:the glass transition itself,the characteristic long-term
memory effects and the near-equilibrium thermal,dielectric and transport
properties;this talk focusses entirely on the third area.Over the last 40 years
TBA
A simple physical realization of an integer quantum Hall
state of interacting two dimensional bosons is provided. This is an example of
a "symmetry-protected topological" (SPT) phase which is a
generalization of the concept of topological insulators to systems of
interacting bosons or fermions. Universal physical properties of the boson
integer quantum Hall state are described and shown to correspond to those
expected from general classifications of SPT phases.
I will briefly review topological phases of non
interacting fermions, such as topological insulators, and discuss how ideas
from quantum information, in particular the entanglement spectrum, can be used
to characterize them.
We discuss the shortcomings of Einstein gravity at both the classical and quantum levels. We discuss the motivation for replacing Einstein gravity by conformal gravity. We show how the conformal gravity theory is able to naturally solve the quantum gravity problem, the vacuum zero-point energy problem, the vacuum zero-point pressure problem, the cosmological constant problem, and the dark matter problem.
Check back for details on the next lecture in Perimeter's Public Lectures Series