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.
In terms of their energetics, cosmic ray protons are an insignificant by-product of star formation and super-massive black hole growth. However, due to their small mean free path, their coupling with the interstellar medium is absolute. In fact, they are most likely, the dominant source of momentum, and therefore kinetic force on galactic scales. By defining an Eddington Limit in Cosmic Rays, we show that the maximum photon luminosity of bright galaxies and quasars are capped by the production and subsequent expulsion of cosmic ray protons.
How many interacting quantum (field) theories of four-dimensional geometry are there which have General Relativity as their classical limit? Some of us still harbour hopes that a quantum theory of gravity is "reasonably unique", i.e. characterized by a finite number of free parameters. One framework in which such universality may manifest itself is that of "Quantum Gravity from Causal Dynamical Triangulations (CDT)".
A new force mediated by a new vector boson with mass in the MeV to GeV range and with very weak coupling to ordinary matter appears naturally in many theoretical models and could also explain a variety of observed anomalies. Such anomalies include the discrepancy between the predicted and the experimentally observed value for the muon anomalous magnetic moment, and recent cosmic-ray data that can be explained by dark matter interacting through this force with ordinary matter. This talk will review the motivation for such a force and present a broad array of probes of this physics.
Check back for details on the next lecture in Perimeter's Public Lectures Series