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.
Quantum Gravity at the origin of seeds of cosmic
structure?
One century after the seminal balloon flights of Victor Hess, the Pierre Auger Observatory aims at unveiling some of the mysteries of the highest-energy cosmic rays: what are their sources? Is there an end to the spectrum? What kind of particles are they? Are there signatures of new physics or of a violation of fundamental laws of physics? The Auger Observatory measures cosmic rays with energies of 10^20 eV or more by observing the giant air showers created when the particles hit the atmosphere.
Asymptotically safe inflation and CMB polarization
The presence of complex critical exponents in the scaling behavior of the Newton constant and Cosmological constant has dramatic consequences at the inflation scale. In particular an infinite number of unstable de-Sitter vacua emerges from an effective quantum gravitational action. In this framework, the possibility of detecting specific signaturesof a non-gaussian fixed point of the gravitational interactions in the CMB polarization spectrum will then be discussed.
The high flux and variability of the blazar PKS 2155-304 as observed by H.E.S.S. during the night of 28 July 2006 allowed a very high precision search for Quantum Gravity-induced energy-dependent time lags. In this talk, I will review the results published by the H.E.S.S. collaboration on this topic. In particular, I will emphasize the latest results obtained using a likelihood fit to study individual photon data.
Naturalness problems that could be signaling the necessity a completion of an effective field theory with the introduction of an otherwise overlooked ingredient. The cosmological constant problem can be seen as a signal that the EFT for gravity, general relativity, is not correctly including the gravitational properties of the vacuum.
Analogue models of gravity have been a test field for many phenomena in quantum field theory on curved spacetimes. It was recently recognized that in some situations they can also provide toy models of emergent gravity. We shall review here such a model and address within it the nature and scale of the cosmological constrant trying to draw general lessons for emergent gravity scenarios.
Current approaches to the problems of dark energy and unification generically predict the existence of new fields (quintessence dilatons etc.) that will in principle couple with different strengths to different standard-model fields. These different coupling strengths will cause test materials of different compositions to fall at different rates in the same gravitational field violating the Equivalence Principle the foundation of General Relativity.