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.
Information has always been valuable, never more so than in recent decades, and throughout history people have turned to cryptography in an attempt to keep important information secret. New technologies are now emerging based on the counterintuitive laws of quantum physics that govern the atomic scale. These technologies threaten cryptographic methods which are in widespread use today, but offer new quantum cryptographic protocols which could profoundly alter the world of cryptography.
The refinement of our understanding of Space and Time through thought experiments; starting with Newtonian ideas and ending with the mathematical adventures of Einstein and other prominent scientists as they contemplate the structure of stars.
The reason cosmologists have a job is that the Universe as a whole -- the stuff between planets and stars and galaxies -- is, despite first appearances, a pretty interesting place. The strangest fact about it is that it's expanding, and always has been, as far as we know (and though Einstein's theory of gravity predicts this, Albert himself didn't much care for the idea, at least at first). After about seventy years -- it was discovered in 1929 -- this expansion was kind of old hat, but then new observations came around that shattered the old complacency.
Classical physics of a spinning bar magnet in an external magnetic field: energy, angular momentum, torque and its effect on angular momentum, and precession. Application to NMR (Nuclear Magnetic Resonance). The peculiar physics and mathematics of quantum mechanical spin: quantization of spin and superposition of spin states. Application of quantum mechanical spin and NMR to quantum computing..
Physics emerged from the twentieth century with two remarkably successful descriptions of nature which stand in striking contrast. Quantum mechanics describes the subatomic realm with intrinsic uncertainties and probabilities. On the other hand, Einstein's general relativity describe gravitational phenomena in an exacting geometric arena. Theoretical physicists have struggled for over fifty years trying to combine these views in a single unified framework. More recently, superstring theory has drawn a huge amount of interest as a leading contender to provide such a unification.
The normalized-state spaces of finite-dimensional Jordan algebras constitute a relatively narrow class of convex sets that includes the finite-dimensional quantum mechanical and classical state spaces. Several beautiful mathematical characterizations of Jordan statespaces exist, notably Koecher's characterization as the bases of homogeneous self-dual cones, and Alfsen and Shultz's characterization based on the notion of spectral convex sets plus additional axioms.
The Quantum Bayesianism of Caves, Fuchs and Schack presents a distinctive starting point from which to attack the problem of axiomatising - or re-constructing - quantum theory. However, many have had the doubt that this starting point is itself already too radical. In this talk I will briefly introduce the position (it will be familiar to most, no doubt) and describe what I take to be its philosophical standpoint. More importantly, I shall seek to defend it from some bad objections, before going on to level some more substantive challenges.
Quantum Mechanics (QM) is a beautiful simple mathematical structure--- Hilbert spaces and operator algebras---with an unprecedented predicting power in the whole physical domain. However, after more than a century from its birth, we still don't have a "principle" from which to derive the mathematical framework. The situation is similar to that of Lorentz transformations before the advent of the relativity principle.