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.
Bell's theorem shows that our intuitive understanding of causation must be overturned in light of quantum correlations. Nevertheless, quantum mechanics does not permit signalling and hence a notion of cause remains. Understanding this notion is not only important at a fundamental level, but also for technological applications such as key distribution and randomness expansion. It has recently been shown that a useful way to determine which classical causal structures give rise to a given set of correlations is to use entropy vectors.
The fundamental constants of our universe may have been set to maximize the production of similar universes, through repeated parametric variation. In this context, I will advocate that by the time the maximum entropy producer in our universe has reached maximum complexity, the majority of its energy should be re-purposed towards the production of additional universes. This builds on elements of prior proposals, including cosmological natural selection, the nonsingular universe, and the causal entropic principle.
If we want a mechanism for the current cosmic expansion that is alternative to (and possibly more “natural” than) the cosmological constant, there exist intriguing proposals within the dark energy and modified gravity realm.
First, I will briefly review the status of one of the most promising ideas, massive gravity: cosmological solutions, some formal aspects and recent developments. Then, I will present recent work aimed at constraining such models with LSS probes.