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.
After giving
an overview of the basic features of Horava gravity, I will focus on the latest developments and argue that, at least for the most general and complete version of the theory, the infrared phenomenology is by now relatively well understood and pathologies have been tamed. This implies that time has come for the theory to face a new series of intriguing challenges, related to quantization, ultraviolet phenomenology, black holes and singularities etc. I will present some ideas and first results in some of these directions.
Abstract The magic state model of quantum computation gives a recipe for universal quantum computation using perfect Clifford operations and repeat preparations of a noisy ancilla state. It is an open problem to determine which ancilla states enable universal quantum computation in this model. Here we show that for systems of odd dimension a necessary condition for a state to enable universal quantum computation is that it have negative representation in a particular quasi-probability representation which is a discrete analogue to the Wigner function.
Mass, a concept familiar to all of us, is also
one of the deepest
mysteries in nature. Almost all of the mass in the
visible universe,
you, me and any other stuff that we see around us, emerges from a
quantum field theory, called QCD, which has a completely negligible
microscopic mass content. How does QCD and the family of
gauge
theories it belongs to generate a mass?
This class of non-perturbative problems remained largely elusive despite much