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 November 1919 the British scientific community announced the confirmation of Einstein\'s prediction for the bending of light by the suns gravitational field. This announcement made sensational headlines in British and American papers, and soon thereafter Einstein was thrust into the stratosphere of stardom. To appreciate this phenomenon requires taking a closer look at the role of leading image makers of the day, particularly in Weimar era Germany.
Morality defined Albert Einsteins sense of social obligation and political justice. It thrust on him a lifelong sense of responsibility for the defenceless and the underprivileged. At the same time, his jealously guarded independence dictated a kind of splendid isolation that made him indifferent to the temptations of political influence. How did this sense of commitment arise? What were the sources of his fierce independence? How did he resolve the contradiction?
One of the most hotly debated topics of the late nineteenth century concerned the geometry of physical space, an issue that arose with the discovery of non-Euclidean geometries. Lobachevsky and Bolyai opened the way, but it was not until the 1860s that scientists began to take this revolutionary theory seriously. Assuming the free mobility of rigid bodies, Helmholtz concluded that the geometry of space was Euclidean or else of constant curvature (either positive of negative).
What was happening in Philosophy in 1905? This lecture will seek to answer that question by picking out some of the most influential works of philosophy that were published in or shortly before that year, describing both those works themselves and their intellectual context. The works discussed will include Henri Poincare\'s Science and Hypothesis, Edmund Husserl\'s Logical Investigations, Gottlob Frege\'s Fundamental Laws of Arithmetic and Bertrand Russell\'s \'On Denoting\'.
We show that the entropy resulting from the counting of microstates of non extremal black holes using field theory duals of string theories can be interpreted as arising from entanglement. The conditions for making such an interpretation consistent are discussed. First, we interpret the entropy (and thermodynamics) of spacetimes with non degenerate, bifurcating Killing horizons as arising from entanglement. We use a path integral method to define the Hartle-Hawking vacuum state in such spacetimes and discuss explicitly its entangled nature and its relation to the geometry.
In 1905, Norwegian explorer Roald Amundsen completed the first ever transit of the fabled Northwest Passage, culminating a centuries long quest that had claimed ships and lives. Amundsen\'s feat was one of many human achievements in the first decade of the new century, and a landmark in the history exploration. Amundsen\'s voyage was preceded by the controversial North Pole expedition of Robert Peary, another long sought prize of explorers.