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.
Actions for gravity: the Einstein-Hilbert action - 3D gravity - first order formalism of 3D gravity (triads and connections)
The 21st century may come to be known as the Age of Photonics, as we exploit our ability to make and manipulate light as an amazing carrier of energy and information. From quantum computing and entanglement to eye surgery and solar energy, humans are already reaping the benefits of our own endeavours to understand and control light.
The Leggett-Garg (LG) inequalities were introduced, as a temporal parallel of the Bell inequalities, to test macroscopic realism -- the view that a macroscopic system evolving in time possesses definite properties which can be determined without disturbing the future or past state. The talk will begin with a review of the LG framework. Unlike the Bell inequalities, the original LG inequalities are only a necessary condition for macrorealism, and are therefore not a decisive test.
Many of the rich interactions between mathematics and physics arise using general mathematical frameworks that describe a host of physical phenomena: from differential equations, to algebra, to topology and geometry. On the other hand, mathematics also possesses many examples of "exceptional objects": they constitute the finite set of leftovers that appear in numerous classification problems.
CPTP maps POVMs. Measures of distance: fidelity and trace distance.
Example of the parametrized particle: Canonical analysis - Physical phase space and Dirac observables. The Dirac program: the program - case of the parametrized particle.
It is known that there is a relationship between conformal Carroll transformations and BMS symmetry. In this talk I will explore the geometry of generic Carroll structures which may be thought of as the basic underlying geometric structure on null hypersurfaces. A Carroll structure can be thought of as a fibre bundle with Ehresmann connection, and one finds that (generalized) BMS symmetry emerges as the conformal symmetry of this bundle and connection. I’ll briefly also describe how this story fits into the physics of ’soft modes.’
Mirror sectors -- hidden sectors that are approximate copies of the Standard Model -- are a generic prediction of many models, notably the Mirror Twin Higgs model. Such models can have a rich cosmology and many interesting detection signatures beyond the realm of colliders. In this talk, I will focus on the possibility that mirror matter can form stars which undergo mirror nuclear fusion in their cores. I will discuss the mechanisms by which these objects can emit Standard Model light and estimate their luminosity and prospects for their detection.