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Colloquium

This series covers all areas of research at Perimeter Institute, as well as those outside of PI's scope.

Seminar Series Events/Videos

Currently there are no upcoming talks in this series.

 

Mercredi mai 18, 2016
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100 years after the existence of gravitational waves was first postulated by Albert Einstein, the LIGO and Virgo Collaborations detected gravitational waves for the first time on September 14, 2015. The gravitational waves originated from a pair of black holes that merged over one billion years ago. The merger was so powerful that it shook the very fabric of space and sent a ripple across the Universe that we observed here on Earth at present day.

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Mercredi mai 11, 2016
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Recent developments in our understanding of black hole evaporation and the information paradox suggest that effects from quantum gravity are not necessarily hidden at the Planck scale. They might even one day be testable by gravitational wave measurements. To prepare ourselves, we must first understand what quantum gravity really means. Thankfully, we are pre-armed with a deep principle about gravity—that spacetime is really a hologram—and a powerful model for making this idea precise: gauge/gravity duality.

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Jeudi mai 05, 2016
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Entanglement is both a central feature of quantum mechanics and a powerful tool for studying quantum systems. Even empty spacetime is a highly entangled state, and this entanglement has the potential to explain puzzling thermodynamic properties of black holes. In order to apply the methods of quantum information theory to problems in gravity we have to confront a more fundamental question: what is a local subsystem, and what are its physical degrees of freedom?

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Mercredi mai 04, 2016
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Almost the first thing we learn as human beings is a sense of spatial awareness: the smaller the Euclidean distance between two objects, the closer they are. As adults, we apply this deeply held intuition to state space. In particular, as philosopher David Lewis made explicit in his seminal 1973 paper on Causation, we presume that one counterfactual world is closer to reality than another if this world resembles reality more than does the other. This intuition has guided the development of physical theory over the years.
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Mercredi avr 27, 2016
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Winds are driven by the gradients of solar heating. Vertical gradients cause thermal convection on the scale of the troposphere depth (less than 10 km). Horizontal gradients excite motions on a planetary (10000 km) and smaller scales. Weather is mostly determined by the flows at intermediate scale (hundreds of kilometers). Where these flows get their energy from? The puzzle is that three-dimensional small-scale motions cannot transfer energy to larger scales while large-scale planar motions cannot transfer energy to smaller scales.

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Lundi avr 25, 2016
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What are the bounds of the AdS/CFT correspondence? Which quantities in conformal field theory have simple descriptions in terms of classical anti-de Sitter spacetime geometry? These foundational questions in holography may be meaningfully addressed via the study of CFT correlation functions, which map to amplitudes in AdS. I will show that a basic building block in any CFT -- the conformal block -- is equivalent to an elegant geometric object in AdS, which moreover greatly streamlines and clarifies calculations of AdS amplitudes.

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Mardi avr 12, 2016

The coalescence of black hole-black hole (BHBH), black hole-neutron star (BHNS) and neutron star-neutron star (NSNS) systems are among the most promising sources of gravitational waves (GWs) detectable by Advanced LIGO/Virgo and NANOGrav. In addition, distinct observable electromagnetic radiation may accompany these GWs. Such "multi-messenger" sources can be powerful probes of fundamental physics such as the state of matter under extreme conditions, cosmology, as well as our theories of gravity.

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Mercredi avr 06, 2016
Speaker(s): 

Bott periodicity (1956) is a classical and old result in mathematics.

Its easiest incarnation of which concerns Clifford algebras. It says

that, up to Morita equivalence, the real Clifford algebras Cl_1(R),

Cl_2(R), Cl_3(R), etc. repeat with period 8. A similar result holds

for complex Clifford algebras, where the period is now 2. The modern

way of phrasing Bott periodicity in is terms of K-theory: I will

explain how one computes K-theory, and we will see the 8-fold Bott

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Mercredi mar 30, 2016
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Almost fifteen years after LIGO started listening to the cosmos, and 100 years after Einstein discovered general relativity, gravitational waves have been detected by ground-based interferometers, opening a new window on the universe. In this talk I will address some of the most exciting areas of research advanced LIGO will allow us to explore in the coming years. Detection and characterization of gravitational wave transients will be discussed, as well as their impact on astrophysics.

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