Talks

A charged particle can detect the presence of a magnetic field confined into a solenoid. The strength of the effect depends only on the phase shift experienced by the particle's wave function, as dictated by the Wilson loop of the Maxwell connection around the solenoid. In this seminar I'll show that Loop Gravity has a structure analogous to the one relevant in the Aharonov-Bohm effect described above: it is a quantum theory of connections with curvature vanishing everywhere, except on a 1d network of topological defects. Loop states measure the flux of the gravitational magnetic field through a defect line. A feature of this reformulation is that the space of states of Loop Gravity can be derived from an ordinary QFT quantization of a classical diffeomorphism-invariant theory defined on a manifold. I'll discuss the role quantum geometry operators play in this picture, and the perspective of formulating the Spin Foam dynamics as the local interaction of topological defects.

The Large Hadron Collider (LHC) is now running (after a rocky start). This talk reviews why the start was rocky and how this constrains the physics program over the next few years. I will briefly survey how 'naturalness' arguments argue why something should be discovered, and why theoretical proposals fall into three main categories. If time permits I will close by telling you why I think the cosmological constant problem implies the LHC will strike paydirt and make quantum gravity an experimental science.

We perform an exact localization calculation for the expectation value of Wilson-'t Hooft line operators in N=2 gauge theories on S^1 x R^3. The expectation values form a quantum mechanically deformed algebra of functions on the Hitchin moduli space by Moyal multiplication. We demonstrate that these expectation values are the Weyl transform of the Verlinde operators, which acts on conformal blocks as difference operators. Our results are also in exact match with the predictions from wall-crossing in the IR effective theory.

With a background in computer and systems engineering as well as language processing and automatic speech recognition, Ms. Payette was selected from a pool of 5,330 candidates to become a Canadian astronaut, focusing on technical issues in robotics. Today, following her amazing professional career and numerous life experiences, Ms. Payette is veteran of two missions to the International Space Station as a crew member and Flight Engineer. She also holds a commercial pilot license; earned military pilot captaincy on the 'Snowbird' jets; is a certified deep-sea diving suit operator; is fluent in French and English, and can converse in Spanish, Italian, Russian and German. She has received many awards, holds numerous degrees and, on a personal note, plays the piano and has sung with the Montreal Symphony Orchestra, the Piacere Vocale in Basel, Switzerland, and the Tafelmusik Baroque Orchestra in Toronto. Drawing from her many firsthand experiences and zest for life, Ms. Payette will share an astronaut's high level perspective on extraordinarily complex, yet highly collaborative, challenges in space - from both a research and international diplomacy policy point of view.

The world's most ambitious scientific experiment is buried 100 meters underground, straddling Switzerland and France. A billion times every minute, the Large Hadron Collider (LHC) slams together protons, while four giant detectors watch closely. - So how does the Large Hadron Collider work? - Why can slamming tiny particles into each other provide clues about the nature of all space and time? - What mysteries are physicists trying to solve with data from the LHC? - How does the cutting edge of particle physics relate to the world around us, from the patterns of stars in the sky to the fact that they shine at all? Natalia Toro, PI Faculty, works at the intersection of theories and hard data. She will explain how complex collision data from the LHC is being digested and examined right now, and how it may set the course for the science of the future.

Learn about the future of “3D Printers” – machines that will fabricate arbitrary-shaped parts, layer by layer. Dr. Lipson will share a history of these technologies and preview a future in which we continue to gain unprecedented control over physical matter. If humans distinguish themselves from their evolutionary ancestors by making tools, then how might the ultimate tools – involving additive manufacturing – impact human culture forever? Dr. Lipson explores the science, technology and potential of programmable matter.