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Math-Physics Joint Seminar

Wednesday, April 4, 2018 - 2:00pm

Nima Arkani-Hamed



University of Pennsylvania

DRL 4C2 (and 4C4)

Joint with the Deformation theory seminar. Please note the unusual time. The talk will be 2-3pm in 4C2, followed by discussion 3-5pm in 4C4.

Spacetime and Quantum Mechanics form the pillars of our understanding of modern physics, but there are several indications that these concepts are approximate and must emerge from deeper principles, undoubtedly involving new mathematics.

In this talk I will describe some emerging ideas along these lines, and present a new formulation of some very basic physics-- fundamental to particle scattering and to cosmology--not following from quantum evolution in space-time, but associated with simple new mathematical structures in "positive geometry". The simplest examples of positive geometries are polytopes old and new, from cyclic polytopes and Associahedra to ``cosmological" polytopes. Others, such as the``Amplituhedron", involve generalizations of polytopes into the Grassmannian. In these examples we can concretely see how the usual rules of space-time and quantum mechanics can arise, joined at the hip, from fundamentally geometric and combinatorial origins.

Video: Spacetime, Quantum Mechanics and Positive Geometry, part 1
Video: Spacetime, Quantum Mechanics and Positive Geometry, part 2