# Event detail

## Representation Theory and Mathematical Physics Seminar: Higher categories, generalized cohomology, and condensed matter.

Seminar | November 15 | 4-5 p.m. | 939 Evans Hall

Theo Johnson-Freyd, Perimeter Institute

I will report on joint work in progress with Davide Gaiotto on the classification of gapped phases of matter. I will explain what symmetry protected phases are and why they are classified by reduced generalized group cohomology. I will also introduce the notion of "condensable n-algebra," and the higher category thereof, as an axiomatization of the algebraic structure enjoyed by gapped phases that can be condensed from the vacuum. Finally, I will interpret the Cobordism Hypothesis as the equivalence between (condensable) topological field theories and (condensable) gapped phases.