1:30 pm VIA ZOOM

Obstructions to Gapped Boundaries from Three-Manifold Invariants, Shu-Heng Shao, IAS

We derive new obstructions to a 2+1d bosonic TQFT (such as the Chern-Simons theory) admitting a gapped boundary. Each such obstruction is labeled by a closed three-manifold, and it arises as the phase of the Reshetikhin–Turaev invariant. Using these new obstructions and earlier results on this subject, we prove the following.

(1) An abelian bosonic TQFT admits a gapped boundary iff a finite list of certain "higher central charges" vanish.

(2) No power of the Fibonacci anyon (a.k.a. the (G2)_1 Chern-Simons theory) admits a gapped boundary.

This talk will be based on work in progress with J. Kaidi, Z. Komargodski, K. Ohmori, S. Seifnashri.

## Event Type

**May**

**3**