Contributor info: Dr Theo Johnson-Freyd

Theo Johnson-Freyd, Matthew Yu

SciPost Phys. 13, 068 (2022) · published 27 September 2022 | Toggle abstract · pdf

We investigate the Morita equivalences of (4+1)-dimensional topological orders. We show that any (4+1)-dimensional super (fermionic) topological order admits a gapped boundary condition -- in other words, all (4+1)-dimensional super topological orders are Morita trivial. As a result, there are no inherently gapless super (3+1)-dimensional theories. On the other hand, we show that there are infinitely many algebraically Morita-inequivalent bosonic (4+1)-dimensional topological orders.