G-equivariant Alterfold TQFT in any dimension

Abstract

For a discrete group $G$, we construct an $(n+1)$-dimensional $G$-equivariant Alterfold topological quantum field theory from a $G$-equivariant $S^n$-algebra satisfying strong semisimplicity, complete finiteness, and Morita invariance. We use state sum on triangulation to define a partition function and prove that it is invariant under local surgery relations and is invariant under gauge transformations relative to the boundary. If the input is given a reflection-positive structure, the theory is unitary. For $n=2$ and input reconstructed from a strict faithful spherical $G$-fusion category, the restriction to ordinary $G$-cobordisms is naturally isomorphic to the Turaev--Virelizier state-sum HQFT \cite{turaev20123}. A Tambara-Yamagami example recovers the Quon language \cite{liu2017quon} as a $\mathbb{Z}_2$-equivariant Alterfold TQFT.