  Given a braided fusion category $C$, it is well known that the natural map $C
\boxtimes C^{bop} \to Z(C)$ from the square of $C$ to the (Drinfeld)
categorical center $Z(C)$ is an equivalence if and only if $C$ is modular.
However, it is not clear how to construct the inverse and the natural
isomorphisms. In this work, we provide an explicit construction using insights
from a specific quantum field theory, and explore how the equivalence fails for
the degenerate cases.
