The Reidemeister torsion may be viewed as a volume form on the character variety of a 3-manifold with boundary. I will explain a conjectural differential equation that this form should satisfy, motivated by the study of the asymptotical behaviour of quantum invariants.

The Fibonacci TQFT gives interesting representations of mapping class groups into pseudo-unitary groups. In some exceptional cases, they correspond to holonomy representation of complex hyperbolic structures on some compactifications of the moduli spaces of curves. The proof uses a computation of the Toledo invariant which fits in the framework of Cohomological Field theories. This is joint work with Bertrand Deroin.