Entropy of cluster DT transformations and the finite-tame-wild trichotomy of acyclic quivers

Abstract: The cluster algebra associated with an acyclic quiver has a special mutation loop $\tau$, called the cluster Donaldson--Thomas (DT) transformation, related to the Auslander--Reiten translation. In this paper, we characterize the finite-tame-wild trichotomy for acyclic quivers by the sign stability of $\tau$ introduced in [IK21] and its cluster stretch factor. As an application, we compute several kinds of entropies of $\tau$ and other mutation loops. In particular, we show that the algebraic and categorical entropies of $\tau$ are commonly given by the logarithm of the spectral radius of the Coxeter matrix associated with the quiver, and that any mutation loop of finite or tame acyclic quivers have zero algebraic entropy.