Abstract

Motivated by predictions about the Anderson transition, we study two distinct but related models on regular tree graphs: The vertex-reinforced jump process (VRJP), a random walk preferring to jump to previously visited sites, and the H^{2|2}-model, a lattice spin system whose spins take values in a supersymmetric extension of the hyperbolic plane. Both models undergo a phase transition, and our work provides detailed information about the supercritical phase up to the critical point: We show that their order parameter has an essential singularity as one approaches the critical point, in contrast to algebraic divergences typically expected for statistical mechanics models. Moreover, we identify a previously unexpected multifractal intermediate regime in the supercritical phase. This talk is based on arxiv:2309.01221 and is joint work with Remy Poudevigne.