Large orders and strong-coupling limit in functional renormalization

We study the large-order behavior of the functional renormalization group (FRG). For a model in dimension zero, we establish Borel summability for a large class of microscopic couplings. Writing the derivatives of FRG as contour integrals, we express the Borel transform as well as the original series as integrals. Taking the strong-coupling limit in this representation, we show that all short-ranged microscopic disorders flow to the same universal fixed point. Our results are relevant for FRG in disordered elastic systems.