  We study high-temperature magnetization transport in a many-body spin-1/2
chain with on-site quasiperiodic potential governed by the Fibonacci rule. In
the absence of interactions it is known that the system is critical with the
transport described by a continuously varying dynamical exponent (from
ballistic to localized) as a function of the on-site potential strength. Upon
introducing weak interactions, we find that an anomalous noninteracting
dynamical exponent becomes diffusive for any potential strength. This is borne
out by a boundary-driven Lindblad dynamics as well as unitary dynamics, with
agreeing diffusion constants. This must be contrasted to random potential where
transport is subdiffusive at such small interactions. Mean-field treatment of
the dynamics for small U always slows down the non-interacting dynamics to
subdiffusion, and is therefore unable to describe diffusion in an interacting
quasiperiodic system. Finally, briefly exploring larger interactions we find a
regime of interaction-induced subdiffusive dynamics, despite the on-site
potential itself having no "rare-regions".
