  Understanding the collective behavior of strongly correlated electrons in
materials remains a central problem in many-particle quantum physics. A minimal
description of these systems is provided by the disordered Fermi-Hubbard model
(DFHM), which incorporates the interplay of motion in a disordered lattice with
local inter-particle interactions. Despite its minimal elements, many dynamical
properties of the DFHM are not well understood, owing to the complexity of
systems combining out-of-equilibrium behavior, interactions, and disorder in
higher spatial dimensions. Here, we study the relaxation dynamics of doubly
occupied lattice sites in the three-dimensional (3D) DFHM using
interaction-quench measurements on a quantum simulator composed of fermionic
atoms confined in an optical lattice. In addition to observing the widely
studied effect of disorder inhibiting relaxation, we find that the cooperation
between strong interactions and disorder also leads to the emergence of a
dynamical regime characterized by \textit{disorder-enhanced} relaxation. To
support these results, we develop an approximate numerical method and a
phenomenological model that each capture the essential physics of the decay
dynamics. Our results provide a theoretical framework for a previously
inaccessible regime of the DFHM and demonstrate the ability of quantum
simulators to enable understanding of complex many-body systems through minimal
models.
