  Optically-generated nonequilibrium phonon-distribution is used for exploring
the origin of a nonlocal adiabatic response in an interacting Anderson
insulator. Exposing the system to weak infrared radiation is shown to
effectively suppress a long-range effect observed in field-effect experiments
while producing little heating and barely changing the system conductance.
These effects are shown to be consistent with the quantum nature of the effect
and therefore are peculiar to disordered systems that are quantum-coherent.
