  In many applications entanglement must be distributed through noisy
communication channels that unavoidably degrade it. Entanglement cannot be
generated by local operations and classical communication (LOCC), implying that
once it has been distributed it is not possible to recreate it by LOCC.
Recovery of entanglement by purely local control is however not forbidden in
the presence of non-Markovian dynamics, and here we demonstrate in two
all-optical experiments that such entanglement restoration can even be achieved
on-demand. First, we implement an open-loop control scheme based on a purely
local operation, without acquiring any information on the environment; then, we
use a closed-loop scheme in which the environment is measured, the outcome
controling the local operations on the system. The restored entanglement is a
manifestation of "hidden" quantum correlations resumed by the local control.
Relying on local control, both schemes improve the efficiency of entanglement
sharing in distributed quantum networks.
