  The study of open quantum systems is important for fundamental issues of
quantum physics as well as for technological applications such as quantum
information processing. Recent developments in this field have increased our
basic understanding on how non-Markovian effects influence the dynamics of an
open quantum system, paving the way to exploit memory effects for various
quantum control tasks. Most often, the environment of an open system is thought
to act as a sink for the system information. However, here we demonstrate
experimentally that a photonic open system can exploit the information
initially held by its environment. Correlations in the environmental degrees of
freedom induce nonlocal memory effects where the bipartite open system
displays, counterintuitively, local Markovian and global non-Markovian
character. Our results also provide novel methods to protect and distribute
entanglement, and to experimentally quantify correlations in photonic
environments.
