  No quantum system can be considered totally isolated from its environment. In
most cases the interaction between the system of interest and the external
degrees of freedom deeply changes its dynamics, as described by open quantum
system theory. Nevertheless, engineered environment can be turned into
beneficial effects for some quantum information tasks. Here we demonstrate an
optical simulator of a quantum system coupled to an arbitrary and
reconfigurable environment built as a complex network of quantum interacting
systems. We experimentally retrieve typical features of open quantum system
dynamics like the spectral density and quantum non-Markovianity, by exploiting
squeezing and entanglement correlation of a continuous variables optical
platform. This opens the way to the experimental tests of open quantum systems
in reconfigurable environments that are relevant in, among others, quantum
information, quantum thermodynamics, quantum transport and quantum
synchronization.
