  Combining two entanglement-breaking channels into a correlated-noise
environment restores the distribution of entanglement. Surprisingly, this
reactivation can be induced by the injection of separable correlations from the
composite environment. In any dimension (finite or infinite), we can construct
classically-correlated "twirling" environments which are entanglement-breaking
in the transmission of single systems but entanglement-preserving when two
systems are transmitted. Here entanglement is simply preserved by the existence
of decoherence-free subspaces. Remarkably, even when such subspaces do not
exist, a fraction of the input entanglement can still be distributed. This is
found in separable Gaussian environments, where distillable entanglement is
able to survive the two-mode transmission, despite being broken in any
single-mode transmission by the strong thermal noise. In the Gaussian setting,
entanglement restoration is a threshold process, occurring only after a
critical amount of correlations has been injected. Such findings suggest new
perspectives for distributing entanglement in realistic environments with
extreme decoherence, identifying separable correlations and classical memory
effects as physical resources for "breaking entanglement-breaking".
