  The distribution of entangled quantum systems among two or more nodes of a
network is a key task at the basis of quantum communication, quantum
computation and quantum cryptography. Unfortunately the transmission lines used
in this procedure can introduce so much perturbations and noise in the
transmitted signal that prevent the possibility of restoring quantum
correlations in the received messages either by means of encoding optimization
or by exploiting local operations and classical communication. In this work we
present a procedure which allows one to improve the performance of some of
these channels. The mechanism underpinning this result is a protocol which we
dub cut-and-paste, as it consists in extracting and reshuffling the
sub-components of these communication lines, which finally succeed in
"correcting each other". The proof of this counterin- tuitive phenomenon, while
improving our theoretical understanding of quantum entanglement, has also a
direct application in the realization of quantum information networks based on
imperfect and highly noisy communication lines. A quantum optics experiment,
based on the transmission of single-photon polarization states, is also
presented which provides a proof-of-principle test of the proposed protocol.
