A chain of interacting spin behaves like a quantum mediator (quantum link), which allows two distant parties that control the ends of the chain to exchange quantum messages. We show that over repeated uses without resetting ...

We discuss an explicit protocol which allows one to externally cool and control a composite system by operating on a small subset of it. The scheme permits to transfer arbitrary and unknown quantum states from a memory on ...

In this addendum to our paper [ D. Burgarth and V. Giovannetti Phys. Rev. Lett. 99 100501 (2007)] we prove that during the transformation that allows one to enforce control by relaxation on a quantum system, the ancillary ...