Quantum remote control: Teleportation of unitary operations - art. no. 042303

We consider the implementation of an arbitrary unitary operation U upon a d istant quantum system. This teleportation of U can be viewed as quantum rem ote control. We investigate protocols that achieve this using local operati ons, classical communication, and shared entanglement. Lower bounds on the necessary entanglement and classical communication are determined using cau sality and the linearity of quantum mechanics. We examine in particular det ail the resources required if the remote control is to be implemented as a classical black box. Under these circumstances, we prove that the required resources are, necessarily, those needed for implementation by bidirectiona l state teleportation.