Quantum communication using a nonlocal Zeno effect

It is shown that with the use of entanglement a specific two-party communic ation task can be done with a systematically smaller expected error than an y possible classical protocol could do. The example utilizes the very tight correlation between separate spin measurements on a singlet state for smal l differences in the angles of these two measurements. An extension of this example to many parties arranged in a row with only local, one-to-one comm unication (quantum whispering) is then considered. It is argued that in thi s scenario there exists no reliable classical protocol, whereas in the quan tum case there does. [S1050-2947(99)09303-8].