Entanglement as a Resource

As we have seen in Chapter 4, multi-qubit systems can exist in correlated

states known as entangled states. In computing algorithms, entanglement is

implicit, but nowhere is it more dramatically useful than in protocols for com-

munication, where quantum correlations are exploited for security of commu-

nication as well as for coding efficiency. This quantum correlation shared by

spatially separated parties is used as a communication resource. The term

ebit has been coined to quantify this resource. An ebit can be thought of as

the amount of entanglement in a Bell state.

Information and Communication 179

FIGURE 9.2: Quantum Teleportation