Colloquia

Quantum mechanical objects can exhibit correlations with one another that are fundamentally at odds with the paradigm of classical physics; one says that the objects are "entangled." In the past few years, entanglement has come to be studied not only as a marvel of nature but also as a potential resource, particularly as a resource for certain unusual kinds of communication. This talk reviews three proposed communication schemes based on entanglement: (i) dense coding, which is the effective doubling of the information-carrying capacity of a quantum particle through prior entanglement with a particle at the receiving end; (ii) teleportation, in which a quantum state is transferred from one particle to another over a distance, apparently without traversing the intervening space; and (iii) the efficient pooling of classical data, in which separated participants arrive at a conclusion faster because they share entanglement. These three schemes highlight three distinct ways in which entanglement can enhance communication.