A posteriori teleportation

Abstract

The article by Bouwmeester et al.¹ on experimental quantum teleportation constitutes an important advance in the burgeoning field of quantum information. The experiment was motivated by the proposal of Bennett et al.² in which an unknown quantum state is ‘teleported’ by Alice to Bob. As illustrated in Fig. 1, in the implementation of this procedure by Bouwmeester et al.¹, an input quantum state is ‘disembodied’ into quantum and classical components, as in the original protocol². However, in contrast to the original scheme, Bouwmeester et al.'s procedure necessarily destroys the state at Bob's receiving terminal, so a ‘teleported’ state can never emerge as a freely propagating state for subsequent examination or exploitation. In fact, teleportation is achieved only as a postdiction.