Implications of Teleportation for Nonlocality

Jonathan Barrett

Published 2001-03-18, updated 2002-02-08Version 2

Adopting an approach similar to that of Zukowski [Phys. Rev. A 62, 032101 (2000)], we investigate connections between teleportation and nonlocality. We derive a Bell-type inequality pertaining to the teleportation scenario and show that it is violated in the case of teleportation using a perfect singlet. We also investigate teleportation using `Werner states' of the form x P + (1-x) I/4, where P is the projector corresponding to a singlet state and I is the identity. We find that our inequality is violated, implying nonlocality, if x > 1/sqrt(2). In addition, we extend Werner's local hidden variable model to simulation of teleportation with the x = 1/2 Werner state. Thus teleportation using this state does not involve nonlocality even though the fidelity achieved is 3/4 which is greater than the `classical limit' of 2/3. Finally, we comment on a result of Gisin's and offer some philosophical remarks on teleportation and nonlocality generally.