9 v 1 2 9 O ct 1 99 8 Teleportation : Dream or Reality ?

Since its discovery in 1993, we witness an intensive theoretical and experimental effort centered on teleportation. Very recently it was claimed in the press that " quantum teleportation has been achieved in the laboratory " (T. Sudbery, Nature 390, 551). Here, I briefly review this research focusing on the connection to nonlo-cal measurements, and question Sudbery's statement. A philosophical inquiry about the paradoxical meaning of teleportation in the framework of the many-worlds interpretation is added. 1 The meaning of the Word " Teleportation " Let me start with a citation from the Oxford English Dictionary [1]: teleportation. Psychics and Science Fiction. The conveyance of persons (esp. of oneself) or things by psychic power; also in futuristic description, apparently instantaneous transportation of persons, etc., across space by advanced technological means. Recently, the word " teleportation " has appeared outside of the realm of mystical and science fiction literature: in science journals. and Wootters (BBCJPW) [6] proposed a gedanken experiment they termed " quantum teleportation ". Classically, to move a person is to move all the particles it is made of. However, in quantum theory particles themselves do not represent a person: all objects are made of the same elementary particles. An electron in my body is identical to an electron in the paper of the page you are reading now. An object is characterized by the quantum state of the particles it is made of. Thus, reconstructing the quantum state of these particles on other particles of the same kind at a remote location is " transportation " of the object.