In quantum teleportation the quantum state of an object held by "Alice" is
instantaneously sent to "Bob". The technique works by sending one half of an
"entangled" light beam to Alice and the other to Bob. Alice measures the interaction
of this beam with the beam she wants to teleport. She sends that information to Bob
who uses it make an identical copy of the beam that Alice wanted to teleport. This
original beam is lost in the progress. In the experiment - performed by physicists from CalTech in the US,
Aarhus University
in Denmark and the University of Wales in Bangor - Alice used a 50/50 beam-splitter
to combine the output of a titanium sapphire laser with her half of the entangled beam
from an optical parametric oscillator. Alice then measured both outputs from the
beam-splitter and transmitted the results to Bob. Bob was then able to use this
information and his half of the entangled beam to create an exact copy of Alice's
original beam. Previously only two-state quantum systems - such as the polarization of a photon - had
been teleported. This new research should allow all quantum states to be teleported.
"[This could] allow quantum systems to perform information-processing tasks that
would be impossible in a classical world,
" according to Carlton Caves from the
University of New Mexico.
Quantum teleportation goes beyond two states
Oct 23, 1998
An international team of researchers from the US, Denmark and the UK has successfully "teleported" the quantum state of a whole beam of light (Science 282 706). Previously only individual photons have been teleported.









