Teleportation
method proposed by Australian scientists
Teleportation,
a concept popularised in the original Star Trek television series, is edging closer
to reality through work being conducted by theorists from The University of Queensland
and Australian National University.
Researchers from UQ's Australian
Research Centre for Quantum Atom Optics (Dr Ashton Bradley, Dr Simon Haine and
Dr Murray Olsen) and Australian National University (Joseph Hope) have proposed
a new way of teleporting matter waves.
“We
propose a scheme which allows an atom laser beam to disappear at one location
and reappear at another,” Dr Bradley said.
“We
feel that our scheme is closer in spirit to the original fictional concept,”
Dr Haine said.
“What
differentiates our scheme from what is usually termed quantum teleportation is
that our scheme does not require the sender and receiver to share entangled states,
as there is no measurement step involved in sending the information.
"In
this scheme the sender and receiver require a reservoir of extremely cold atoms,
known as a Bose-Einstein condensate (BEC).
"BEC
is a state of matter that occurs when atoms become very cold, (about 100 billionths
of a degree about absolute zero).
"Due
to a phenomenon known as Bose-Enhancement, all the atoms like to act the same
way. This causes the atoms to act as one macroscopic matterwave, rather than a
collection of individual atoms.”
Dr
Haine said that sending a pulse of atoms towards a trapped condensate (BEC) and
illuminating them with a control laser beam, the atoms from the pulse were stimulated
to act the same way as the atoms already trapped in the BEC.
This
resulted in the emission of a photon. As all the atoms in the BEC had a very well-defined
momentum, the photons being emitted would follow the same direction and form a
signal beam.
"We
can arrange the position and momentum of each atom (quantum information) to be
encoded onto the signal beam by carefully adjusting the intensity and wavelength
of the control beam,” Dr Haine said.
The
signal beam is then sent to a second BEC, which is also illuminated with a control
laser. The atoms trapped in the BEC absorb the photon from the signal beam, and
in turn are forced to emit the photon into the control beam.
Due
to the momentum of releasing the photons, the atoms are kicked out of the BEC.
These atoms contain the quantum information of the original atomic pulse which
has been transferred to the new pulse, effectively teleporting the original pulse
of atoms.
"Our
scheme is quite different from what is usually coined quantum teleportation because
it gets around the need for the sender and receiver to share entanglement, as
the quantum state to be teleported is never actually measured," Dr Bradley
said.
"As
our scheme doesn't rely on the quality of the entanglement, it may be possible
to achieve more accurate teleportation via this method," he said.
Dr
Bradley said the team would now embark on more detailed calculations, which took
into account more complicated effects including the effects of the atoms colliding
with each other, which could degrade the fidelity of the teleportation.
Dr
John Close at ANU also has plans to implement these experiments and related ones
in the next few years.
Links:
Original paper -- http://arxiv.org/abs/0706.0062 ;
http://www.acqao.org/news/readMore_TeleportationofMassiveParticles.html
