But what if there were a way to get you from your home to the supermarket
without having to use your car or from your backyard to the International
Space Station without having to board a spacecraft? There are scientists
working right now on such a method of travel, combining properties of
telecommunications and transportation to achieve a system called teleportation.
In this article, you will learn about experiments that have actually
achieved teleportation with photonsand how we might be able to use teleportation
to travel anywhere, at anytime.
What is Teleportation?
Teleportation involves de-materializing an object at
one point, and sending the details of that object's precise atomic configuration
to another location, where it will be reconstructed. What this means
is that time and space could be eliminated from travel we could be transported
to any location instantly, without actually crossing a physical distance.
Most of us were introduced to the idea of teleportation,
and other futuristic technologies, by the short-lived Star Trek television
series (1966-69) based on tales written by Gene Roddenberry. Viewers
watched in amazement as Captain Kirk, Spock, Dr. McCoy and others beamed
down to the planets they encountered on their journeys through the universe.
In 1993, the idea of teleportation moved out of the
realm of science fiction and into the world of theoretical possibility.
It was then that physicist Charles Bennett and a team of researchers
at IBM confirmed that quantum teleportation was possible, but only if
the original object being teleported was destroyed. This revelation,
first announced by Bennett at an annual meeting of the American Physical
Society in March 1993, was followed by a report on his findings in March
29, 1993 issue of Physical Review Letters Since that time, experiments
using photons have proven that quantum teleportation is in fact possible.
Photon Experiments
In 1998, physicists at the California Institute of
Technology (Caltech), along with two European groups, turned the IBM
ideas into reality by successfully teleporting a photon, a particle
of energy that carries light. The Caltech group was able to read the
atomic structure of photon, send this information across 1 meter (3.28
feet) of coaxial cable and create a replica of the photon. As predicted,
the original photon no longer existed once the replica was made. In
performing the experiment, the Caltech group was able to get around
the Heisenberg Uncertainty Principle, the main barrier for teleportation
of objects larger than a photon. This principle states that you cannot
simultaneously know the location and the speed of a particle. But if
you can't know the position of a particle, then how can you teleport
it? In order to teleport a photon without violating the Heisenberg Principle,
the Caltech physicists used a phenomenon known as entanglement
. In entanglement, at least three photons are needed to achieve quantum
teleportation:
Photon A: The photon to be teleported
Photon B: The transporting photon
Photon C: The photon that is entangled with photon B
If researchers tried to look too closely at photon A without entanglement,
they would bump it, and thereby change it. By entangling photons B and
C, researchers can extract some information about photon A, and the
remaining information would be passed on to B by way of entanglement,
and then on to photon C. When researchers apply the information from
photon A to photon C, they can create an exact replica of photon A.
However, photon A no longer exists as it did before the information
was sent to photon C.
In other words, when Captain Kirk beams down to an
alien planet, an analysis of his atomic structure is passed through
the transporter room to his desired location, where a replica of Kirk
is created and the original is destroyed.
A more recent teleportation success was achieved at
the AustralianNationalUniversity , when researchers successfully teleported
a laser beam While the idea of creating replicas of objects and destroying
the originals doesn't sound too inviting for humans, quantum teleportation
does hold promise for quantum computing. These experiments with photons
are important in developing networks that can distribute quantum information.
Professor Samuel Braunstein , of the University of Wales , Bangor ,
called such a network a "quantum Internet." This technology
may be used one day to build a quantum computer that has data transmission
rates many times faster than today's most powerful computers.
Quantum Teleportation
Teleportation is the name given by science fiction
writers to the feat of making an object or person disintegrate in one
place while a perfect replica appears somewhere else. How this is accomplished
is usually not explained in detail, but the general idea seems to be
that the original object is scanned in such a way as to extract all
the information from it, then this information is transmitted to the
receiving location and used to construct the replica, not necessarily
from the actual material of the original, but perhaps from atoms of
the same kinds, arranged in exactly the same pattern as the original.
A teleportation machine would be like a fax machine, except that it
would work on 3-dimensional objects as well as documents, it would produce
an exact copy rather than an approximate facsimile, and it would destroy
the original in the process of scanning it. A few science fiction writers
consider teleporters that preserve the original, and the plot gets complicated
when the original and teleported versions of the same person meet, but
the more common kind of teleporter destroys the original, functioning
as a super transportation device, not as a perfect replicator of souls
and bodies.
In 1993 an international group of six scientists, including
IBM Fellow Charles H. Bennett, confirmed the intuitions of the majority
of science fiction writers by showing that perfect teleportation is
indeed possible in principle, but only if the original is destroyed.
In subsequent years, other scientists have demonstrated teleportation
experimentally in a variety of systems, including single photons, coherent
light fields, nuclear spins, and trapped ions. Teleportation promises
to be quite useful as information processing primitive, facilitating
long-range quantum communication (perhaps ultimately leading to a "quantum
internet"), and making it much easier to build a working quantum
computer. But science fiction fans will be disappointed to learn that
no one expects to be able to teleport people or other macroscopic objects
in the foreseeable future, for a variety of engineering reasons, even
though it would not violate any fundamental law to do so.
In the past, scientists did not take the idea of teleportation
very seriously, because it was thought to violate the uncertainty principle
of quantum mechanics, which forbids any measuring or scanning process
from extracting all the information in an atom or other object. According
to the uncertainty principle, the more accurately an object is scanned,
the more it is disturbed by the scanning process, until one reaches
a point where the object's original state has been completely disrupted,
still without having extracted enough information to make a perfect
replica. This sounds like a solid argument against teleportation: if
one cannot extract enough information from an object to make a perfect
copy, it would seem that a perfect copy couldn't be made. But the six
scientists found a way to make an end run around this logic, using a
celebrated and paradoxical feature of quantum mechanics known as the
Einstein- Podolsky -Rosen effect. In brief, they found a way to scan
out part of the information from an object A, which one wishes to teleport,
while causing the remaining, unscanned , part of the information to
pass, via the Einstein- Podolsky -Rosen effect, into another object
C which has never been in contact with A. Later, by applying to C a
treatment depending on the scanned-out information, it is possible to
maneuver C into exactly the same state as A was in before it was scanned.
A itself is no longer in that state, having been thoroughly disrupted
by the scanning, so what has been achieved is teleportation, not replication.
Spy Networks And Financial
organizations are the beneficiaries:
Spy networks and international financial systems are
set to benefit from a significant advance in teleportation technology
developed at The Australian National University. ANU researchers in
Canberra have announced that they are the first in the world to demonstrate
the sharing of secrets via teleportation using quantum physics. The
research has potential to significantly enhance the security of computer
systems around the world.
The researchers provided a window on the future of
telecommunications by demonstrating the production, disembodiment and
successful reconstruction -- or teleportation -- of a message to a network
of participants. The experiment was conducted by 24-year-old PhD student
Andrew Lance and Dr Thomas Symul from the Quantum Optics Group in the
ANU Faculty of Science, in collaboration with Professor Barry Sanders
from the University of Calgary in Canada .
The research, published in the latest edition of Physical
Review Letters, is expected to attract attention from defence and finance
industries around the world. It builds on the teleportation work conducted
by Dr Warwick Bowen and Dr Ping Koy Lam at the ANU in 2002, when they
teleported information using a laser beam. "This is a much more
complex form of information teleportation in the sense that it involves
multiple recipients," Dr Lam said. Acting ANU Vice-Chancellor Professor
Lawrence Cram congratulated the team on their success.
The researchers used crystals, lenses and mirrors to
produce a pair of 'entangled' laser beams that are then used to carry
fragile information in the form of quantum states. These quantum states
cannot be measured or copied, making eavesdropping impossible. The transmission
of the light beams constitutes a secret communication scheme with guaranteed
security.
The process of secret sharing is a fundamental part
of present day telecommunication, computer and banking practices. Such
network communication can be enhanced using the laws of quantum physics
to protect the information -- a process called quantum state sharing.
"The benefit of this technology is that the encrypted message can
only be decoded by a majority of recipients. For example, if an encrypted
message was sent to a spy network containing 15 individuals, a minimum
of eight agents would be needed to access the message -- limiting the
chances of the message being infiltrated or deleted by a double-agent,"
Mr. Lance said. "The system could also have major applications
as a fail-safe mechanism in operating systems for the new generation
of super-fast quantum computers." Barry Sanders, iCORE Professor
and Director of the newly launched Institute for Quantum Information
Science at the University of Calgary , said; "Security is crucial
for quantum networks that may someday deliver ultra fast solutions to
certain computational problems and for communication that is impervious
to eavesdroppers. Our experiment demonstrates that quantum networks
can be protected from component failures and malice."
Then visualize or feel the object leaving your hands
in a word d
How To Sound Like An Expert
Everybody knows about teleportation. But many people's
knowledge is derived entirely from sci-fi books and movies, not from
any real science. You can often spot these individuals by their tendency
to refer to teleportation as something primarily done by humans (or
aliens), and done by them of their own volition, in the same way you
might decide to, say, stand up, or make a phone call. Physicists use
a somewhat different vocabulary when discussing teleportation (even
though many of them are active sci-fi fans when they're away from the
lab, so can speak both languages).
Where does the word "teleportation"
come from?
Zero points if your answer is The Twilight Zone. The
strictly accurate answer for people with large foreheads is that it
derives from two words: " telos " - from the Greek, meaning
"end" or "endpoint", and " portare " from
the Latin, meaning "to carry". So teleportation means, "to
carry to an endpoint"... So, there are many interpretations, but
the essential characteristic of teleportation though is that it is instantaneous
and has no regard for distance between origin and destination.
(Theo www.aptech-education.com) |