Theos-Talk Archives (June 2004 Message tt00098)

June 17th 2004

 

Dear Lenny:

 

 

Any good comments on this ?

 

Thanks,

 

Dallas

 

=============================

 

-----Original Message-----
From: jef 
Sent: Thursday, June 17, 2004 9:09 AM
To: Dallas TenBroeck
Subject: New York Times: Science

 


June 17, 2004

Scientists Teleport Not Kirk, but an Atom
By KENNETH CHANG
 

And the beryllium atom said to the Starship Enterprise, beam me up!

Two teams of scientists report today that for the first time they have
teleported individual atoms, taking characteristics of one atom and
imprinting them on a second.

In physics, teleportation means creating a replica of an object, or
at least some aspect of it, at some distance from the original. The
act of teleporting always destroys the original - not entirely unlike
the transporters of the "Star Trek" television shows and movies - so
it is impossible produce multiple copies.

The prospect of using teleportation to move large objects or people
remains far beyond the current realm of possibility. But it could
prove an important component of so-called quantum computers.
Scientists hope that one day such computers will tap quantum mechanics
to solve complex problems quickly by calculating many different
possible answers at once; computers today must calculate each
possibility separately.

The two teams, one at the National Institute of Standards and
Technology in Boulder, Colo., and one at the University of Innsbruck
in Austria, worked independently, but the experiments were similar,
using a process proposed by Dr. Charles H. Bennett, a scientist at
I.B.M., and others in 1993.

"This will be an important part of attempts to build quantum
computers," said Dr. H. Jeff Kimble, a professor of physics at the
California Institute of Technology. He co-wrote a commentary
accompanying the two research papers on the experiments, which appear
today in the journal Nature.

"This is a complicated thing that begins to work," Dr. Kimble said.
"We've reached this point on our journey and it's really quite
significant."

Several scientific groups, including one led by Dr. Kimble, previously
teleported photons, and scientists at the University of Aarhus in
Denmark reported in 2001 that they had teleported the magnetic field
produced by clouds of atoms.

In the new experiments, both teams of scientists worked with triplets
of charged atoms trapped in magnetic fields. The Colorado team used
beryllium; the Innsbruck researchers used calcium.

The feat of teleportation is transferring information from atom A to
atom C without the two meeting. The third atom, B, is an intermediary.

The three atoms can be thought of as boxes that can contain a 1 or a
zero, a bit of information like that used by a conventional computer
chip. The promise of quantum computers is that both a zero and a 1 can
exist at once, just like the perplexing premise described by the
Austrian physicist Erwin Schrödinger in which a cat in a box can be
simultaneously alive and dead until someone looks inside.

First, atoms B and C were brought together, making them "entangled"
and creating an invisible link between the two atoms no matter how far
apart they were. Atom C was moved away. Next, A and B were similarly
entangled.

Then the scientists measured the energy states of A and B, essentially
opening the boxes to see whether each contained a 1 or a zero. Because
B had been entangled with C, opening A and B created an instant change
in atom C, what Albert Einstein called "spooky action at a distance,"
and this, in essence, set a combination lock on atom C, with the data
in A and B serving as the combination.

For the final step, the combination was sent and a pulse of laser
light was applied to atom C, almost magically turning it into a
replica of the original A. Atom A was teleported to atom C.

"It's a way of transferring the information," Dr. Rainer Blatt, leader
of the Innsbruck team, said.

A quantum computer could use teleportation to move the results of
calculations from one part of the computer to another. "Teleportation
in principle could be done pretty quick," said Dr. David J. Wineland,
head of the Colorado team, noting that directly moving atoms
containing intermediate results would almost certainly be too slow.

In the current experiments, the teleportation distances were a
fraction of a millimeter, but in principle, the atoms could be
teleported over much longer distances. The teleportation was also not
perfect, succeeding about three-quarters of the time.

"We're not doing very well yet," Dr. Wineland said. "All of these
operations have to be improved."

Teleporting a much larger object, like a person, appears unlikely, if
not entirely impossible, because too much information would have to be
captured and transmitted.

"It's certainly not useful for any beaming in the 'Star Trek' sense,"
Dr. Blatt of the University of Innsbruck said. "Consider even some
molecules or something small like a virus. I cannot imagine it. As far
as I can see, it's not going to happen."



 


Copyright 2004 The New York Times Company |
Sent using the Microsoft Entourage 2004 for Mac Test Drive.



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