Teleportation Breakthrough Made:BBC

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Teleportation Breakthrough Made

By Paul Rincon

Science Staff |

BBC News Online

6-18-4

 

Scientists have performed successful teleportation on atoms for the

first time, the journal Nature reports. The feat was achieved by two

teams of researchers working independently on the problem in the US

and Austria.

 

The ability to transfer key properties of one particle to another

without using any physical link has until now only been achieved

with laser light.

 

Experts say being able to do the same with massive particles like

atoms could lead to new superfast computers.

 

This development is a long way from the transporters used by Jean-

Luc Picard and Captain Kirk in the famous Star Trek TV series.

 

When physicists talk about "teleportation", they are describing the

transfer of "quantum states" between separate atoms.

 

These would be such things as an atom's energy, motion, magnetic

field and other physical properties.

 

And in the computers of tomorrow, this information would form the

qubits (the quantum form of the digital bits 1 and 0) of data

processing through the machines.

 

 

Atomic dance

 

What the teams at the University of Innsbruck and the US National

Institute of Standards and Technology (Nist) did was teleport qubits

from one atom to another with the help of a third auxiliary atom.

 

It relies on a strange behaviour that exists at the atomic scale

known as "entanglement", whereby two particles can have related

properties even when they are far apart. Einstein called it

a "spooky action".

 

The two groups used different techniques for achieving

teleportation, but both followed the same basic protocol.

 

First, a pair of highly entangled, charged atoms (or ions) are

created: B and C. Next, the state to be teleported is created in a

third ion, A.

 

Then, one ion from the pair - let's say B - is entangled with A, and

the internal state of both is measured.

 

Finally, the quantum state of ion A is sent to ion C, transforming

it. This destroys the original quantum state of A.

 

The teleportation took place in milliseconds and at the push of a

button, the first time such a deterministic mechanism has been

developed for the process.

 

'Great potential'

 

The landmark experiments are being viewed as a major advance in the

quest to achieve ultra-fast computers, inside which teleportation

could provide a form of invisible "quantum wiring".

 

These machines would be able to handle far bigger and more complex

loads than today's super-computers, and at many times their speed.

 

"In a quantum computer it's straightforward enough to move quantum

information around by simply moving the qubits, but you might want

to do things very quickly, so you could use teleportation instead,"

said Nist's Dr David Wineland.

 

Professor Rainer Blatt, of the University of Innsbruck, told BBC

News Online: "This is a milestone.

 

 

"We are able to teleport in a deliberate way - that is, at the push

of a button. This has been done before, but not in such a way that

you can keep the information there at the end."

 

Professor Blatt's team, an Austrian-US group, performed the

teleportation on calcium ions. The Nist team in Boulder, Colorado,

used ions of the element beryllium.

 

Despite this and some differences in the experimental methods used

by the two groups, both teams reached similar values of fidelity -

around 0.75.

 

Fidelity is a measure of how well the quantum state of the second

ion after teleportation resembles the original quantum state.

 

Commenting in an article published in Nature, physicists H Jeff

Kimble and Steven Van Enk said: "These two experiments represent a

magnificent confluence of experimental advances, ranging from

precision spectroscopy and laser cooling.

 

"The fact that such diverse procedures performed so superbly in two

separate laboratories attests to the flexibility and great potential

of ion trapping for processing quantum information."

 

Step 1: A pair of entangled ions are created: B and C Step 2: The

state to be teleported is created in ion A

 

Step 3: One ion from the pair - in this case B - is entangled with A

and both are measured Step 4: The quantum state of A is sent to ion

C Step 5: The state created for A is teleported to C

 

© BBC MMIV http://news.bbc.co.uk/2/hi/science/nature/3811785.stm