Going by such reports,* it appears that quantum computing is for real
and not merely a theoretical construct.



Dr D.C.Misra

September 11, 2007



*Einstein's `spooky' quantum computing, now for real



US physicists have coaxed two separate atoms to communicate with a sort
of quantum intuition that Albert Einstein (above) called "spooky." In
doing so, they have made an advance toward super-fast quantum computing



PHYSICISTS AT the University of Michigan have made an advance toward
super-fast quantum computing, which could also pave the way for making
quantum Internet
<http://epaper.hindustantimes.com/ArticleText.aspx?article=11_09_2007_01\
6_012&kword=&mode=1> a reality .

The scientists coaxed two separate atoms to communicate with a sort of
quantum intuition that Albert Einstein had called "spooky".

They used light to establish what's called "entanglement" between two
atoms, which were trapped a metre apart in separate enclosures.

"This linkage between remote atoms could be the fundamental piece of a
radically new quantum computer architecture
<http://epaper.hindustantimes.com/ArticleText.aspx?article=11_09_2007_01\
6_012&kword=&mode=1> ," said Professor Christopher Monroe, the principal
investigator who did this research while at UM, but is now at the
University of Maryland.

"Now that the technique has been demonstrated, it should be possible to
scale it up to networks
<http://epaper.hindustantimes.com/ArticleText.aspx?article=11_09_2007_01\
6_012&kword=&mode=1> of many interconnected components that will
eventually be necessary for quantum information processing," he said.

The lead author of the paper, David Moehring, now at the
Max-Planck-Institute for Quantum Optics in Germany, said the most
important feature of the experiment was the distance between the two
atoms.

"The separation of the qubits in our entangled state is the most
important feature. Localised entanglement has been performed in ion trap
qubits in the past, but if one desires to build a scalable quantum
computer network
<http://epaper.hindustantimes.com/ArticleText.aspx?article=11_09_2007_01\
6_012&kword=&mode=1> (or a quantum Internet), the creation of
entanglement schemes between remotely entangled qubit memories is
necessary," said Moehring.

In the experiment, the researchers used two atoms to function as qubits,
or quantum bits, storing a piece of information in their electron
configuration.

They then excited each atom, inducing electrons to fall into a lower
energy state and emit one photon, or one particle of light, in the
process.

The atoms, which were actually ions of the rare-earth element ytterbium,
are capable of emitting two different types of photon of different
wavelengths.

The type of photon released by each atom indicates the particular state
of the atom.

Because of this, each photon was entangled with its atom.

By manipulating the photons emitted from each of the two atoms and
guiding them to interact along a fibre optic
<http://epaper.hindustantimes.com/ArticleText.aspx?article=11_09_2007_01\
6_012&kword=&mode=1> thread, the researchers were able to detect the
resulting photon clicks and entangle the atoms.

A paper on the findings appears the journal Nature

(Source: The Hindustan Times, New Delhi, September 11, 2007, Tuesday,
p-16,
http://epaper.hindustantimes.com/ArticleText.aspx?article=11_09_2007_016\
_012&kword=&mode=1, accessed: September 11, 2007)







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