Space Forum / Astronomy / July 2004

Physics: "Putting The Weirdness To Work"  

Scientists say quantum materials will be the basis for
amazing devices, but when?

Science & Technology
Business Week
March 15, 2004

The world of the quantum stretches the limits of human
imagination. Who could ever believe, for instance, that
atoms -- the building blocks of our seemingly solid
landscape -- are able to exist in different places at one
time? That they can be "entangled" together such that an
action on one atom or particle will affect another across
considerable distances? Or that they are irrevocably
altered simply by the act of being observed?

Yet that is what quantum laws tell us. Einstein himself
was famously troubled by the implication that reality was
actually just a collection of probabilities, where God
not only played dice with the universe but also hid the
dice. "To common sense, quantum mechanics is
nonsensical," says Nobel prize-winning physicist William
D. Phillips of the National Institute of Standards &
Technology (NIST).

Nevertheless, developing quantum theory was "the crowning
intellectual achievement of the last century," says
California Institute of Technology physicist John
Preskill. It's the underlying principle for many of
today's devices, from lasers to magnetic resonance
imaging machines. And these may prove to be just the low-
hanging fruit. Many scientists foresee revolutionary
technologies based on the truly strange properties of the
quantum world.

For instance, there's a state of matter that scientists
created less than a decade ago called the Bose-Einstein
condensate, in which each of many millions of atoms act
identically and are everywhere in the sample at once.
Dozens of research groups around the world are
experimenting with these condensates, whose properties
portend a future we can barely glimpse. "Physicists
relish the weirdness, but now we're starting to ask if we
can put the weirdness to work," says Preskill.

Some of the theoretical possibilities boggle the mind.
For example: the elusive but intensely desired quantum
computer. The mathematical challenge of factoring a 400-
digit number -- which would take 10 billion years on
today's supercomputers -- might be cracked by a quantum
computer in 30 seconds. While there are a number of
approaches to building such a device, recent experiments
with the Bose-Einstein condensates are opening up clever
new paths.

Quantum weirdness also enables communications to be sent
in unbreakable code. New companies, such as New York
City's MagiQ Technologies and id Quantique of Geneva, are
already turning these ideas into commercial products. At
the same time, the exploration of quantum domains may
shed more light on abiding scientific mysteries, such as
how some substances conduct electricity with zero
resistance -- a phenomenon called superconductivity. That
could lead to the transmission of electricity across
great distances with no loss. And a forthcoming paper
from IBM researchers will show how quantum phenomena can
be exploited to see molecules more clearly.

These uses may just scratch the surface of the possible.
No one has ever been able to foresee transformations
wrought by any revolutionary science. And the quantum
world is no different. "We have not yet begun to figure
out what the applications are," says NIST physicist Carl
J. Williams. "But the risk is underestimating the
impact."

Quantum computers and most other applications are decades
away, if indeed they can be built at all. Still, the
enormous potential has led to programs at companies like
IBM (IBM ) and Hewlett-Packard Co. (HPQ ). The Pentagon's
Defense Advanced Research Projects Agency is now
beginning a major effort to construct a working quantum
information processor. In all these efforts, "the goal is
the control of quantum matter," says Immanuel Bloch of
the Johannes Gutenberg University of Mainz. "It's a great
challenge, but there are great rewards."

For a glimpse of this endeavor, drop by the lab of
William Phillips and his team in Gaithersburg, Md.
Sprawling over a giant lab bench is a maze of precision
mirrors and lasers, all converging on a small glass
vacuum chamber where the quantum world is being probed.
Phillips won his Nobel in 1997 for a technique known as
laser cooling, in which beams are used to slow atoms
down. That chills the atoms until they are a fraction of
a degree above absolute zero. Now, using rubidium atoms,
Phillips is making them even colder by letting the warmer
ones "evaporate."

PEAKS AND TROUGHS. Inside the glass chamber, he is
creating the fragile Bose-Einstein condensate. The clump
of atoms can be huge -- big enough to be visible to the
naked eye. At that scale, you would expect the stolid
laws of Newtonian physics to rule. Instead, the atoms
obey the Heisenberg uncertainty principle, which
specifies that an electron or atom can't be pinned down
to any one location. Even though the clump is a tenth of
a millimeter across and contains a million atoms, "every
atom is everywhere -- that's what makes it so wonderful,"
says Williams.

This strange state of matter was predicted by Einstein,
building on work by Indian physicist Satyendra Nath Bose,
back in 1924. It was first created by Phillips' NIST
colleague, Eric A. Cornell, and Carl E. Wieman of the
University of Colorado, in 1995 -- a Nobel prize-winning
achievement. Now, an estimated 50 groups around the world
are experimenting with the strange stuff. "It can do some
amazing things," says Phillips.

One of the most intriguing -- and potentially useful --
maneuvers in Phillips' lab involves putting the atoms
into neat little rows. The trick is using precisely tuned
laser light. Imagine dropping pebbles into a pond,
sending waves across the water. Then drop pebbles at the
opposite shore, dispatching waves in the other direction.
Where the two groups of waves meet, they create so-called
standing waves -- an unchanging collection of peaks and
troughs, like a row of sand dunes in the desert.

Laser light is also a wave. So two intersecting beams
similarly create peaks and valleys. Scientists call this
an optical lattice. And when Phillips and other
researchers shine intersecting laser beams though the
Bose-Einstein clump of atoms, individual atoms almost
magically go from being everywhere at once to nestling in
the valleys. "It's a great gift of nature," says
Phillips. "We've been lucky that things worked better
than expected."

To information scientists, such a neat arrangement of
atoms looks startlingly like the basis for a computer. It
can be arranged that each atom is in one of two energy
levels, separated by a small quantum jump. Thus, each
atom could represent a 0 or a 1, like the bits in a
regular computer.

But these are no ordinary bits. Because of quantum
weirdness, an atom can be a 0 and a 1 at the same time.
What's more, the different quantum bits, or "qubits," can
be entangled with each other, even if there is no actual
connection. "Because of the mystery of entanglement, the
state of one atom will be dependent on the state of the
other," explains Williams. "It's a much stronger
relationship than marriage." As a result, for some
calculations, the power of a quantum machine grows
exponentially with the number of qubits -- twice the bits
gives you four times the power. A 300-qubit machine could
store more combinations than there are atoms in the
entire universe, says Williams.

CLEVER ALTERNATIVES. Without doubt, there's a long, long
path to building such a machine, and today's researchers
have only begun the journey. Phillips and his team are
now working on the next small step. They're trying to
figure out how to get information to and from the
individual qubits, by flipping the atoms from one state
to the other with laser beams.

Meanwhile, other labs are pursuing clever alternatives.
At the University of Mainz, Bloch is also putting Bose-
Einstein condensate atoms into the valleys of an optical
lattice. His special twist is creating two simultaneous
lattices with two different "colors" of laser beams. He
also puts his atoms in two states at the same time. Then
he can move one of the landscapes so that the atom
particles interact in new ways. "We can entangle hundreds
of thousands of atoms and measure the state of each
particle," he says. "It is a completely new way of
thinking about a quantum computer."

Another tack is to use ions trapped in a magnetic field
as qubits, instead of atoms in the optical lattice. Out
in NIST's Boulder (Colo.) labs, David J. Wineland has
built working logic gates -- a building block of
computers -- using such ions. And many other groups are
experimenting with tiny bits of semiconductor material,
dubbed quantum dots.

The ultimate payoff, however, is expected to go far
beyond computing. Since the very act of observing quantum
information changes it, communications that are encrypted
with quantum "keys" could be sent safely across a
network. The reason: Any attempt by spies to intercept
the key would immediately be obvious, so users could
switch to a different one.

As exciting as these applications are, researchers are
also thrilled by the basic science. Earlier this year,
NIST physicist Deborah S. Jin created a state of matter
called a fermionic condensate that is even rarer than the
closely related Bose-Einstein materials. She managed to
put atoms that don't normally like being next to each
other into the same low-energy state. Her work could lead
to a better understanding of superconductivity, which
depends on similar pairs of quantum particles.

Scientists are often surprised by what they encounter.
Not long ago, Phillips was experimenting with faint laser
beams, which unexpectedly impeded the movements of atoms.
"We don't know if this is interesting new physics or some
stupid mistake," he says. "In learning about quantum
computing, we're at the forefront of fundamen- tal
physics." That's how science and technology sometimes
advance -- one small quantum step at a time.

By John Carey in Gaithersburg, Md.

http://www.businessweek.com:/print/magazine/content/04_11/b3874102.htm?tc

Posted by billorites

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Oh.

View picture here:

http://209.237.0.15/~jkahn/temp/friendforlife.jpg

I was afraid you meant it was time for him to get a job.

Posted by martin_fierro

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The talk of these quantum computers and E/B condensates
is okay by me, but I just want my "air car" that was
promised decades ago. I check out the Moeller site every
now and then to find out the delivery date.

Lots of interesting thought on future discoveries, but
with the availability of medicines for male pattern
baldness and erectile dysfunction, the most important
questions of science have already been addressed.

Posted by Lawgvr1955

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Quantum matter cannot be controlled or utilized until a
substance can be created or found upon which quantum
matter can exist.
An you can quote me on this.

Posted by Khurkris

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End of forwarded messages from:

http://freerepublic.com/focus/f-news/1105926/posts

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The terrorist mission of Jesus stated in the Christian bible:

    "Think not that I am come to send peace on earth:
I came not so send peace, but a sword.
    "For I am come to set a man at variance against his
father, and the daughter against her mother, and the
daughter in law against her mother in law.
    "And a man's foes shall be they of his own
household.
- Matthew 10:34-36.

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