Theorizing atoms as a computing tool is like taking a quantum leap

Over the years, I’ve followed research in photonics (using light instead
of electrons for transmissions) and quantum-molecular computing without finding anything
of practical use. That may be changing.


At some point we’ll reach the scientific speed limits of solid-state computers
that use very large-scale integrated chips. I’m not talking about hard-drive or bus
speed limits, both of which have lots of room to grow. What I mean is that circuit
components inside a processor can’t get any smaller than one atom in width.


One atom wide is impractical, of course, because to make the necessary silicon mask,
you would have to focus a beam with high enough energy to resolve objects at the atomic
level.


Long before reaching this theoretical limit, we’d get to a point where it was no
longer cost-effective to make smaller electronic components.


Parallel processing, which uses multiple processors simultaneously, is an expensive
hardware proposition. The programming is so difficult it probably will remain in a niche.
Advances in conventional processing eventually will be tapped out.


Beyond Newtonian physics lies the mysterious world of quantum physics. Some researchers
now think they could use quantum measurements of atoms in a liquid as a computing tool.


Back in 1994, an AT&T Corp. scientist theorized a way to factor numbers on an
imaginary quantum computer. The National Security Agency has probably been working on one
ever since, because factoring lies at the heart of encryption. Finding a pair of numbers
that, when multiplied together, produce a specific large number is the basis of many data
encryption schemes.


The encryption gurus better watch out, because this new computing paradigm might make
factoring large numbers much easier—say, tens of thousands of times easier—than
it is today.


Because cryptographers worry not just about today’s code-cracking techniques but
about any theoretically possible future technology that could compromise encrypted
messages, they might need to rethink the basis of their science.


A practical use for quantum states seems fantastic at first, because of the supposed
difficulty of manipulating and measuring an atom’s quantum state.


But it turns out that nuclear magnetic resonance, used for decades in medical imaging
devices, is essentially a quantum computer.


Researchers say it’s relatively easy to use a collection of atoms as a two-state
device—a logical gate, which underlies every digital computer’s workings.


The National Institute of Standards and Technology is researching quantum-mechanical
computers. So are IBM Corp. and many universities.


Just in case you think I’ve gone completely off my rocker, consider the “Star
Trek” transporter.


It is entirely fictional to be transported because, among other things, it violates the
speed-of-light restriction that also limits how fast computers can operate. And according
to the Heisenberg Uncertainty Principle, if you tried to be transported, you would be
smeared all over the place.


But now several scientists claim to have shown that teleportation might have a
theoretical basis in reality, and someone else has found a possible endrun around
Heisenberg.


If you don’t believe me, check out Anton Zeilinger’s work at the University
of Innsbruck, Austria, on the Web at http://www.dm2.uibk.ac.at/c/c7/c704/qo/people/az.htm.


Don’t bother trying to order a quantum computer or transporter today, but quantum
computers have real potential in fields such as cryptography.


To science fiction fans, reading about quantum computers seems a lot like reading about
the infinite improbability drive in Douglas Adams’ Hitchhiker’s Guide to the
Galaxy books.


Then again, Jules Verne was predicting travel to the moon about the time the Wright
brothers were working on the first airplane.


Quantum mechanics is so weird that it’s difficult to decide just what makes sense
in this field. For information about quantum computers, check out Stanford
University’s site at http://www.feynman.Stanford.EDU/qcomp/.
For the latest word on quantum computers from Los Alamos National Laboratory, see http://p23.lanl.gov/Quantum/quantum.html.


Still think I’m crazy? You can’t get much more bottom-line than Big Blue, and
there’s actually an IBM Web page titled “Quantum
Teleportation.” It’s at http://www.research.ibm.com/quantuminfo/teleportation/
 


John McCormick, a free-lance writer and computer consultant, has been working with
computers since the early 1960s. E-mail him at powerusr@penn.com.
 

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