If
you just assume that computers will keep on getting better, faster, and
cheaper, most experts will tell you not to get your hopes up too high.
The much-touted Moore’s Law is running out of steam. Back
in 1965, Intel’s Gordon Moore predicted that the number of transistors
per integrated circuit would double every 18 months. He was pretty well
right on the money. Since more transistors generally equal more
horsepower, we’ve seen greater bang for the computer buck every year.
This also explains why your kids are always screaming for a hot new
machine and why I was just able to buy an aging Pentium for $15 because
I needed a keyboard. Computer gurus agree that
Moore’s Law is actually a tribute to good engineering at places such as
Intel and in no way an actual Law of the Universe. In fact, there are
some real Laws of Nature that work directly against it. Things such as
the speed of light and size of subatomic particles will eventually
impose speed limits on computers that use silicon chips and logic
gates. At the most optimistic end of the spectrum, prognosticators such
as Sheldon Ronan (who admits it’s a “long bet”) gives Moore’s Law about
50 years to run, until 2052. Others think that
physical reality will catch up with computers within a decade. They
point to the fact that processor-speed improvement is already dropping,
apparently only doubling every three years. Rejoice, you can now hang
on to that old laptop a little longer and not feel like a fool. But wait a minute – the answer to “Will computers keep getting better?” has just changed from no to a strong maybe. Barry
Sanders, iCore professor of quantum information science at the
University of Calgary, working with colleagues in Australia recently
announced a breakthrough in the teleportation of quantum information. Bear
with me please. Quantum information is based on quantum mechanics,
which was the part of high-school physics where you doodled as the
teacher talked about cats that are simultaneously dead and alive and
pebbles that turn to dust if light strikes them. Relax. After all,
quantum information is a little easier to grasp than full-blown
Bose-Einstein condensates. “Standard computer
science uses bits and standard Boolean logic,” explains Sanders.
“Instead, we use quantum bits (qubits) which allow the simultaneous
co-existence of all states of information in some superposition. We
also use a different form of processing that preserves that
simultaneous co-existence. This means that the foundations of computer
science and communication theory no longer apply, because we’re working
in a different space.” In other words, problems
that would baffle regular computers, or take a long, long, long time to
finish, might be child’s play for a quantum computer. While
this all sounds like the stuff of science fiction, Sanders says quantum
teleportation is a really like a common office tool. “Faxing
is a form of teleportation,” he says. “I have a piece of paper in a
particular state (with a message on it) and you want your piece of
paper to adopt the same state. The problem with quantum information is
that if you try to learn what it says, you destroy it, and if you try
to copy it, you can’t look at the copy because you’d destroy the
information on it.” So, is Sanders working on a
quantum fax machine? Not exactly. His current project involves
exchanging information between quantum computers, which, by the way,
don’t even exist yet as far as we know. So
researchers like Sanders do experiments with lasers and think real hard
about what quantum computers might be like – if we ever got one. “About
three years ago, my colleagues in Australia demonstrated the quantum
teleportation of information using laser beams,” said Sanders. “When I
saw what they had done, I suggested that quantum information could be
used to share secrets by entwining information in the laser beams,” he
says. The experiment worked, yielding a
four-page paper in Physical Review Letters, itself densely packed with
(thankfully non-quantum) information. According
to Sanders, this research has huge implications for information
security. If a quantum computer could be built, it might shatter all
existing cryptographic algorithms that depend on mathematically gnarly
problems such as factoring large numbers. An evil genius with such a
machine could wreak havoc on the world’s banking and other
security-dependent systems. Sanders’ findings
give us hope that, in his words, “quantum networks can be protected
from component failures and malice.” In particular, it points the way
to a secure method for sharing secrets among users of quantum
computers. This uses Adi Shamir’s secret-sharing protocol, which
divides data so a message can only be decoded by a majority of the
recipients. According to Australian National
University researcher Andrew Lance, “if an encrypted message was sent
to a spy network containing 15 individuals, a minimum of eight agents
would be needed to access the message,” thus limiting the risk of a
small number of double agents. An added bonus is that it’s physically
impossible to eavesdrop on a quantum information transmission without
being noticed. The U of C’s Sanders has started
to see business interest in his work, including the defence industry.
“General Dynamics Canada recently gave us money because they regard
this as a disruptive technology,” he says. “It may not be significant
right now, but they know this is a technology that may be important in
the future and they need to know about it.” Asked
if there are any true quantum computers in the world, Sanders laughs
and says that people who could build one now probably wouldn’t tell us
if they did. He predicts that it will be at least 10 to 20 years before
we see a quantum computer that can solve problems that can’t be handled
by regular computers. So relax, your kids won’t
be asking you for one soon. But, in a stroke of natural justice, their
kids just might be clamoring for that hot new Quantum PlayStation . . . Web watch: www.qubit.org/
www.qis.ucalgary.ca
http://qis.ucalgary.ca/~bsanders (Tom
Keenan is a professor at the University of Calgary and an expert on
technology and its social implications. He can be reached at keenan@businessedge.ca)
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