[ExI] Quantum Computers

[John Clark]

The following article about Quantum Computers was on page one of the
business section of today's New York Times:
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VANCOUVER, British Columbia — Our digital age is all about bits, those
precise ones and zeros that are the stuff of modern computer code. But a
powerful new type of computer that is about to be commercially deployed by
a major American military contractor is taking computing into the strange,
subatomic realm of quantum mechanics. In that infinitesimal neighborhood,
common sense logic no longer seems to apply. A one can be a one, or it can
be a one and a zero and everything in between — all at the same time.

It sounds preposterous, particularly to those familiar with the yes/no
world of conventional computing. But academic researchers and scientists at
companies like Microsoft, I.B.M. and Hewlett-Packard have been working to
develop quantum computers.

Now, Lockheed Martin — which bought an early version of such a computer
from the Canadian company D-Wave Systems two years ago — is confident
enough in the technology to upgrade it to commercial scale, becoming the
first company to use quantum computing as part of its business.

Skeptics say that D-Wave has yet to prove to outside scientists that it has
solved the myriad challenges involved in quantum computation.

But if it performs as Lockheed and D-Wave expect, the design could be used
to supercharge even the most powerful systems, solving some science and
business problems millions of times faster than can be done today.

Ray Johnson, Lockheed’s chief technical officer, said his company would use
the quantum computer to create and test complex radar, space and aircraft
systems. It could be possible, for example, to tell instantly how the
millions of lines of software running a network of satellites would react
to a solar burst or a pulse from a nuclear explosion — something that can
now take weeks, if ever, to determine.

“This is a revolution not unlike the early days of computing,” he said. “It
is a transformation in the way computers are thought about.” Many others
could find applications for D-Wave’s computers. Cancer researchers see a
potential to move rapidly through vast amounts of genetic data. The
technology could also be used to determine the behavior of proteins in the
human genome, a bigger and tougher problem than sequencing the genome.
Researchers at Google have worked with D-Wave on using quantum computers to
recognize cars and landmarks, a critical step in managing self-driving
vehicles.

Quantum computing is so much faster than traditional computing because of
the unusual properties of particles at the smallest level. Instead of the
precision of ones and zeros that have been used to represent data since the
earliest days of computers, quantum computing relies on the fact that
subatomic particles inhabit a range of states. Different relationships
among the particles may coexist, as well. Those probable states can be
narrowed to determine an optimal outcome among a near-infinitude of
possibilities, which allows certain types of problems to be solved rapidly.

D-Wave, a 12-year-old company based in Vancouver, has received investments
from Jeff Bezos, the founder of Amazon.com, which operates one of the
world’s largest computer systems, as well as from the investment bank
Goldman Sachs and from In-Q-Tel, an investment firm with close ties to the
Central Intelligence Agency and other government agencies.

“What we’re doing is a parallel development to the kind of computing we’ve
had for the past 70 years,” said Vern Brownell, D-Wave’s chief executive.

Mr. Brownell, who joined D-Wave in 2009, was until 2000 the chief technical
officer at Goldman Sachs. “In those days, we had 50,000 servers just doing
simulations” to figure out trading strategies, he said. “I’m sure there is
a lot more than that now, but we’ll be able to do that with one machine,
for far less money.”

D-Wave, and the broader vision of quantum-supercharged computing, is not
without its critics. Much of the criticism stems from D-Wave’s own claims
in 2007, later withdrawn, that it would produce a commercial quantum
computer within a year.
There’s no reason quantum computing shouldn’t be possible, but people
talked about heavier-than-air flight for a long time before the Wright
brothers solved the problem,” said Scott Aaronson, a professor of computer
science at the Massachusetts Institute of Technology. D-Wave, he said, “has
said things in the past that were just ridiculous, things that give you
very little confidence.”

But others say people working in quantum computing are generally optimistic
about breakthroughs to come. Quantum researchers “are taking a step out of
the theoretical domain and into the applied,” said Peter Lee, the head of
Microsoft’s research arm, which has a team in Santa Barbara, Calif.,
pursuing its own quantum work. “There is a sense among top researchers that
we’re all in a race.”

If Microsoft’s work pans out, he said, the millions of possible
combinations of the proteins in a human gene could be worked out “fairly
easily.”

Quantum computing has been a goal of researchers for more than three
decades, but it has proved remarkably difficult to achieve. The idea has
been to exploit a property of matter in a quantum state known as
superposition, which makes it possible for the basic elements of a quantum
computer, known as qubits, to hold a vast array of values simultaneously.

There are a variety of ways scientists create the conditions needed to
achieve superposition as well as a second quantum state known as
entanglement, which are both necessary for quantum computing. Researchers
have suspended ions in magnetic fields, trapped photons or manipulated
phosphorus atoms in silicon.The D-Wave computer that Lockheed has bought
uses a different mathematical approach than competing efforts. In the
D-Wave system, a quantum computing processor, made from a lattice of tiny
superconducting wires, is chilled close to absolute zero. It is then
programmed by loading a set of mathematical equations into the lattice.

The processor then moves through a near-infinity of possibilities to
determine the lowest energy required to form those relationships. That
state, seen as the optimal outcome, is the answer.

The approach, which is known as adiabatic quantum computing, has been shown
to have promise in applications like calculating protein folding, and
D-Wave’s designers said it could potentially be used to evaluate
complicated financial strategies or vast logistics problems.

However, the company’s scientists have not yet published scientific data
showing that the system computes faster than today’s conventional binary
computers. While similar subatomic properties are used by plants to turn
sunlight into photosynthetic energy in a few million-billionths of a
second, critics of D-Wave’s method say it is not quantum computing at all,
but a form of standard thermal behavior.

 John Markoff contributed reporting from San Francisco.
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