THURSDAY,OCTOBER24,2019 | THEGLOBEANDMAILO A
In 200 seconds – the time it takes
to poach an egg – a quantum
processor has performed a nu-
merical task faster than any
known computer system on
Earth.
Exactly how much faster is up
for debate, but the breakthrough
achievement led by researchers
at Google AI in Mountain View,
Calif., is the most convincing
demonstration yet of a feat re-
ferred to as “quantum suprema-
cy.” In essence, it means that a
quantum computer – a device
that leverages what Albert Ein-
stein once described as “spooky”
physics at the atomic scale – has
attained a level of performance
that is impractical, if not impos-
sible, for conventional computer
systems to emulate.
What’s more, researchers said,
the design of their quantum proc-
essor is one that can be improved
and scaled up. If that assessment
proves correct, the device points
the way to a game-changing tech-
nology that could revolutionize
and disrupt a range of computer-
related fields and applications.
“It’s really exciting because the
physics came through. The phys-
ics was right,” said John Martinis,
the senior scientist on the project
during a conference call with re-
porters on Wednesday. “There’s
clearly a lot of hard things to solve
... but we feel there’s a really great
future ahead of us.”
Although still a nascent tech-
nology, quantum computers of-
fer a powerful advantage over
standard digital computer in one
key respect. While an ordinary
computer operates based on bits
of information that are designat-
ed by either 1 or 0 (corresponding
physically to “off” or “on” in a cir-
cuit on a microchip) a quantum
computer runs on “qubits” that
quantum physics allows to hold a
mixture of those values.
Qubits can also be linked up so
that they can influence one an-
other in ways that produce rapid
short cuts for certain types of
problems. Future applications of
quantum computers range from
cybersecurity and drug develop-
ment to modelling financial mar-
kets.
The Google team developed a
53-qubit device, nicknamed Syca-
more, and fed it a set of random
instructions. They then sampled
the answers the device provided
in the form of strings of numbers
one million times, effectively em-
bedding the quantum character-
istics of the system in the an-
swers. While the exercise is nei-
ther commercially useful nor dif-
ficult for the device – the
scientists compared it to writing a
program that reads out “Hello
world” – it requires a massive se-ries of calculations to do the same
thing without qubits.
In describing their experiment
in the journal Nature, Dr. Martinis
and his colleagues said it would
take any existing state-of-the-art
supercomputer about 10,
years to reproduce Sycamore’s
output.
The claim was quickly disput-
ed by a team at IBM who issued a
result showing that a supercom-
puter can be optimized to solve
the problem in 2^1 ⁄ 2 days, reducing
the Google claim of quantum su-
premacy to the equivalent of win-
ning by a nose rather than by a
mile.
“Scientifically, both papers are
right,” said David Poulin, a phys-
icist at the University of Sher-
brooke and co-director of a re-
search program in quantum in-
formation science supported by
the Canadian Institute for Ad-
vanced Research.
The IBM response illustrates
that quantum supremacy is a
moving target, Dr. Poulin added,
thanks to constant improve-ments in the hardware and algo-
rithms that underpin the world’s
biggest computers. But while
“that may take some of the gloss”
off the Google announcement, he
said that what matters more is
that Sycamore has demonstrated
that a quantum computer can be
designed to operate at a scale that
some theorists had speculated
might be impossible in principle.
“It shows that quantum com-
puting is here for real and a signif-
icant player on the computing
landscape,” said Joseph Emerson,
a faculty member at the Universi-
ty of Waterloo’s Institute for
Quantum Computing. Dr. Emer-
son added that, going forward,
each small increase in the capa-
bility of quantum computers will
require exponential leaps by con-
ventional computers to keep up.
But quantum computers still
face big challenges. Among the
biggest is the fact that as more qu-
bits are added, it becomes in-
creasingly difficult to maintain
the conditions needed for reliable
quantum computations. To get
around this, quantum computers
can have a portion of their qubits
allocated to error correction. Dr.
Emerson is the founder of Quan-
tum Benchmark, a Waterloo star-
tup that has developed a way to
assess and improve the effective-
ness of quantum error correction.
The company is collaborating
with Google and is set to play a
role in future versions of its quan-
tum chip.
On Wednesday, Dr. Martinis
said that he expected that his
team would have a working
1,000-qubit device in about a
year, a scale at which quantum er-
ror correction would likely be-
come essential.
Some of the team members be-
hind the Google project were
trained at the Waterloo institute
or have other ties to Canada’s
quantum computing ecosystem.
Alexandre Blais, another expert
in the field at the University of
Sherbrooke, was one of the key
originators of the interconnected
superconducting loops that serve
as the qubits for the Google sys-
tem.Googleclaims‘quantumsupremacy’
Researcherssaythe
processorhasperformed
ataskataspeedthatis
potentiallyimpossible
forconventional
computerstoemulate
IVANSEMENIUK
SCIENCERE-ORTER
GoogleCEOSundar
Pichai,left,anda
researcherexamine
Google’squantum
processor.Researchers
saythedesignoftheir
quantumprocessorisone
thatcanbeimprovedand
scaledup.GOOGLE/NYTIt’s really exciting
because the physics
came through. The
physics was right.JOHNMARTINIS
SENIOR SCIENTIST ON
THE GOOGLE PROJECTNEWS |