28 September 2019 | New Scientist | 5A MOMENTOUS claim has been
made in a paper posted on a NASA
server. It says that Google has built
a quantum computer and proved
that it can do a calculation that
would be practically impossible
for even the world’s fastest
supercomputer.
If this is true, it is big news.
Quantum computers have the
potential to change the way we
design materials, plan logistics,
build artificial intelligence and
break encryption. That is why
firms like Google, Intel and IBM,
along with plenty of start-ups,
have been racing to reach this
crucial milestone – known as
quantum supremacy.
However, the claim is shrouded
in intrigue. The paper was quicklytaken down from the server and
Google hasn’t commented on it.
A copy of the paper seen by
New Scientist contains details
of a processor called Sycamore
that contains 54 superconducting
quantum bits, or qubits. The
paper says that Sycamore has
achieved quantum supremacy
and that the development
“heralds the advent of a much-
anticipated computing paradigm”.
Only one author is identified:
John Martinis at the University
of California, Santa Barbara, who
is known to have worked with
Google to build the hardware
for a quantum computer.
The news isn’t entirely
unexpected. In 2018, Google
reached an agreement withNASA to help test its quantum
chip. This may explain why the
paper was posted to a NASA server.
To prove the quantum
supremacy of its chip, the paper
says that Google set it a random
sampling problem – that is,
checking that a set of numbers hasa truly random distribution. This
is very hard for a conventional
computer when there are a lot
of numbers involved.
But Sycamore does things
differently. Although one of its
qubits didn’t work, the remainingGoogle may have made a huge quantum computing breakthrough.
If true, it marks a new era for the technology, reports Chelsea WhyteQuantum supremacy?
News
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First glimpse of what
our extinct cousins
looked like pGoogle has built several
quantum computers,
including this prototype“ The quantum machine took
minutes to solve a problem
that would require 10,
years on a supercomputer”53 were quantum entangled with
one another and used to generate
a set of binary digits and check
their distribution was truly
random. The paper calculates the
task would have taken Summit,
the world’s fastest supercomputer,
10,000 years. Sycamore did it in
3 minutes and 20 seconds.
“The thing they’ve
demonstrated is not in any
way useful and the quantum
computer they’ve used isn’t
anywhere near the level that
we’ll need to, say, break encryption.
But as a scientific milestone, it’s
huge,” says Ciarán Gilligan-Lee at
University College London.
Jim Clarke at Intel Labs said
in a statement that achieving
quantum supremacy was a
“notable mile marker as we
continue to advance the potential
of quantum computing”. But he
said we are still at “mile one of
this marathon”.
In future, quantum chips
may be useful in fields including
machine learning, materials
science and chemistry. For
example, when trying to model
a chemical reaction they ought
to be capable of handling vast
numbers of variables to create
accurate simulations.
At the same time, classical
computing isn’t giving up the
fight. Over the past few years, as
quantum computing took steps
towards supremacy, classical
computing moved the goalposts
as researchers showed it was able
to simulate ever more complex
systems. This back-and-forth
will probably continue.
The posted paper
acknowledges that classical
computing’s abilities will continue
to grow. “But we also expect they
will be consistently outpaced by
hardware improvements on larger
quantum processors,” it says. ❚