New_Scientist_11_2_2019

2 November 2019 | New Scientist | 21

Q

UANTUM computing
has hit the big time.
In a paper leaked online
just over a month ago, Google
said it had performed the first
quantum computation that was
beyond an ordinary machine,
a milestone known as quantum
supremacy. Since then, the
headlines have been breathless.
Google’s achievement has been
heralded as doing everything from
breaking the internet to solving
the climate crisis. But let’s stop and
breathe. Quantum computing’s
true potential is still decades away
and hitting peak quantum now
may scupper the whole endeavour.
Part of the excitement came
from the secretive nature of the
reveal. Despite the leak, Google
refused to comment until the
paper’s official publication in
Nature last week. This led to a
build-up of buzz usually reserved
for the likes of a new iPhone.
In truth, the hype has been
growing for more than a decade.
For most of that time, quantum
computing has felt as elusive as
other forever-around-the-corner
tech, such as nuclear fusion. The
media and industry have played
up its virtually limitless potential:
these devices will be able to model
new drugs and materials, simulate
the climate and financial systems
in unprecedented detail, break
cryptography, and much more.
“The real excitement about
quantum is that the universe
fundamentally works in a
quantum way, so you will be able
JOSIE FORDto understand nature better,”

Comment

Views

The columnist

Chanda Prescod-

Weinstein praises

neutron stars p22

Letters

Artificial intelligence

may need to be

socialised p24

Aperture

The sun comes out

over the MeerKAT

radio telescope p26

Culture

Can we now explain

why consciousness

evolved? p28

Culture columnist

Gemini Man has

two big logical flaws,

says Simon Ings p30

Google’s CEO, Sundar Pichai,

told MIT Technology Review.

Well, not with this computer.

From an engineering perspective,

the result is impressive. Quantum

systems are hard to control and

manipulate even for a fraction of

a second. But Google’s quantum

device does nothing useful.

John Preskill at the California

Institute of Technology, who

coined the term quantum

supremacy, has pointed out

that Google deliberately chose

a narrow task that a quantum

computer would be good at and

a classical computer is bad at.

The “supremacy” part also

suggests that quantum computers

outperform classical ones across

the board, which isn’t true. Classical

computers are likely to remain

better than quantum machines

for most everyday tasks. Sorry, but

you won’t get a quantum laptop.

Pichai has compared his

company’s achievement to the

Wright brothers’ first flight – an

apt analogy. Orville Wright flew for

12 seconds, which was a stunning

proof of concept but little more.

It took years of work before there

were reliable, long-distance

flights, and decades more before

passenger jets made a difference

to the average person’s life.

Pichai also said that he thinks

quantum computing will be as

important as artificial intelligence,

which may be the better

comparison. Wild claims about

AI have brought disappointments.

There is even a name for it: AI

winter. When reality fails to live up

to people’s expectations, funding

dries up and researchers move on.

To avoid a quantum winter, we

should dial down the hype. A lot of

companies are chasing a quantum

pay-off, but it is a gamble. Can we

make chips that scale up and are

accurate enough to do anything

useful? If practical devices prove

elusive, will firms keep at it or

veer off to easier wins? Google

in particular has a reputation for

killing projects it loses interest in.

It has taken Google 13 years to

get this far. Without a profitable

device, research could dry up.

It happened with the Apollo

programme. It has happened

at times with AI.

Ultimately, quantum supremacy

is a waypoint, not the destination.

It is quantum advantage – showing

that computers can do something

useful that others cannot – that

will be truly exciting. Just don’t

hold your breath. ❚

Beware quantum winter

Google’s quantum breakthrough is the first step on a long road.

Let’s make sure we don’t stumble, says Douglas Heaven

Douglas Heaven is

a consultant for New

Scientist. You can follow

him on Twitter @strwbilly