44 | New Scientist | 14 March 2020
expense of other attributes like accuracy or
speed. These are exactly the kinds of trade-offs
non-equilibrium thermodynamics predicts.
As an example, most computers are
governed by a single central processing unit
that controls all other components. This
centralisation is powerful, but means billions
of instructions need to be fired off every
second with incredible accuracy, at significant
energy cost. By contrast, nature gives every
cell in the body the power to independently
implement the instructions contained in DNA,
allowing them to perform in unison without
the need for a conductor. That means that a
process like DNA copying is able to trade speed
and reliability for far greater efficiency. If we
want to mimic nature’s extreme efficiency,
we may have to borrow some of these ideas.Computing 2.0
What such a dramatic paradigm shift would
look like in computing is hard to imagine,
admits Crutchfield, but it holds vast promise.
Despite its rapid growth, the internet of things
is hamstrung by the need to power billions
of small devices, often in locations that make
them hard to recharge. In these circumstances,
being able to mimic the slower – but ultra-low
power – distributed computing seen in nature
could be very attractive.The hardware of the future is unlikely
to stray far from today’s chips and circuit
boards, says Crutchfield, as that is the only
approach we know how to scale. However,
a hybrid approach combining traditional
computing logic with components that
harness thermodynamic effects is a likely
starting point. The cryogenically cooled
superconducting circuits used in quantum
computers hold promise too, says Crutchfield,
as they can also operate under conditions
where non-equilibrium physics dominates. He
has recently teamed up with applied physicists
to test some of the field’s predictions on these
circuits, and says they could conceivably be
scaled up for more sophisticated computing.
Not everyone is sold. The most glaring
problem is that most work so far has dealt with
theoretical circuits processing just a few bits
of information. On the scale of today’s silicon
chips, though, these thermodynamic benefits
would pale into insignificance compared with
the waste energy they produce. “I’m all in
favour of theory, but sometimes it just ignores
reality,” says Eli Yablonovitch at the University
of California, Berkeley.
Bridging the divide between theory and
engineering will take a lot of work from
both sides, says Stephanie Forrest of Arizona
State University. For one thing, the new
mathematical tools that work on the levelEdd Gent is a freelance writer
based in India. He tweets at
@eddythegentof bits rapidly become intractable once
you start scaling them up. She believes that
significant mathematical shortcuts will be
needed before real-world computers can
start benefiting from these breakthroughs.
Crutchfield agrees. That is why his research
programme for the next decade will be
dominated by putting the new ideas to the test.
All the same, he wouldn’t be surprised to see
significant progress before then. “Maybe in
about five years, people are going to appreciate
what a huge revolution this has been,” he says.
There are signs people are starting to
appreciate it now. X, the so-called moonshot
arm of tech giant Alphabet, recently hired
Crooks to look into the potential applications
of non-equilibrium thermodynamics. There
are serious practical difficulties to putting
these ideas to work, he says, but he doesn’t
see any fundamental barriers.
“It’s not just a question of an incremental
change in the energy dissipation of the things
we’ve got now,” says Crooks. “It would enable
entirely new things.” In a world awash with
data, that could be just the lifeline we need. ❚SOURCE: WORLD ECONOMIC FORUM607.5gDriving 5 kilometresUsing a smartphone for a dayOne hour of offline
gaming on a PS4Running a
Wi-Fi router
for 24 hoursStreaming a
film on NetflixDownloading
1 GB of dataSending an emailRunning a
Google search47g42g41g20g17g1g0.085g of CO 2 equivalentDigital footprint
The energy required for the enormous global infrastructure built to process our
data means that even everyday tasks have a carbon footprintin a diesel car
607 5g200150100500
2010 2015 2020 2025Data volume (zettabytes)Data hungry
The volume of all our data is projected to balloon
to 175 zettabytes (trillion gigabytes) by 2025SOURCE: STATISTA.COM“ Being able to mimic the
slower, but ultra-low power
computing seen in nature
could be very attractive”