From digital to quantum computers - or from semiconductors to superconductors (Nicola de Liso)

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From digital to quantum computers
- or from semiconductors to superconductors
Nicola De Liso (University of Salento, Lecce, Italy)
e-mail: nicola.deliso@unisalento.it
European University Institute – Florence School of Regulation – 9th Annual Scientific seminar on “Media and
the Digital Economy”, Florence – 21-22 March 2019
European University Institute
9th Annual Scientific Seminar on “Media and the Digital Economy”
Florence, 21-22 March 2019

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The tale which we tell today
The tale which we tell today begins in 1908 with
the liquefaction of helium (a gas) and ends up
with the first computer making use of quantum
phenomena in 2013.
This is a tale based on radical innovation, and
the story will run as follows:
European University Institute – Florence School of Regulation – 9th Annual Scientific seminar on
“Media and the Digital Economy”, Florence – 21-22 March 2019

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Contents
• Innovation and technical change as driving forces
of (market) economies
• The phenomenon of superconductivity and
superconductors
• ‘Presumptive anomaly’, semiconductors and
superconductors
• From ‘digital classical’ to ‘quantum’ computers
• Conclusions
European University Institute – Florence School of Regulation – 9th Annual Scientific seminar on “Media and
the Digital Economy”, Florence – 21-22 March 2019

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Innovation - 1
The most common concepts are those of
‘product’ and ‘process’ innovation.
Innovation in both cases has a double meaning:
‘product innovation’ meaning a new version of an
existing product (e.g. digital watches vs.
mechanical watches), or creating an entirely
product which did not exist (the computer);
‘process innovation’ meaning a modified version
of an existing production process, or creating an
entirely new process of production (e.g. different
production processes to produce steel).

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Innovation - 2
“The prophet of innovation”, namely Joseph
Schumpeter, defines as innovation:
(1) The introduction of a new good … or of a new
quality of a good. (2) The introduction of a new
method of production … (3) The opening of a
new market … (4) The conquest of a new source
of supply of raw materials or half-manufactured
goods … (5) The carrying out of the new
organisation of any industry, like the creation of a
monopoly position … or the breaking up of a
monopoly position (Schumpeter,1934, p. 66)

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Innovation - 3
Many more questions may be raised:
Does innovation in services have the same
characteristics as innovation in industrial
sectors?
Different ways of ‘pricing’ a commodity or a
service may be also considered as ‘innovation’.

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Innovation - 4
When we look at what affects innovation the
dimensions which we have to consider are
numerous. A non-exhaustive list includes:
firm size and innovation; market structure and
innovation; demand-pull, technology-push; the
relationship between R&D, invention and
innovation; technology adoption (technologies
cannot simply be adopted but must be adapted);
systemic views: ‘national’ or ‘sectoral’ systems of
innovation; the role played by patents; the role
played by governments and, more specifically,
by defence-related needs; …

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Near-absolute zero temperatures and
helium liquefaction
Absolute zero is -273 °Celsius1, or 0 Kelvin, and
is the lowest limit of the temperature scale.
The liquefaction of helium, a gas, was obtained
in 1908 in a high-tech laboratory built by the
Dutch physicist Heike Kamerlingh Onnes. That
liquefaction required reaching a record low
temperature -269° (or 4K).
1 -273,15 to be precise

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Near-absolute zero temperatures and
superconductivity
To understand the meaning of ‘superconductivity’
we must refer to electrical resistance. All
materials show some resistance to the passage
of an electric current. This law does not hold for
certain materials when temperatures close to 0K
are reached: resistance drops to zero.
In 1911 a technician working in Kamerlingh
Onnes laboratory, observed the sudden
disappearance of mercury’s resistivity at 4.2 K:
superconductivity had been discovered.

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The computer world: from vacuum tubes
(or valves) to semiconductors
“The first fully electronic machine, the ENIAC,
[was] built in 1946 … [and] had 18,000 valves and
diodes to be changed frequently.”
The patent for transistors was filed in 1948. The
transistors revolution was fully accomplished in 10
years:
“Hot, unreliable and power-consuming valves were
no longer necessary and became obsolete for
computers in 1958.”
Both quotes are from: E. Braun & S. MacDonald, 1978, Revolution in
Miniature, p. 188.

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The happy world of semiconductors
Transistors (1948), integrated circuits (1959),
microprocessors (1971).
‘Moore’s law’: “Cramming more components onto
integrated circuits” (G. Moore, 1965). He estimates
the accelerated reduction of manufacturing
transistors costs together with the doubling of the
number of transistors per circuit every 12 months.
For the decade 1966-1975 this prediction showed
to be accurate. Then it slows down to the version
which sees a doubling of transistors per chip every
18-24 months.

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In the meantime IBM ..
In the mid-1950s IBM started to experiment with
superconductors in memory systems by using
the cryotron – the first device which exploited
superconductivity.
IBM was working keenly on this early
superconducting technology, devoting resources
to it, also supported by funding from the US Air
Force: fast computing has always been of
interest for Defence Agencies.

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A key scientific achievement
In 1962 the British physics PhD student Brian
Josephson published a theoretical key article on
what was going to be later defined as the
Josephson effect.
He demonstrated that electrons can cross a non-
superconductive barrier and a ‘supercurrent’, in
appropriate conditions, can flow between two
superconductors. That was the theoretical basis
for the future production of Josephson junctions.

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What a ‘Josephson junction’ is not
Josephson junctions are not faster transistors:
they are devices based on completely different
scientific and technological principles.
They are substitutes for transistors, provide the
same service, and they do it much faster.

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Mid-1960s: IBM’s move
“The combination of high speed, sharp threshold,
and strong magnetic field dependence makes
Josephson junctions attractive as logical
elements” (Matisoo, 1966)
Despite semiconductors progresses, in the late
1970s it looked like superconductors could
eventually win the market: “Josephson tunnelling
devices … could indeed be switched very fast
and could be competitive with projected semi-
conductor integrated circuits” (Anacker, 1980).

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The big investment
The new technology looked very promising and
from the mid-1960s IBM invested heavily in it: a
team of 100 to 120 researcher, endowed with
dedicated laboratories and massive funding, was
working on the ‘Josephson computer’ project.
In 1980 IBM believed that it was very close to
revolutionise the computer world:

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Scientific American, May 1980

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From enthusiasm to the demise of the
superconducting computer
“On 23 September [1983], IBM ended its attempt
to build a high-speed, general-purpose computer
whose guts would be logic and memory chips
made of superconducting Josephson junction
switches”: thus wrote Arthur L. Robinson in the
November 1983 issue of Science.

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Why did IBM invest in this technology?
Because of the ‘presumptive anomaly’ principle:
“Presumptive anomaly occurs in technology, not
when the conventional system fails in any absolute
or objective sense, but when assumptions derived
from science indicate either that under some
future conditions the conventional system will fail
(or function badly) or that a radically different
system will do a much better job. No functional
failure exists; an anomaly is presumed to exist;
hence presumptive anomaly.” (Constant, 1980,
The origins of the turbojet revolution)

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The ‘presumptive anomaly’ principle
at work - 1
When IBM decided to invest in superconductors,
semiconductors were developing at an
accelerated rate, and Moore’s law was working
restlessly.
However, the ‘law’ is bound to saturate: it cannot
last forever. There are limits set by physics to
miniaturization, and cramming more and more
transistors in the same volume creates
insurmountable heat problems.

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The ‘presumptive anomaly’ principle
at work - 2
In the late 1970s it was reasonable to expect that
‘Moore’s law’ was close to the saturation point.
It was thus necessary to look for a new
technology which could guarantee the
continuation of the development of computing
capability at the same, or higher, rate.

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Wrong expectations are rational
In hindsight one might be induced to classify IBM
‘Josephson computer project’ as a massive
waste of resources.
Ex-post we are all capable to teach lessons, but
it can be shown that the IBM’s decision to invest
in this project can be defended on both
technological and economic ground.

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The end of the story?
So, are we here to talk about a revolutionary
technology which never materialised, and which
died in 1983?

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«Coup de théâtre»: 17th February 2014
The “infinity
machine”
(produced by the
company D-Wave)
operates at 273°
below zero.
It uses
superconducting
Josephson
junctions

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Opening the way to quantum computers
The company D-Wave claims to have put in
routine use the first computer making use of
quantum mechanics.
Physicists, mathematicians and computer
scientists have been toying with the idea of
quantum computing since the 1980s, but the
practicalities in order to build such a machine
present many difficulties.

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The quantum computing race
Problems have been overcome in the last few years.
Picture taken from The Economist, 20th June 2015

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The science of classical physics
Quantum mechanics is weird and counter-
intuitive.
“Before quantum mechanics came along … it
was taken for granted that when physicists
measure something, they are gaining knowledge
of a pre-existing state”. (Lindlay, 1996, Where
does the weirdness go?)
When I measure the Moon’s circumference, the
Moon is there, and my measurement does not
make any difference to it – it exists
independently of my measurement, nor does it
exists because I measure it.

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From science to science fiction
When we deal with electrons and elementary
subatomic particles the principle of
indeterminacy emerges:
“[S]ome things are not determined except when
they are measured, and it’s only by being
measured that they take on specific values. […]
The act of measurement does not simply yield
information about a preexisting state, but rather
forces a previously indeterminate system to take
on a definite appearance.” (Lindlay, 1996).

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From science fiction back to
(everyday) science
Put in another way, the ‘subatomic’ Moon exists
only when I measure it (Einstein), cats can be
dead and alive at the same time (Schroedinger),
particles can be in two different places at the
same time and, by the way, particles are not
necessarily particles, as they behave also like
waves.
Never mind if you get confused: after all, except
for a limited number of extra-terrestrial beings,
basically nobody understands quantum
mechanics (even though we can exploit it).

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Classical and quantum computing
As far as computers are concerned:
classical computers work with bits than can either
be 0 or 1 (the binary way of computer life);
quantum computers use qubits which can take
value 0, 1 and any combination between 0 and 1
at the same time; the final part of the latter
statement is ‘explained’ by saying that quantum
computers exploit ‘superposition’.
Whatever the latter statement means, it implies
fast(er) computing rates.

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The basic technical devices
2017 IBM power9, 4GHz,
14nm semiconducting
processor unit
2015 IBM 4 bit quantum chip,
A.D. Córcoles et al. Nature
Communications
Superconductivity is not the only possible avenue
to quantum computing, but at the moment it seems
to be the most promising.

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The other soft and hard components
Production of quantum computers requires the
development of a new technological paradigm
and technological subsystem:
new hardware, software, algorithms and control
technologies must be developed.

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‘Quantum’ not always better than ‘classical’
Quantum computation will not be necessarily
better in all kinds of computation. Furthermore,
quantum computation is particularly ‘noisy’.
In ‘classical’ computers, where bits are 0 or 1 it is
easy to control noise.
“Because a qubit can be any combination of one
and zero, qubits and quantum gates cannot
readily reject small errors (noise) that occur in
physical circuits. As a result … small errors …
can eventually lead to wrong outputs” (National
Academies of Sciences, 2018, Quantum
computing: progress and prospect)

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‘Quantum’ better than ‘classical’ in one key field
One field in which quantum computers will be
able to solve problems which cannot be solved by
classical computers is cryptography.
All the transactions which take place through the
Internet – e.g. buying something with a credit
card – are protected as encrypted data.
Breaking that encryption would take an infinite
time to a classical computer, but it would take a
finite time to a quantum computer – as
demonstrated in an article by the applied
mathematician Peter Shor published in 1994.

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What next?
We expect to get continuously improved ‘smart’
technologies, faster, more reliable, with all the
information always and everywhere available.
We are entering the fifth generation (5G) of
mobile communication, so that we have gone
through the ‘naïve’ Internet, the ‘Internet of
things’ and now the ‘Internet of everything’.
But until today we have been progressing along
a fairly ‘predictable’ trajectory.

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The technological singularity
The real question becomes: are we getting
closer to the ‘technological singularity’ and
‘intelligence explosion’?
Using V. Vinge words, technological singularity is
a point where our models must be discarded and
a new reality rules; technological progress is
taking us to an edge of change comparable to
the rise of human life on Earth, the cause of this
change being the creation of entities with
greater-than-human intelligence (Vinge, 1993,
The coming technological singularity)

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Quantum computers and artificial intelligence
Quantum computers could provide the hardware
basis on which artificial intelligence could get the
boost to reach what Jack Good calls the
‘intelligence explosion’:
“the first ultraintelligent machine is the last
invention that man need ever make”.
The final step would be the age of spiritual
machines (Kurzweil, 1999)

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Thank you
for your
attention

From digital to quantum computers - or from semiconductors to superconductors (Nicola de Liso)

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