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| DATE | 2014-07-13 |
| FROM | Ruben Safir
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| SUBJECT | Subject: [NYLXS - HANGOUT] Is Quantum Computing Here?
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http://www.bbc.com/news/science-environment-27264552
D-Wave: Is $15m machine a glimpse of future computing?
By Paul Rincon Science editor, BBC News website
D-Wave computers D-Wave is headquartered in the small tech hub of
Burnaby, near Vancouver
Continue reading the main story
Related Stories
* Study doubts quantum computer speed
* Nasa buys into 'quantum' computer
* Quantum 'world record' smashed
A Canadian firm has courted controversy with its claim to have built a
practical quantum computer, a feat thought to be decades away. Now,
independent researchers are trying to understand whether it really can
tap the strange world of quantum physics.
For the modest sum of $15m (?9m), a start-up near Vancouver will sell
you a black box the size of a garden shed with its logo emblazoned on
the side in white neon.
Not sold yet?
What if I told you the contents of the box were around 150 times colder
than interstellar space?
You still need some convincing - I get it.
How about this: The box contains a machine that can solve some of the
thorniest mathematical problems and could revolutionise computing.
Continue reading the main story
?Start Quote
Geordie Rose
Much of [the scepticism] has gone away as we've continued to advance
our technology so far beyond what anyone else has done?
Dr Geordie Rose Co-founder, D-Wave
Well, the company's sales pitch has worked on some big names - like Nasa
, Google , and defence
giant Lockheed Martin .
The Canadian start-up in question is called D-Wave
and their monolithic machine is - they claim
- nothing less than a real, working quantum computer. But not everyone
is convinced.
Quantum computing exploits the weird physics that takes hold at tiny
(atomic or sub-atomic) scales. Computers that tap the quantum realm
could carry out complex calculations much faster than their conventional
- or classical - counterparts.
While the basic units of information in classical computers are called
"bits" and are stored as a string of 1s and 0s, their equivalents in a
quantum system - qubits - can be both 1s and 0s at the same time.
This phenomenon would enable multiple calculations to be performed
simultaneously. But the qubits need to be synchronised using a quantum
effect known as entanglement, which Albert Einstein termed "spooky
action at a distance".
Scientists have struggled to entangle more than a handful of qubits, and
to maintain them in their quantum state. Lab devices suffer from
drop-out, where the qubits lose their ambiguity and become
straightforward 1s and 0s. This has ensured that quantum computers
remain confined to the lab - proofs of principle capable of solving only
elementary problems.
Headquartered in the small tech hub of Burnaby, on Canada's west coast,
D-Wave has raised upwards of $100m in venture capital from the likes of
Amazon founder Jeff Bezos and
In-Q-Tel , the venture capital arm of the Central
Intelligence Agency (CIA).
Cryogenic packaging - fridge payload A refrigerator cools the chip to a
temperature around 150 times colder than interstellar space
"The original vision of the company was simple: build a commercially
useful quantum computer as soon as possible," Vern Brownell, D-Wave's
chief executive, tells me.
"We just want to provide quantum computing resources to researchers and
businesses around the world so they can solve really hard problems,
better than they can today."
Continue reading the main story
?Start Quote
Prof Scott Aaronson
So far there's no speedup to explain?
Prof Scott Aaronson Massachusetts Institute of Technology
So when, in 2007, D-Wave staged a demonstration
of a quantum processor
called Orion that could solve Sudoku puzzles and search a public
database of drugs to find the closest match to a specific molecule -
both impressive achievements in this field - it was greeted with deep
scepticism.
Four years later, the company unveiled the "first commercially available
quantum computer", a 128-qubit machine called the D-Wave One, and this
time its claims weren't so easily dismissed. The announcement coincided
with the publication of a study supporting the machine's quantum
credentials
in Nature, one of the most prestigious peer-reviewed journals in the world.
This tempered some of the criticism, but fell short of winning over
vocal sceptics like Scott Aaronson of the Massachusetts Institute of
Technology (MIT). He thinks the firm's computers show "pretty good"
evidence for entanglement at a local level, though not necessarily on a
large scale. But he sees no evidence that this is helping boost the
performance of D-Wave's machines.
Prof Aaronson told BBC News: "The questions about 'the explanation for
the speedup' haven't even been activated yet, since so far there's no
speedup to explain!"
Mr Brownell comments: "What I think is really interesting is that
scientists and researchers are no longer arguing about whether it works,
it's how fast does it work? What's the scalability going to be?"
Continue reading the main story
What is quantum physics?
There are things we take for granted about the world around us. Let go
of your smartphone and it will fall to the ground. Pull the handle on a
drawer and it will open. These familiar rules can be described by the
principles of classical mechanics.
But in the late 19th and early 20th Centuries, scientists were beginning
to realise that classical physics could not explain certain phenomena
seen at very large and very small scales.
This spawned two revolutions: one was relativity and the other quantum
mechanics. Early experiments suggested light was a wave, rather than a
stream of particles. In quantum theory, light can be both a particle
(the photon) and a wave.
One principle central to quantum mechanics is that a particle, such as
an electron, can exist in all of its possible states simultaneously -
known as superposition. Another important idea is that of entanglement,
a phenomenon whereby objects become linked, even if they lie far apart.
The company's first commercial machine was followed in 2013 by the
D-Wave Two, powered by a 512-qubit chip called Vesuvius. Like its
predecessor, this computer is not for conventional use, but was designed
for solving optimisation problems, a particular class of mathematical
challenge that entails finding the best solution from all the possible
solutions.
Lockheed is using its D-Wave computer - housed at the University of
Southern California - to verify and validate flight software
.
Google's machine, which is shared with Nasa at the space agency's Ames
Research Center
, is
being used for machine learning, a branch of artificial intelligence
with applications in areas as diverse as voice recognition and detecting
credit card fraud.
The big name buy-in has generated serious buzz, but sceptics have not
been swayed.
"I don't care if the Messiah has come to Earth on a flaming chariot, not
to usher in an age of peace but simply to spend $10m on D-Wave's new
Vesuvius chip," Scott Aaronson wrote on his blog
, adding that the considered
opinion of an academic expert of his choice "would mean more to me than
500,000 business deals".
Everest and other peaks of the Himalayan mountain range Quantum analogy:
Standard computers "walk" across a landscape to find the lowest point
(the "optimal" solution to the maths problem), whereas D-Wave's
computers "tunnel" through the mountain range
D-Wave was founded in 1999 as a University of British Columbia spin-out
by Rose - who holds a PhD in physics and a light-heavyweight world title
in Brazilian Jiu-Jitsu - and his academic mentor Haig Farris.
"The team spent about five years, with collaborators in various kinds of
academic environments, coming to a view on the fastest way to come to
market with something useful," says Mr Brownell.
The so-called gate model underpins the vast majority of academic
research into quantum computing. This idea is based on developing the
quantum equivalents of the logic gates that form the building blocks of
circuits in classical computing.
Continue reading the main story
Quantum computing: A brief timeline
Quantum computer, conceptual artwork
* *1981 - *Richard Feynman of Caltech proposes a basic model for a
quantum device
* *1985* - David Deutsch of Oxford University describes the first
"Universal Quantum Computer"
* *1994* - Peter Shor devises algorithm that could allow quantum
devices to defeat cryptography
* *1998* - First working two- and three-qubit quantum computers are
demonstrated
* *2006* - Scientists develop first working 12-qubit platform
* *2009* - First universal programmable quantum computer unveiled
* *2012* - D-Wave Systems reveals a 512-qubit adiabatic quantum machine
But D-Wave settled on an approach called quantum annealing. Outlined in
a seminal 2000 paper by
Eddie Farhi of MIT, and others, this technique is fundamentally
different to the theory of quantum gates.
In Rose's chosen martial art of Brazilian Jiu-Jitsu, opponents start off
on their feet and typically end up grappling on the mat. The aim in
quantum annealing is also to reach the "ground state" - in this case,
the lowest energy point.
One common analogy is that of a cross-section through a mountain range.
The altitude of the landscape describes the energy, or cost, of the
solution. The aim is to find the lowest point on the map and read the
coordinates, as this gives the lowest energy, or "best", solution to the
problem.
"The way you would do it in classical computing is to walk up and down
the valleys and hills until you've found it," said Prof Alan Woodward, a
computing expert from the University of Surrey.
"What the quantum annealing process does for you is effectively to
tunnel through the mountain... until it announces: 'The lowest point I
found was X'."
"It shortcuts everything, and that's how it speeds up."
Experts say quantum annealing can't offer the performance boost
theoretically possible with gates, but proponents of D-Wave's approach
point to innate advantages, such as greater robustness to the "drop-out"
problem that plagues gate model quantum computing.
Dr Rose has even branded quantum gates the "single worst thing that ever
happened to quantum computing".
512-qubit processor The firm's chips are "superconducting", generating
no heat of their own
Whatever the route taken, efforts to build a quantum computer must
overcome daunting engineering hurdles. The circuits in D-Wave's
processors are superconducting, which means they have zero electrical
resistance and generate no heat. In order to get quantum effects, liquid
helium is used to cool the chip to 0.02 Kelvin, a shade above the
temperature known as absolute zero.
The whole system is enclosed in a so-called Faraday Cage, which blocks
external electrical fields that could interfere with quantum mechanical
behaviour.
Continue reading the main story
?Start Quote
I'm gently pleased by their boldness, to have a go and make the thing?
Prof Andrew Steane University of Oxford
Prof Andrew Steane, from the department of physics at Oxford University,
says: "If you go back five or 10 years, the initial statements coming
out of D-Wave - before they had a device to look at - were seen as
something you could ignore, because it just didn't seem credible.
"Then they produced this device, so they came up with the goods. And
it's a non-negligible device - it has serious computing power. It's just
a question of whether what it's achieving is beyond what could have been
done with a system based on classical physics."
Significant academic effort is now being thrown at this question. Last
year saw the publication of several scientific studies favourable to the
company's case, including indirect evidence for entanglement of qubits
and research by Catherine McGeoch, a professor of computer science at
Amherst College, that found the system performed 3,600 times faster on
some tests
than did a standard desktop machine.
But in January 2014, a team led by Matthias Troyer, of ETH Zurich in
Switzerland, published results of its benchmarking
of Lockheed's unit. Team members won't
comment publicly until the work is published in a peer-reviewed journal,
but in some tests devised by them, the D-Wave machine was found to
perform no faster than a classical computer.
However, company executives counter that the tests used were not the
sort where the quantum computer offers any advantage over conventional
types.
F-35B fighter Lockheed Martin is using its D-Wave computer to validate
flight software
Then in February, a team led by Prof Umesh Vazirani, of the University
of California, Berkeley, published a study
concluding that a simple,
classical computing model of interacting magnets could explain behaviour
in D-Wave's machines.
In his response to an unfavourable blog entry
about the paper penned by Dr Rose, Prof Vazirani suggested that key
questions might be answered if D-Wave were to grant researchers access
to its hardware , which is
proprietary. However, not everyone thinks this would shed much light on
the matter.
Continue reading the main story
?Start Quote
What Geordie (Rose) said was - let's build what we can do, instead
of always thinking about things that are out of reach?
Prof Alan Woodward University of Surrey
"At a high level, we know what the machine is doing: namely, it's doing
annealing to the ground state, with superconducting Josephson junctions
(paired superconductors) at 20mK (milliKelvin) temperature, in a way
that's 'mostly classical' but that has some quantum effects present, at
least at the local level," says Prof Aaronson.
"I think this research has actually reached some pretty firm
conclusions: most importantly, that the current device is /not/ getting
a speedup on the problem distributions currently being tried," he explains.
Andrew Steane says the computers show promise, but on the question of
whether they are exploiting quantum effects for performance gains he
says the studies by Troyer and Vazirani "suggest they can't yet really
make that claim".
But the company points to ongoing benchmarking of its machines by Google
and cites
other academic papers from recent
months that support their case.
Mr Brownell comments: "How many trillions have been invested in
classical computing? How many innovations and iterations of hardware
since John Von Neumann and the Bletchley Park folks?
"How much algorithm work and research around software and applications
and compilers and efficiency? We've come up with something in 10 years
that performs just as well, and maybe outperforms in some narrow cases
that entire ecosystem."
512-qubit D-wave quantum computer Nasa and Google share time on a
machine at the Ames Research Center in California
Geordie Rose told BBC News: "Scepticism implies a healthy and unbiased
doubt about new technological capabilities or scientific advancements.
Much of that has gone away as we've continued to advance our technology
so far beyond what anyone else has done."
"The negativity against pioneering companies though comes from small but
vocal groups concerned about losing access to funding, and from
commercial competitors. I believe the former will go away once these
folks realise that our success means more money for their basic science,
not less."
D-Wave's next chip, consisting of 1,024-qubits, is currently undergoing
calibration ahead of its planned release later this year. In addition to
its aforementioned customers, D-Wave has others it won't name. The firm
is now looking to expand into other potentially lucrative markets.
"As we get some more internal resources to support customers adequately,
we would like to branch out into other areas like bioinformatics, energy
exploration, finance," says Vern Brownell. "We know already there are
huge applications in each of these areas for quantum computing."
New York Stock Exchange Could the world of finance also benefit from
quantum computing?
Documents leaked by Edward Snowden reveal that the US National Security
Agency (NSA) has been conducting "basic research"
to determine whether it was possible to build a quantum computer that
would be useful for cracking encrypted communications.
But D-Wave's quantum annealing approach isn't well suited to this
application. Cryptanalysis is an area where researchers seem to agree
that the logic gate model offers more promise.
Of the company's efforts, Alan Woodward says: "The engineering
difficulties [of building quantum computers] are enormous, because of
susceptibilities to interactions from the environment and so on. What
Geordie said was - let's build what we can, instead of always thinking
about things that are out of reach. And you've got to admire that.
"I suspect it's something that's helping to move on the state-of-the-art
from an engineering perspective, even if it turns out not to be the
ultimate shape of things to come."
Andrew Steane comments: "I'm gently pleased by their boldness, to have a
go and make the thing.
"It's a bit like 'Make it and they will come'. They haven't quite got to
'they will come'. But they've made something."
Follow Paul on Twitter .
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