
Disruption is coming with quantum computing - isaiahg
http://singularityhub.com/2016/10/10/massive-disruption-quantum-computing/
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mathgenius
The phrase "quantum supremacy" sounds click-baity but it's actually bona-fide
jargon. These guys are working with complexity theorists, such as Scott
Aaronson and Michael Bremner, to nail down specific tasks that are going to be
completely impossible for classical computing. Part of the motivation is to
move beyond the whole D-wave saga, and build something that for-sure kicks the
shit out of current classical computing technology. Calling it "quantum
supremacy" is a nice bit of marketing, imho.

Earlier this year I sat down with the guy that runs the google quantum
computing lab (Hartmut Neven) and chatted a bit about what they are building.
One of the ideas is to be able to re-purpose silicon fab technology; whoever
gets this to work (if it's possible) is going to win big.

There are many other approaches being explored, by many research labs around
the world. One particularly interesting idea is to use photonics (think fiber-
optics), which has the great advantage of not needing to be ridiculously cold
[1].

Source: me doing a PhD in the area.

[1] [https://arxiv.org/abs/1607.08535](https://arxiv.org/abs/1607.08535)

~~~
philippnagel
Could you elaborate on "repurpose silicon fab technology"? I know pretty much
nothing about quantum computing. How does the manufacturing process differ?

~~~
ThePhysicist
Most superconducting qubits, such as the "Transmons" used by Google and
various other labs are made of Aluminium, as this is a material which has good
properties and can be easily deposited using e.g. evaporation-based methods
(i.e. heat Aluminium in a vacuum so it evaporates and gets deposited on the
surface of a chip that you put nearby). The microwave circuits on the chips
are typically made out of Niobium (another superconductor), which is not very
suited for making qubits but which provides very good properties for building
large-scale structures such as coplanar waveguides.

To fabricate a qubit, normally one first deposits Niobium on a Saphire/Silicon
wafer and then etches structures into this using photo lithography.
Afterwards, the Aluminium qubits get deposited using so-called shadow
evaporation technique, where you create two layers of Aluminium separated by a
thin insulating barrier that is created by first depositing a single layer of
Aluminium, oxidizing it and then depositing another layer of Aluminium at a
different angle. This process is quite finicky and the yield of working qubits
you get out of it is (or at least was at the time I worked on this) rather
low. Adapting techniques from conventional semiconductor manufacturing (were
error rates are < 1^-9 per transistor) seems therefore very promising. So far
it seems that there are still many hurdles to overcome for this, though the
fabrication methods get more reliable every year.

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ThePhysicist
Martinis has been working on a quantum supremacy demonstration chip for a few
years already, and it's not unrealistic that they will make it work in the
next 12-18 months. The term "supremacy" is a bit misleading though as it
suggests that general purpose quantum computing might be around the corner,
which it is not.

The "supremacy" algorithm is designed to demonstrate -for the first time- a
quantum processor that runs an algorithm which cannot (or just barely can) be
simulated on a classical computer (due to the number of qubits in the system).
The circuit they're using for this contains around 45 qubits (which is enough
to make a classical simulation very hard) and the result of the algorithm that
runs on it can be verified using a conventional supercomputer (as otherwise it
would be hard to prove that it actually did what it's meant to do). So all in
all this is a very clever way of demonstrating the possible supremacy of a
quantum computer with the currently available means of technology, but it's no
general purpose quantum computer.

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sgt101
Quantum Supremacy sounds amazing, like a blockbuster movie! One imagines a
disjunctive change, with humans either assuming the mantles of wise, beautiful
gods or being dragged, screaming, from their place at the head of nature by
blank eyed quantum computing powered robot deamons.

But actually my understanding is that the people who are driving the Quantum
Computing research agenda mean something fundamental which is very distantly
related to application. Quantum supremacy will be declared when :

"But what quantum supremacy means to me, is demonstrating a quantum speedup
for some task as confidently as possible. Notice that I didn’t say a useful
task! I like to say that for me, the #1 application of quantum computing—more
than codebreaking, machine learning, or even quantum simulation—is just
disproving the people who say quantum computing is impossible! So, quantum
supremacy targets that application."
[[http://www.scottaaronson.com/blog/?p=2943](http://www.scottaaronson.com/blog/?p=2943)]

Also, the article doesn't point out that there are many people working on this
internationally, there are groups in the UK and Australia which are developing
differentiated approaches which have a strong chance of underpinning the
technology for QS - preserving QBITs for long periods and creating large
numbers of them which can be usefully manipulated.

~~~
partykid92
cmon now. This is a good attempt at pandering to the hackernews audience by
being skeptical and cynical, but Quantum Supremacy is a big deal. From the
same article:

If I have any policy advice, it’s this: recognize that a clear demonstration
of quantum supremacy is at least as big a deal as (say) the discovery of the
Higgs boson. After this scientific milestone is achieved, I predict that the
whole discussion of commercial applications of quantum computing will shift to
a new plane, much like the Manhattan Project shifted to a new plane after
Fermi built his pile under the Chicago stadium in 1942.

~~~
sgt101
I didn't want to be skeptical, much less cynical. I agree with the second bit
of the article too but the operative word for me is if!

If a * clear* demonstration happens things will change, alot.

But this has not yet happened, it may never happen, that's science! Personally
I bet into 5 or more years but would be delighted to be wrong.

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isaiahg
I can't find any other source for this claim. It's written by Dr. Peter
Diamandis. I don't know who he is, but his biography seems impressive. Could
this be true?

Statement is about 2/3 down the article.

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lisivka
It's very unlikely. Quantum computing is just a bunch of random generators
(very fast generators indeed) with bunch of filters on top of them. They good
for searching a solution in broad space, but that is all. It's reinvention of
analog computing with electric models, but using new tech.

~~~
bnegreve
_" Searching for a solution in a broad space"_ describes virtually every hard
problem in computer science.

For example optimization problems are everywhere. In planning or in machine
learning, just to name a few.

Having efficient ways to solve such problems would very definitely make a
difference.

I agree that it's unlikely to happen anytime soon, though.

~~~
lisivka
The problem with analog computing was that they tend to oscillate or pickup
noise which greatly limits their usefulness for precise calculations. With
quantum computing, you will need to use series of runs and average them. For
simple cases, it will be e.g. 10 runs, for complex cases you may need
thousands or millions of runs. IMHO, it still will be faster (because quantum
produces random values at mach faster rate than macrosystems), but (IMHO)
efficient quantum algorithms can be reimplemented with electronic circuits,
which will consume much less resources than general purpose quantum computer.

~~~
bnegreve
> efficient quantum algorithms can be reimplemented with electronic circuits,

You can emulate a quantum computer with a classical one, but it takes
exponential time.

If you could emulate them efficiently, quantum computers would just be another
Turing machine, with all the limitations we already know. I think this is the
whole point of quantum computers, they are different from what we already
have.

~~~
lisivka
I talking about analog computing, not about digital computing.

[https://en.wikipedia.org/wiki/Analog_computer](https://en.wikipedia.org/wiki/Analog_computer)

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lutusp
Quote: "Here’s the list of the underlying technologies:

(1) Electromechanical;

(2) Vacuum Tube;

(3) Relay;

(4) Transistors; and

(5) Integrated Circuits."

Surely not in that order? Because Relay = Electromechanical. The "Relay" item
is certainly out of place. In the history of computing devices, relays (and
purely mechanical computing devices like the Difference Engine) predated
vacuum tubes, which predated transistors, which predated integrated circuits.

~~~
unlikelymordant
Perhaps electromechanical is in reference to something like the enigma
machine. Characters light up on a board, but the character that lights up is
chosen by a purely mechanical process that selects the current path. I'm just
speculating.

~~~
lutusp
> Perhaps electromechanical is in reference to something like the enigma
> machine.

Yes, I agree, good example, but that also predates vacuum tubes as
computing/logical elements. So the temporal order is still wrong.

Maybe the author didn't really intend that the list be temporally ordered --
but it seems as though that was the intent.

~~~
dogma1138
I think by relay they are referring to reed switches:
[https://en.m.wikipedia.org/wiki/Reed_relay](https://en.m.wikipedia.org/wiki/Reed_relay)

Which were used for memory and other computing tasks after tubes were already
obsolete.

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realworldview
This, VR and smart 3D television.

Vacuous comment pieces are great for generating and maintaining interest and
pushing understanding and ideas forward. However, reality checks are essential
to avoid this being little more than a sci-if short story, with realistic
considerations.

Delving into why quantum computing may not be useful for implementing PHP 8
would be an interesting article. Encryption is the quantum computing poster
child. What else will it give us?

Only being negative to help us find the positives and promote practical and
realistic understanding of the subject.

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edblarney
For context, check out this 'Science International' video:

[https://www.youtube.com/watch?v=fF8vLUEp29E](https://www.youtube.com/watch?v=fF8vLUEp29E)

If you're of a certain age, you'll remember this series from when you are a
kid, they talked about 'all the future things'. Except almost none of it came
true.

The future is hard to predict.

Maybe they will make some progress in 12-18 months in Quantum, we we are a
long way off from seeing anything working, I believe.

The Crytpo implications alone are pretty crazy.

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asymmetric
_By the time you get to 300 qubits, you’ve got a computer that can do more
“calculations” than there are atoms in the universe._

I don't understand what this means. Last time I checked, the Universe was
infinite.. So what does this claim exactly mean? Because it's not the first
time I've seen it.

~~~
ywain
The author likely meant "observable universe". 2^300 ~= 2*10^90, and it's
estimated that there are around 10^80 atoms in the observable universe[0].

[0]
[https://en.wikipedia.org/wiki/Observable_universe#Matter_con...](https://en.wikipedia.org/wiki/Observable_universe#Matter_content)

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nigrioid
Judging by the sensationalist clickbait articles in the list on the left, I
wouldn't hold my breath for anything that's said here.

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camillomiller
Stop Quantum Supremacy Now!

~~~
realworldview
In Trump's hands...!

~~~
user5994461
Next article: "Making silicon computers great again!"

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Jweb_Guru
Nope.

