back to article Bristol boffins announce QUANTUM CLOUD

Ever wanted to fiddle with a quantum computer, but don't have the sort of connections to get you inside a lab? If so, the boffins at Bristol University have just the thing for you: a "quantum cloud"! The wonk-run quantum cloud will give researchers and the general public the chance to book time on a diminutive quantum chip …

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""It's incredibly exciting to think what might be achieved by making this more widely accessible"

Translation: "W built this thing, but we have no clue what to do with it. Ideas, anyone? Anyone?"

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Re: ""It's incredibly exciting to think what might be achieved

Nope. I'm using this chip for an experiment right now.

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WTF?

Generating matter?

"The Bristol chip generates a photon using a blue laser that is split into two red daughter photons"

Splitting one photon into two? Photons having colour? Shurely shome mishtake?

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Re: Shurely shome mishtake?

Er, nope. You can split photons (although perhaps its better to call it conversion) using an optical nonlinearity, as long as you conserve energy. And since the "colour" of a photon depends on its energy (frequency), splitting a high frequency "blue" photon will (can) give you two "red" ones. And with a different setup you can produce photon pairs with mismatched colours.

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Re: Shurely shome mishtake?

The fun thing about photons is that you are never sure about how many there are. Accelerate your reference frame and voilà - instantly more of them.

Back to the article

The Bristol chip generates a photon using a blue laser that is split into two red daughter photons. These photons are prepared as qubits – the quantum equivalent of a digital bit, except these can exist in superposition of states which can be manipulated using electrodes acting as phase shifters that change the speed of the photons via wave guides, which "behave like optical fibres and channel the photons around the chip," the researchers write.

That should probably read

The Bristol chip generates a photon using a blue laser that is split into two red daughter photons. These photons represent a 2-qubit entangled state (and thus you can make the paths of the photons interfere with each other, which would not be possible if the photons were not entangled).

It's not very well explained at all on the Bristol pages ... >:-(

Did I mention you can get Scoot Aaronson's "Quantum Computing since Democritus" in fine bookstores? BUY IT NOW.

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Re: Shurely shome mishtake?

I'll bring even more of a problem to the table, and be even more pedantic...

There never were any "photons" in the first place. It's just a word we use to describe the measurement (interaction) of (in) a Quantum Field. Well, a word and concept we have used for a very long time up till the point we found out about QM.

I'll be happy to be corrected or educated on that point above though, as it's quite interesting learning about these things. :)

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Re: Shurely shome mishtake?

Assuming that I follow what you are saying, would it be more correct to describe that as a 'measured/observed interaction in a Quantum Field'? Are you saying that photons are an intellectul construct of the observer? What does that imply for all the other force/field interaction particles, including the Higgs boson?

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Re: Shurely shome mishtake?

This does not imply all that much.

Ultimately, all these "things" we label are just macroscopic ideas applied to "the layer below". You need to use the mathematical idea to be "closer to the thing in itself".

Consider the position vector of a bullet in a first-person-shooter. There is no bullet. There is a position vector of three IEEE floating point numbers (which exhibit interesting logarithmic granularity). Where is that vector? Not at the bullet's position.

Anyway.

This gave me the thought there are probably plugins for well-known math packages like Matlab which do all this, so:

http://www.quantiki.org/wiki/List_of_QC_simulators

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Re: Shurely shome mishtake?

The photons need to be indistinguishable in order to interfere, entanglement is not necessary!

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Re: Shurely shome mishtake?

The word "photon" and quantum mechanics came at about the same time (1920s), so I don't know what you mean. I admit that my quantum field theory is a little rusty, but I'm not familiar with your point. Do you have a reference so I can read more?

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Sub title

Excellent reference!

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Intriguing.

I don't have a use for it but I suspect for someone this is going to be the perfect way to try out their conceptual understanding of an idea.

Thumbs up for letting the general public a (little) bit closer to one of these things for real.

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ENIAC was the size of a house.

It was a massive machine that you had to book time on. It was a specialised piece of equipment that cost a fortune and wasn't practical for everyone to own. As time went on and techniques were refined and new technology became available you could eventually fit ENIAC's function into something the size of a wrist watch.

This almost looks like history repeating itself. Give it a few more years and we'll be able to get a quantum processor on a PCI card.

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