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Comment by dyeje | Hacker News Reader

Stop reading after the second paragraph, quantum computing isn't some magic wand you wave at problems to make them disappear. It's simply a new way of approaching them, and it requires algorithms designed to take advantage of this new approach to computing to solve said problems.

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Those approaches are increasingly well-studied and a lot of them (Grover's algorithm, anyone?) look an awful lot like magic.

(For people who don't want to look that up, Grover's algorithm does searches on unsorted databases in root-n time, that is, in fewer operations than would be required to inspect every element of the database.)

Grover's algorithm does indeed look rather like magic, but even better is the geometrical proof - WP's description looks good at a quick skim. In my (fairly limited) experience, this sort of geometrical thinking is the best way to understand quantum algorithms intuitively.

Although Grover's algorithm is extremely impressive...it's a probabilistic algorithm, which means that the result is not guaranteed, but very likely. And the likelihood can be increased by running the algorithm more than once.

The likelihood increases exponentially because each time you run the algorithm it's independent of the previous times. Even if it's only 75% sure, you only need to run it a few dozen times before it's more likely for there to be a hardware fault in your display giving you the wrong answer.

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They probably have a dilution refrigerator. It's a pretty standard piece of equipment, and can achieve millikelvin level temperatures, far lower than the 3 Kelvin microwave background.

http://en.wikipedia.org/wiki/Dilution_refrigerator

There are other, more sophisticated methods of cooling, which can go even lower in temperature.

Back when I was an undergrad at MIT I was a solder monkey for a group that used a dilution refrigerator with a very similar sort of setup, also trying to use current in niobium loops as qbits. However, IIRC we were only able to reach temperatures in the 100mK range, whereas the article claims this group is using temperatures less than 1mK. So I think they would probably have to be using something on top of the dilution refrigerator to get that low.

http://en.wikipedia.org/wiki/Magnetic_refrigeration

Dilution refrigerators have their limits, especially when you're trying to cool a complex experiment with a lot of wires and fibers going into it (they all bring in heat). I've seen magnetic refrig units stuck inside of helium cryostats to give them the extra oomph to get such experiments down to millikelvin levels.

>I doubt it.

Everyone is pointing out that you're incorrect, but can I just ask why this particular line would have caused you to dismiss the whole article, even in the event you were right? It's such a pointless statement to get caught up on. This obviously isn't a research paper but there were some interesting ideas to us not familiar with the history of D-Wave. Why the dismissive attitude?

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> I can't be incorrect. I just expressed an opinion.

http://lesswrong.com/

i'm curious why you dismiss it on this. won't the minimum in the "natural universe" be ~2.7K (the background temperature)? while they seem to be a few thousandths of a K from zero, if i understand the text right.

your post was pretty strong / dismissive, so i'm wondering what your (presumably powerful) argument is. what other systems in the universe are "naturally" in a quantum ground state?

There are some places in the "natural universe" that are colder than the CMB. That's because they aren't in equilibrium:

http://en.wikipedia.org/wiki/Absolute_zero#Very_low_temperat...

thanks, i was wondering if there was something like that, but couldn't imagine how it would work (i deleted my other answer earlier because it seemed to all be getting a bit unpleasant; i still think that sentence from the article is pretty inoffensive).

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>Therefore, the statement suggests (with certainty) that there are no intelligent/scientific aliens capable of creating lower temperatures. I take issue with that interpretation.

Yes I'm certain that is what the author is trying to convey. I suggest you re-read the article replacing the line that offended you with "This computer is kept in a very cold place".

>In short, the statement is pompous, insulting and almost certainly incorrect.

The evidence is on his side. You just derided the author for his level of certainty, then suggested he's almost certainly wrong because aliens might exist.

It's not as stupid as it seems. Due to the cosmic microwave background, the equilibrium temperature far from other natural radiation sources is about 3K. But, as we don't know the temperatures in the whole universe and there are natural processes that can cool things below their equilibrium temperature, they should have said "... anywhere in the known natural universe".

The black-body temperature of the background radiation of the universe is about 3K. That means achieving a lower temperature requires an active heat pump.

Also, the link in the GP post that contains proof of a world government run by an artificially intelligent quantum computer has no place on Hacker News. Keep your awe inspiring, jaw dropping news with wide reaching social, moral, and technological implications to yourself!

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