As far as I know the Cuban government wanted to exchange this guy for Cuban prisioners kept by the US, the Cuban Five. The US refused.

These Cubans went to the US to disrupt the operations of anti-Castro terrorist organizations based on Miami, and for that they were sentenced to 15 years in jail, the same sentence that befell the American guy.

So I do understand that Cuba wouldn't want to give up on their only bargaining chip to free its agents. It's a sad state of affairs, really. So much could be gained if there were a little bit of goodwill on both sides.

I'm finding quite curious the contrast between the comments that appeared the first time this story was discussed in /. and now. Whereas in the first time the comments were balanced and generally positive, now most comments are violently against it. I wonder what caused this change. Perhaps now that it is clear that they are getting money and have a chance of making a difference the corporate shills have woken up?

I don't owe him an apology. I am a physicist, and my field of expertise is foundations of quantum mechanics. I did not say that this idea is insane as a knee-jerk reaction. I have read his paper, and I've been to a presentation by the men himself.

I find superdeterminism isane because it is too strong a hyphotesis: it can explain any experimental result. It is, therefore, incompatible with the very idea of doing science. Let me give you an example. Suppose that you want to measure some property of a particle, say, the polarization of a photon. In a superdeterministic theory, the photon's state could depend on which basis you chose to do the measurement, so you could conclude nothing at all from the result. Even the idea the a particle has some property independ of your choice of measurement does not apply.

And it's also deeply troubling how he arrived at superdeterminism. He wanted to do a deterministic model of quantum theory, but there is these pesky Bell inequalities tell you it's impossible. So what does he do? Simply assumes superdeterminism to brush off the issue.

It's not as if he was building a superdeterministic model per se, it is just an ad hoc hyphotesis that he added to get rid of Bell inequalities.

This kind of article bothers me immensely. It treats Einstein as the God of Science, and uses the fact the he worked on something as evidence that this idea is no crackpottery. Well, guess what, Einstein also shat, farted, pissed, had bad ideas, and even commited mathematical mistakes.

And one should never evaluate a scientific idea based on who's working on it. The Steady-State model of the universe is not a crackpot idea, simply because it is consistent with the laws of GR and (superficially) consistent with observational evidence. Philosophically, thought, it does seem quite silly, and I myself would never have regarded it as more than a mathematical curiosity, had it not been already falsified when I was born.

A more modern example would be 't Hooft's work on superdeterminisc models for quantum theory. The guy is obviously a genius, but this idea is pure insanity, and it saddens me to see people taking it seriously just because a Nobel prize is working on it.

That was a sarcastic answer to GP; I'm not one of these people, I think Sweden is a great country, and I'm fact gonna visit there in two weeks.

I'm aware that yours is the "correct" definition of socialism, but you should also taking into account that the definition is very much culture-dependent. People in Europe usually refer to Sweden as socialist, and I'm happy to go along, since the old form of socialsm doesn't exist anymore in Europe.

You should do some research on how Cuba was before the revolution. People don't revolt for nothing, you know? Although it's undeniable that today Cuba is quite poor (partly because of their own economic mismanagement, partly because of the US embargo), it is still in a better shape than it was under Fulgencio Batista. At least the people now have universal access to health and education.

Sweden also chose socialism. Look at the shithole it has become.

Come on, Minecraft does not pretend the implement classical physics.

The problem isn't lack of rigour, is that it gives you the wrong intuition. For example, the essential feature that distinguishes superposition from a classical mixture is that there is a basis in which the result of a measurement is deterministic, and from what I have seen this is not the case in the mod.

One way that it could be done: a "superposition" block, that can be prepared in the states |0>, |1>, |+>, or |->. If you look at it vertically, you measure in the Z basis, and if you continue measuring in the Z basis, the result doesn't change. If you then measure in the X basis, it's gonna collapse randomly to either |+> or |->, and it's gonna keep being this one as long as you keep looking at it vertically.

And this gives you also complementarity, which I think is one of the fundamental quantum concepts. The way the "observation" block was implemented simply makes no sense whatsoever. It's just a block that is different depending on the way you look. There is no complementarity between the aspects of the block, or anything to deal with the randomness of the quantum observation.

I don't understand what are you talking about teleportation. It doesn't sound to me very much related to real quantum teleportation. But I think the trouble with teleportation is that it is actually quite boring, and would serve no purpose in a game.

But it would be nice if we had some "quantum interaction" thingie (a CNOT) that would take two "superpositions" in different basis to an entangled state, and with this entangled state we could run the chsh game or ek91 qcrypto protocol.

Well, you could say that doing a PhD in physics is playing such a game, and, sure enough, most physicists have a working intuition on how quantum mechanics work -- more on the level of given a description of a situation, they can tell more or less what will happen without doing the calculatios. Doing that part is not hard at all. Heck, this kind of intuition mathematicians develop about the most abstract and artificial objects.

But on a more fundamental level, I don't think it is possible to develop a good intuition, because our brains process information classically; we need well defined bits to reason about. But it might not even make sense to be able to reason quantumly, as the essential feature would be preserving the superposition of the systems we interact with. But to preserve the superposition is to have no memory of the interaction, so... it would be very weird indeed.

Try to imagine what a quantum computer would feel as it processes quantum information: it can only apply transformations to its information blindly, without ever reading out what its input actually is, until the very end of the calculation -- and even this final measurement only because we, humans, want it, it's perfectly legitimate to never have a final measurement at all.

I am a physicist, but these are only drunken speculations...

At first I was quite excited with the idea that someone was able to use quantum mechanical elements in a game. But of course, they were not able to do this. They just created a mod vaguely inspired by quantum mechanics, that helps to perpetuate the myths so beloved by the lay media.

The video linked just shows a dude running around, nothing very interesting. If you search youtube a bit, you can find videos talking about the mechanics they implemented. I found this one, about the basic elements -- observation, superposition, and entanglement --, and this one, with the extremely exciting title "quantum computers and teleportation".

Of course, what they call observation and superposition have nothing to do with the quantum concepts, they are just blocks that are different depending on which direction you look at them, and the "entanglement" block is just a glorifed telephone. Their quantum computer doesn't seem to do anything besides teleportation, which is Star Trek teleportation instead of quantum teleportation.

Admitedly, these guys set out do to a terribly difficult task: quantum mechanics is a bit subtle, and quite far from games. The only ones I can remember off the top of my mind are the CHSH game, which is about as exciting as tic-tac-toe, and a quantum strategy to cheat at bridge, which requires you to do a nontrivial amount of maths (and is actually unpublished research =).

They have, nevertheless, failed. The mod looks cool as a game, though.

That's the kind of mentality that leads Firefox to shipping with a different interface every version.

This is completely beside the point (although true). The problem is that the voting system allows for such a thing to happen. Ever wondered why no European democracy has a two-party state? Well, they have sane voting laws. First past the post system without runnofs is just insane. Gerrymandering, electoral college, come on. Once the US was an inspiration to every democracy in the world. Now it has become a laughing matter.

As far as I know the Bristol folks do integrated optics, so it is in fact a chip; not as small as a classical chip, but about the size of a fingernail.

As a side note, it makes me sad that such an awesome project had to taint itself with the mention of Google and NASA waste of millions of dollars to D-Wave. What the Bristol people are doing is quantum computing. What D-Wave is doing isn't.

I don't think the analogy holds. Certainly knowing the details of quantum optics is quite labourious, but doing quantum programming is already some kind of quantum mechanics, that does not reference any particular physical system. Just like a Turing Machine uses Boolean algebra, but does not reference any particular machine to implement it.

Also, it's true that the algorithms are described in purely classical terms, but they probably sound like gibberish if you are not familiar with the concepts. As an example, let me describe you one of the simplest quantum algorithms known, the single-qubit version of Deutsch's algorithm, which decides whether a (classical) single-bit function f is such that f(0)=f(1) or f(0) != f(1):

Initialize your qubit in the state |0>
Apply the Hadamard gate to it
Apply the oracle that calculates f to it; it is described by the operator e^(i pi f(0)) |0>1|
Apply the Hadamard gate to it again
Measure in the computational basis.

I don't think it is particularly hard to understand it, though; if you want to do it seriously, there's a quite good book about the subject: it's called "Quantum Computation and Quantum Information", by Michael Nielsen and Isaac Chuang.

Can you elaborate on that? My laymen impression is that prosecutorial discretion allows you to at any time ignore any law you wish. But to ignore a specific law all the time seems a bit of an exaggeration.