That is completely wrong. The reason why measurement affects reality is because of the No-Cloning Theorem which dictates that quantum information cannot be copied, so the most that you can do is entangle yourself with the particle which creates the perception of a collapsing wave function. This is not philosophy, this is mathematics.

As a physicist, I believe that the many-world interpretation of quantum physics is the best because it is more practical than its competitors.

The first major competitor is the theory that the world is deterministic and its just our lack of knowledge that causes us to perceive a non-deterministic world. The problem with this is that we have no evidence in favor of this proposition and to the extent we have any evidence it is *against* this proposition.

The other major competitor is the theory that the wave function of the whole universe collapses every time we make a measurement. This agrees very well with experiment as long as the person asking the question is the one doing the measurement, but it has a major problem: since wave functions don't collapse unless measured, what counts as a measurement? For example, does collapse only happen when *I* make a measurement? If so, why should I be uniquely privileged? Alternatively, does collapse happen whenever some human being makes a measurement --- that is, if I perform the Schroedinger's cat experiment but with a person instead of a cat inside the box, then has the wave function collapsed even if I never open the box (assuming it is perfectly insulated)?

The advantage of the many-worlds interpretation is that it solves the problem of measurement by *not* treating measurement as being an special-case exception to the rules; it postulates that the wave function of the universe never actually collapses. Given this, how do we make sense of the fact we human beings *do* observe such a collapse? The answer actually appears right in the math: when we demand that a particle in a mix of states tell us which state it is in, it causes us to become entangled with the particle so that a *portion* of the universe splits into two states: one with the particle in the first state and us seeing it in the first state, one with the particle in the second state and us seeing it in the second state, and so on. So from the perspective of each of the observers the wave function has collapsed even though it never did. What happens then if you put an observer in a box and have him or her make a measurement? The answer also appears in the math: although the universe splits inside the box, it does not split outside the box.

This might seem fanciful, but it is something that we can actually test. Although we cannot put human beings in a box for ethical reasons, we can put increasingly large systems in the box that act as "observers" of some particle (by engineering an interaction between the observer and the particle) and then perform interference experiments to determine whether the wave function in the box has collapsed or not. Every such experiment we have performed has shown that the wave function does in fact *not* collapse inside the box but rather splits.

So what is the mathematical difference between being inside the portion of the universe that splits and being outside it? It is simple: if you are outside the portion that splits, then the wave function of the universe can be expressed as a tensor product between you and splitting portion. If you are inside the portion that splits, then this can never be the case.

Thus it turns out that measurement *already falls out of quantum mechanics* in a mathematically rigorous and observer-independent fashion, as long as we are willing to accept that a consequence of this is that from the view of someone external to the universe there is a (mathematically rigorous) sense in which there are multiple copies of you and I within the universe. Sure, if we don't like this consequence we can add a rule that gets rid of it by specifying that the wave-function collapses, but then you have to introduce some arbitrary rule that specified that some macroscopic bodies have the power to cause a collapse but not others. Now in fairness, there do turn out to be mathematically rigorous ways to do this and some of them even provide testable predictions so one of them might be proven correct one day, but there is no evidence that any of them is correct and again all of our experiments to date have indicated that if the experimenter is isolated from the observer than the wave function does not collapse under observation so I am not holding my breath.

In conclusion, speculating about which interpretation of the world is correct is actually not pseudoscience because many of the competing interpretations have quantitative characteristics that we can explore using mathematics and probe using experiments.

Would you please explain why you think that Prolog is powerful for DSL creation? This is an honest question, because the language fascinates me and I would like to experiment using it for a project one day, but I have never run into a situation where it looked to me like writing a program in Prolog would be easier than using some other language+library.

Yes, and for a post complaining about cheating I am mildly annoyed that he himself cheated his way around my "filter all posts made by editor kdawson" setting by submitting his story as a normal user and then getting another editor to post it.

Dear lord, it has already become alive and self-modifying? Someone shut it down before it's too late!

Here is a link to the paper on the arxiv:

http://arxiv.org/abs/1008.2390

Reading through the abstract, I see that a significant feature of this cryptosystem is that it cannot be solved by "strong Fourier sampling", which makes the situation more interesting because it is only a slight exaggeration to say that quantum Fourier transforms are the only trick we know of that lets us get exponential speed-ups in quantum algorithms.

It doesn't apply to this article. The way that one typically breaks a cryptosystem is not by reverse engineering (which is not even meaningful here, given that the algorithm is already completely open), but by finding a clever new way to solve the mathematics underlying the system using less information than the designers of the system had thought was needed.

It is worth noting that solving hidden subgroup problem is a subfield of quantum computing that has been active for a while. Although we can't figure out how to solve it in general, we can solve specific instances of it; for example, I think that factorizing is one such instance.

Thus, I suspect that we will eventually figure out a way to break this encryption. Even if we do, though, these mathematicians still get credit for giving us a new instance of the hidden subgroup problem to try and solve, which may give us additional insight into the extent to which the general problem can be solved by a quantum computer.

As a graduate student, who has just started learning how to write and submit papers, I have the following advice.

First, the submission process is a lot more open then I thought it would be; you create an author account, and then just submit the paper. Your paper then will largely be judged on its merit --- whether it is well written, well-explained, interesting, and brings a worthwhile new idea to the table. So in short, don't be scared off from publishing. :-)

Second, do a lot of background reading before hand so that you can figure out where your idea ties in to what has been done before. This is *very* important, because for your paper to be taken seriously you need to show that you have done your homework to learn what has been done before.

Third, keep in mind that most people who read your paper won't care about the details and will just want to figure out what the big takeaway idea is that they should learn --- the same that you yourself will often find yourself doing when perusing academic papers. So although you should endeavor to explain your ideas clearly and precisely enough that someone can implement your algorithm, you should also have a high-level description that explains the big-picture insight behind your idea.

Finally, part of what makes good papers is that they have a good "story" behind them. They start by talking about what has come before, leading up to the new idea that is being presented in the paper and how it follows from or intentionally diverges from previous work. They then talk about the intuition behind the idea itself to give the reader a high-level understanding of the insight behind it. (Note that this is where most people will stop reading, so you want to make the parts up to this good for their benefit. :-) ) Next they go into the technical details of their idea, in a way that is as pedagogical as possible; at every step they explain not only how something was done, but why it was done in that particular way. Finally, they describe how the idea works out well in practice, and then conclude by reminding the reader about what the significance of the idea is (because by this point if they actually read over the details they probably have forgotten :-) ), and end with an optional (brief) discussion about what future research questions are inspired by your idea.

Good luck, and most importantly --- have fun! :-)

Yes it will. However, it is worth mentioning that this is only one of its three missions, and most likely the main reason that this massive multi-billion dollar project received funding from Congress was so that we could we can understand fusion reactions well enough that we can model the inside of nuclear weapons and not have to test them, seeing as how we don't like testing nuclear weapons anymore.

It is worth mentioning that the mini-star only has enough fuel to burn for a fraction of a second. To make an actual fusion reactor from this technology, one would need to create several of them every second. Also, even making *one* of these things ignite is really, really hard, so if your technology breaks down then your reactor stops creating new mini-stars and simply shuts down.

By "mini-star" they just mean a brief fusion reaction that is expected to last for a fraction of a second --- if for no other reason then there is only a limited amount of fuel available to it.

Also, the way in which many of those involved ultimately intend to use this is not to create a reactor drawing power purely from fusion but rather to create fusion/fission hybrid reactor in which neutrons from the fusion reaction drive fission reactions in nuclear fuel that would not become critical by itself --- i.e., so we can burn things like nuclear waste and thorium. Such a reactor would be intrinsically fail-safe because when fuel pellets stop being dropped into the reactor and ignited by lasers into "mini-stars" (which, again, is something that needs to be done continuously --- several times a second --- since the "mini-stars" burn up all their hydrogen fuel so quickly) then eventually the whole thing shuts down on its own.

In other words, this is completely unlike the ridiculous and highly implausible fusion reactor featured in Spider-Man 2 which had the magic power to sustain itself by eating everything around it --- which, incidentally, is a power that even our own *actual* sun doesn’t come close to having, since it can only burn its limited supply of hydrogen fuel.

No, pointing out flaws in software does not make one a "denier", but talking vaguely about how horrible the software is and how therefore its conclusions are worthless without giving concrete proof in support of this claim does.

(Mind you, having said that, I fully acknowledge that the GP post saying "You fucking deniers are morons, thanks for fucking us all over asshole." was a troll.)

When your critics make it clear through their words and actions that their goal is not so much to find the truth so much as to bring you and your research down, then it isn't surprising when you aren't exactly inclined to help them out in this process. It doesn't even matter if you have the truth on your side; people will be able to make you look bad by selectively picking parts of your results and making it seem like you completely screwed things up, even if you in fact did not.

Besides, the critics already had all of the data that they needed to independently either reproduce or disprove the results, since most of the data was already published elsewhere and they were even pointed to where in response to their FOIA request; they were complaining because they did not receive *exact* data set that was used by the CRU since some of it was owned by another agency and couldn't be released, and they refused to work with anything less than the exact data set even though working with equivalent data sets that were publicly available would have been sufficient for the purpose of validating the results.