These are by no means comprehensive. There are *thousands* of states of matter, when one uses precise definitions. Metallic, insulating, superconducting, liquid crystals (of so many types), ferromagnetics, anti-ferromagnets, etc. etc.
Whoa, someone should have stopped this track. No, the NP problems are still hard. BUT a bruteforce search of solutions can scale as sqrt(N) instead of N. Admittedly, N still grows horrendously (exponentially) with input size, but if you can get the square root, take it. To re-iterate: yes a dent in NP-complete problems; no, not a different complexity class.
Now, someone (Andreas de Vries, you can check the arxiv) has recently claimed to have solved an NP complete problem in polynomial time using a quantum algorithm; almost everyone would be surprised if it were true, but I haven't seen anyone point out the flaws yet.
Note, I agree that BQP is probably smaller than NP. But have you seen the Andreas de Vries paper on the arxiv? He claims to solve search in log N steps, which solves NP complete problems in polynomially time, and shows that NP is in BQP. (He addresses why the usual proof of Grover's algorithm's optimality in scaling is inapplicable to his algorithm).
As said, I have my doubts, but I haven't had time to check the algorithm myself. I would love some input on the paper from someone who clearly knows what they are talking about.
(1) They never said the results are deterministic. As long as the result is okay 90% of the time, you can just repeat the measurement some number of times. As this gets large, the certainty in your answer can be made arbitrarily large. Just like in current digital computers: maybe a cosmic ray flips a bit, maybe a magnetic field causes a current to curve and arrive late. But the engineers have ensured that these problems occur below some tolerable rate.(one might worry that one has to repeat it so many times that it destroys the efficiency gain, but this is taken into account when analyzing the computational complexity, so it is not a problem).
(2) Some things are deterministic, even in quantu m mechanics. There are times when a particle will have exactly one energy, for example. Without you knowing quantum mechanics, I can't construct an example of this for you, but I assure you it is possible. There is one case that I can argue that I think you will find plausible (and is also related to point (1)): imagine a particle that can be in one of two wells (just holes in the ground if you would like to think of them that way): call them the left state or the right state. Now, apply an elecric field, a really strong one. If the particle is charged (and low in energy), it will move almost entirely to the right well (if that's the direction the electric field "pushes"). Only a very small amount stays in the left state. So one can get arbitrarily deterministic results this way.
The techniques in quantum computing are a little more complicated, but not entirely fundamentally different.
Information cannot go faster than light. End of story. The mysterious "instantaneous influence over arbitrarily long distances" means if you measure a particle's state, and then arbitrarily far away someone else measures another particle's state (which is entangled with the first), his/her result will depend on yours. But you have no control over the outcome of your measurement, so it still appears random to him/her. (And even to tell him/her how the experiment turned out, you will need to send a bit of classical information, at the speed of light.)
I agree with you; if they want people to be interested in helping, they need to provide more frequent updates on the specific results that each user contributes to. Otherwise, they just get (admittedly great) papers published occasionally, and one doesn't really know what, if anything, he/she contributed to the project.
Point 1: If you're referring to the Folding@home at stanford, they indeed publish the findings in scientific journals. They may also share money with corporations. Clearly it's not a simple issue.
Point 2: I agree that is wrong. But I also believe it is a problem with the patent system's details, and not the principle. Where it goes wrong is where something which you didn't discover or aren't responsible for, you control thanks to the patent.
(1) All of the distributed applications that you mention release the results of their research as public scientific publications. Any companies can use the results, but so can anyone else. Subscription to the journals is all that costs money, but generally free "e-prints" are available. All of the distributed applications that you mention are non-profit.
(2) Even if they were patenting the results (which they aren't -- see 1) it is better to have the patented result that one has to pay for than to have nothing. If I have breast cancer, I would rather pay $1000 for a test than be unable to get a test because no company wanted to invest in it.
As a side rant (somewhat related to (2)), you say patents are inhibiting progress. But without the financial incentive that the breast cancer patent generated, the medicine would never have been developed. I'm sorry that so many people only work out of greed, but that's reality at the moment. And it actually works pretty well.
This distributed app (google it) allows a certain group of materials physicists to simulate surface growth at an atomistic level (from quantum mechanics).
It allows them to make detailed predictions about the dynamics of materials, truly a vital task. If we could predict materials properties (hardness, tensile strength, conductivity, surface roughnes, etc.) by playing with composition on a computer -- much cheaper than by experiments, and much more controllable -- then we would have an entirely new realm of engineering. The community that does EON-like simulations do the physics for precisely this; EON does these simulations on a massive scale.
So go run it! (PS I think there are a huge number of similarly parallelizable, and even more important, scientific problems that scientists would release as distributed apps if they saw more people volunteering computer time.)
Who said this is an arbitrary problem? It is a very specific one: converting code in some high-level language into hardware wiring.
You're argument would apply equally well (or equally poorly) to compiling code: "since solving the arbitrary problem is futile, we can't convert a high-level set of instructions into machine code" but as before the problem is not arbitrary. The language --> hardware problem is more difficult than the language --> machine instructions, but not unsurmountably and there is much work being done in the area. I would give references, but everything I know is from people who are working on it personally.
No. ANY property required under particle change (either changing sign like fermions or remaining invariant like bosons) comes from indistinguishable, identical particles. If the particles are distinguishable, there are *no* requirements after a sign change. That is, after interchanging the two particles, the wavefunction could be completely different: not identical, not differing by merely a sign change, but of a completely different functional form.
you must be thinking either of the cosmological constant or some coupling constant I am not aware of. Many coupling constants (those for the strong interaction or quantum electrodynamics, for example) are quite well tested.
you've misunderstood. All this does is simulate the equations of string theory. It could help in making predictions -- the same way that climate simulations help make predictions -- which could be used to falsify string theory, but in no way tests it.
They are not creating superstrings as in fundamental-building-blocks superstrings. Rather, just an emulation of them in BEC's which obey the same equations that string theory says govern strings. So there's nothing to disprove; they are testing real objects against the equations of string theory, they are building a device guaranteed to simulate string theory.
Slashdot Mirror
These are by no means comprehensive. There are *thousands* of states of matter, when one uses precise definitions. Metallic, insulating, superconducting, liquid crystals (of so many types), ferromagnetics, anti-ferromagnets, etc. etc.
i'm so sorry the mods did that to you. maybe not a geek joke, but very funny.
There are 10 kinds of people in this world: those who read binary and those who don't.
Now, someone (Andreas de Vries, you can check the arxiv) has recently claimed to have solved an NP complete problem in polynomial time using a quantum algorithm; almost everyone would be surprised if it were true, but I haven't seen anyone point out the flaws yet.
As said, I have my doubts, but I haven't had time to check the algorithm myself. I would love some input on the paper from someone who clearly knows what they are talking about.
(2) Some things are deterministic, even in quantu m mechanics. There are times when a particle will have exactly one energy, for example. Without you knowing quantum mechanics, I can't construct an example of this for you, but I assure you it is possible. There is one case that I can argue that I think you will find plausible (and is also related to point (1)): imagine a particle that can be in one of two wells (just holes in the ground if you would like to think of them that way): call them the left state or the right state. Now, apply an elecric field, a really strong one. If the particle is charged (and low in energy), it will move almost entirely to the right well (if that's the direction the electric field "pushes"). Only a very small amount stays in the left state. So one can get arbitrarily deterministic results this way.
The techniques in quantum computing are a little more complicated, but not entirely fundamentally different.
Information cannot go faster than light. End of story. The mysterious "instantaneous influence over arbitrarily long distances" means if you measure a particle's state, and then arbitrarily far away someone else measures another particle's state (which is entangled with the first), his/her result will depend on yours. But you have no control over the outcome of your measurement, so it still appears random to him/her. (And even to tell him/her how the experiment turned out, you will need to send a bit of classical information, at the speed of light.)
b/c of a typo, the joke is distinctly unfunny here. see other thread. :)
Not the only "Lara" that has connected linux users to their palms... ;)
Not the only "Lara" that has connected linux users' hands to their palms... ;)
Interesting lineage, by the way.
How old are you: 2 or 3?
I agree with you; if they want people to be interested in helping, they need to provide more frequent updates on the specific results that each user contributes to. Otherwise, they just get (admittedly great) papers published occasionally, and one doesn't really know what, if anything, he/she contributed to the project.
Point 2: I agree that is wrong. But I also believe it is a problem with the patent system's details, and not the principle. Where it goes wrong is where something which you didn't discover or aren't responsible for, you control thanks to the patent.
So I think we're basically in agreement.
(1) All of the distributed applications that you mention release the results of their research as public scientific publications. Any companies can use the results, but so can anyone else. Subscription to the journals is all that costs money, but generally free "e-prints" are available. All of the distributed applications that you mention are non-profit.
(2) Even if they were patenting the results (which they aren't -- see 1) it is better to have the patented result that one has to pay for than to have nothing. If I have breast cancer, I would rather pay $1000 for a test than be unable to get a test because no company wanted to invest in it.
As a side rant (somewhat related to (2)), you say patents are inhibiting progress. But without the financial incentive that the breast cancer patent generated, the medicine would never have been developed. I'm sorry that so many people only work out of greed, but that's reality at the moment. And it actually works pretty well.
It allows them to make detailed predictions about the dynamics of materials, truly a vital task. If we could predict materials properties (hardness, tensile strength, conductivity, surface roughnes, etc.) by playing with composition on a computer -- much cheaper than by experiments, and much more controllable -- then we would have an entirely new realm of engineering. The community that does EON-like simulations do the physics for precisely this; EON does these simulations on a massive scale.
So go run it! (PS I think there are a huge number of similarly parallelizable, and even more important, scientific problems that scientists would release as distributed apps if they saw more people volunteering computer time.)
You're argument would apply equally well (or equally poorly) to compiling code: "since solving the arbitrary problem is futile, we can't convert a high-level set of instructions into machine code" but as before the problem is not arbitrary. The language --> hardware problem is more difficult than the language --> machine instructions, but not unsurmountably and there is much work being done in the area. I would give references, but everything I know is from people who are working on it personally.
And as a result give consistently unreliable, biased answers for even the simplest of numeric tasks. I love progress.
The same reason some of us would do our jobs for free, as we either enjoy them enough or think they are important enough.
I would vote for you.
Its just interchanging the two particles. It's literally the same as if you had taken the two particles and by hand switched their two positions.
No. ANY property required under particle change (either changing sign like fermions or remaining invariant like bosons) comes from indistinguishable, identical particles. If the particles are distinguishable, there are *no* requirements after a sign change. That is, after interchanging the two particles, the wavefunction could be completely different: not identical, not differing by merely a sign change, but of a completely different functional form.
you must be thinking either of the cosmological constant or some coupling constant I am not aware of. Many coupling constants (those for the strong interaction or quantum electrodynamics, for example) are quite well tested.
They are not creating superstrings as in fundamental-building-blocks superstrings. Rather, just an emulation of them in BEC's which obey the same equations that string theory says govern strings. So there's nothing to disprove; they are testing real objects against the equations of string theory, they are building a device guaranteed to simulate string theory.
also, there are many coupling constants...