That's simply 99 gigawatts. "kilowatt-hours per year" is silly. I guess you also don't say your car goes 70 miles per gallon, but your car goes 105 per acre, right? (I hope I got that calculation right; those US units are a true nightmare...)
Well, that's the problem with those popular descriptions. The qubit isn't really in two states at once, but in a single quantum state, which happens to be a so-called superposition of both states. Actually, a single qubit state isn't anything mysterious; if you take an electron spin, and encode "0" as "spin in negative z direction" and "1" as "spin in positive z direction", then one possibility to have "both 0 and 1" is to have the spin in positive x direction (which is just halfway between positive z and negative z direction). It's obvious how you'd measure correct transmission in that case: Just look if the spin still points in positive x direction.
Where quantum mechanics gets complicated is when the qubits get entangled. Then indeed the single qubits individually don't have any defined state. Now, how do you check correct transmission of an entangled state? Well, since quantum operations are always reversible (except for measurements), the simplest way is to just remember how exactly you entangled the qubits, and use the reverse procedure to detangle them again. If the transmission worked correctly, you get your original unentangled states back, which you can easily measure. If that's not an option (e.g. bringing them back together in order to reversably detangle them is not possible or not practicable), you could e.g. make Bell type measurements to check that they are still entangled, or you could use them to quantum-teleport another, known state (which should fail if the state is damaged by the transmission).
Two reasons: * You need a bus, because even with quantum teleportation, you need to transmit (classical) information, * You need a quantum bus, because you need entanglement for quantum communication, and that can only be transmitted through quantum channels (and quantum teleportation consumes entanglement).
Now since you have to transmit quantum states anyway, it would be silly to first transmit unrelated quantum states and then quantum-teleport the actual states using those, instead of just directly moving the real thing.
Note that the situation is different for large-distance transmission, where the errors in quantum transmission might be too high. In that case, it makes sense to send many particles carrying entanglement, which will partly decohere away, but you can distill perfectly entangled pairs from the remaining entanglement in order to transmit your actual quantum information through quantum teleportation using them (which only needs a robust classical channel). Note that even then you need a quantum channel for sending the entanglement, although it may be low-quality (you just have to transmit more entanglement then).
Well, it's not hard to find the bugs in the universe. Indeed, earth is full of them. However I've yet to find out how to exploit a cockroach to get rich...:-)
(I hope you're the kind of slashdotter who reads replies to his comments, so that you answer to this one.)
I usually indeed do read replies, however there's still a chance that when I read it and want to answer that I don't have the time immediately, and then forget it. Well, obviously that's not the case with your comment:-)
There are a lot of things that don't make sense in most interpretations of quantum mechanics. This is what I've read that does make some sense of it all. Does that interpretation not rule out the whole idea of MWI and spooky-action-at-a-distance? (I love that word. Does sum up most I've read on QM at all... sounds like so much medieval alchemy to me.)
Well, I cannot find much meat in that interview (unfortunately it's also hard to extract that meat, because it's intermixed with his views on other topics like AI). It's hard to say anything definitive unless you see the actual interpretation. However there are some points which sound fishy to me: He seems to dismiss everything which goes against his view as "just the crude measurement experiments back then". Well, you may argue away statistical behaviour that way, but you simply cannot argue away the fact that there are indeed localized events. Also he stresses the lasers all the time. Now lasers are coherent light; that's the state which is the most classical-wave-like you can get. Indeed, in an ideal laser, the number of photons isn't even defined. Note that you need single-photon sources to do experiments like quantum teleportation; a conventional laser cannot do that.
However some things he criticises on the Copenhagen interpretation are also not true for MWI. To begin with, in the MWI there are no classical particles at the fundamental level, nor is there any statistical behaviour. Particle-like and statistical behaviour only occur on the observational level.
Of course that's all based on what I got out of that interview. I cannot exclude the possibility that my conclusions are completely wrong. But to tell, I'd have to see the real thing, not just an interview like the one you quoted.
Oh, and BTW in the MWI there's no spooky action at a distance. In MWI, the "instant change of the distant particle" isn't any more mysterious than the "superluminar move of a star from light years on my left to light years on my right" when I turn around 180 degrees.
If there also exists an earlier, GPLv2 version, you can start your fork with that. Of course, if the project started out as GPLv3, you're stuck with it.
It doesn't restrict hardware. You can make your hardware DRMed like hell. You just can't run GPLv3ed software on that DRMed hardware. That's a restriction on the software (don't run it on DRMed hardware).
I mean, they already have your searches(google), your email(gmail) and your documents(google docs), what does it matter?
They somewhat have my searches (but thanks to dynamic IP and me not allowing their cookie, they cannot find out that searches done on different days, and sometimes even the same day, are done by the same person). They don't have my email (I don't use gmail), nor my documents (I keep those on my local hard disk, thank you).
That's what extensions are for. If a third party is involved in a non-obvious way, it always should be an extension. Hopefully it at least is configurable, so that if someone else happens to offer an anti-phishing blacklist, it can use that instead.
More to the point, why would they have to receive the URL (or a hash/portion of it) at all? Is there something which can be done at Google's site which cannot be done locally?
The question is, can they have any kind of effect on our measurement. If they can, they are not parallel worlds. if they can't, they are not part of science.
They have an effect on measurement, because they cause the apparent collapse of the wave function. Without them you have to postulate that collapse separately.
Of course the question of what exists and what doesn't is inherently philosophical. Physics is also compatible with solipsism, in which case the physical laws just govern what I personally observe (because in solipsism that's all there is). Strictly speaking, physics (and any other natural science) is just about describing our observations, and making predictions about future observations. Everything beyond that is philosophy.
However, already from the physical point of view, the MWI is superior: It simply needs less assumptions. It can derive laws which the standard (Copenhagen) interpretation must postulate. That's usually the hallmark of a better theory: You must make less assumptions. For example, Kepler's laws were better than the old Ptolemaic system not because the latter got planet movements wrong, but just because it was simpler: It just needed less parameters. Lorentz aether theory is as good as special relativity in describing special-relativistic experiments, but special relativity is simpler, because it doesn't need an aether. On the latter, note that the aether is not something which is derived, but something additional which is postulated.
Besides, a superpositioned universe and many classical ones are not the same as a concept, which is the only way parallel worlds might exist.
At the fundamental level, there's of course no classical universe. However on the level of our perception thereis an (apparent) classical universe. That one corresponds to a certain projection of the universal wave function. However on the fundamental level, the wave function doesn't distinguish between that projection and certain others which are orthogonal to it. Thus if we take "our" classical universe as real, we must give all the other universes the same status. Of course only if we accept the postulate that the universe is fundamentally quantum-mechanic. Which is a reasonable assumption because it's the best one we currently have (of course that doesn't mean it must be true; after all, before we had quantum mechanics, the most reasonable assumption was that the universe is fundamentally classical).
If you're talking of our observations as a "world" you state that every branch is a world, and in every branch, the universe behaves as if the wave function collapse, isn't it?
Sort of. The "collapse" of the wave function is the change from the pre-measurement branch to one of the post-measurement branches.
Can you clarify what exactly laws A and B are? Sure. Law A is the law describing the time evolution of an unobserved quantum system. That is, basically the Schrödinger equation. Law B is the law describing what happens when you observe something. That is, basically the collapse of the wave function.
First, why the fact that the universe is in a superposition means there are many-worlds? It seems to me as if it means there is one world, but it's not classic.
Yes. But what we see is not that one real world, but "classical projections" of it. And of them, there exist several. Especially measurement results are only relative to each projection, and there exist in general other projections with different results. That is, "parallel worlds".
Second, If we will accept that there are many worlds what does it mean? If we can't interact with them in any way, they don't exist (or so says William of Ockham).
No. William of Ockham didn't say anything at all about existence. He put up a rule for making explanations: Don't add things you don't really need. Now you might claim that you don't need parallel worlds. However, the parallel worlds are not something added, but they are a result of not adding something, where that something is the collapse of the wave function. That is, in standard quantum mechanics you have two sets of rules for the time evolution of states, one to use when you don't look, and another one to use when you look; the MWI throws away the latter set of rules and postulates that there's only one set of rules. Thus it obeys Ockhams Razor by throwing away an obviously unneeded second set of rules present in standard (i.e. Copenhagen) quantum mechanics.
Last, even if there are many worlds, I think the article is misleading as to the difference. They take them as different in the manner of branches of decisions like "will it be an accident or a near miss", instead of using every thing as a branch "will I change into a small giraffe".
If there's a possibility for you to change into a small giraffe, however small the chance, there will be a branch of reality where this happens. If the laws of nature forbid you to change into a small giraffe, there will be no such branch.
We can, of course, go much further, as we are talking of the possible ways of the universe's wave function (which we can't possibly understand without a model greater then the universe) to collapse, which might result in "scenarios" we can't imagine.
Of course the whole point of MWI is to get rid of the collapse...
Well, actually the MWI says the shit (i.e. wave function collapse) does not happen. The "split" is not a creation of new universes, but a change in our view of the universe. At the objective level, no split happens, and no wave function collapses. Instead, we ourselves get entangled with the observed objects (which is a normal result of any interaction in quantum mechanics). That interaction causes a "split" in the observed world, due to the fact that we ourselves, as observers, are part of it. We observe "shit happening", where no shit actually happens. Since in reality there's no collapse happening, all possibilities are still there, and therefore in a "parallel world" (which is just another projection of the same reality) a "parallel I" must have observed the other result.
Now, which theory is simpler:
Theory 1: As long as we don't look, everything follows law A, but as soon as we look, shit happens, and we have to apply law B. Theory 2: Everything follows law A, all of the time. The true reason why law B seems to apply is that law A also applies to us.
Theory 1 is the standard Copenhagen interpretation. Theory 2 is the MWI.
Well, it would be interesting what the result actually was!
What would indeed be interesting would be a proof of the actual probabilities: That's the one piece still missing in the MWI. Of course you can postulate them, just as the Copenhagen interpretation does. But that's not really satisfying.
In short: By construction, you can explain that for a measurement the world will "split up" into two worlds (actually it's not a physical split-up, but more of a logical one; the universe doesn't double, it's just a change of the branch you see). However there's to my knowledge not yet a satisfactory explanation of why we observe them with exactly the probabilities we do (e.g. why do we find ourselves four times as often in "branch A" than in "branch B" if the coefficient of "branch A" was twice as large in our previous branch?)
Unfortunately the article doesn't provide a link to the actual work (or at least some more scientific source about it), so it's hard to say what it actually is about.
Why do you think a C++ programmer has to focus at low level shifts, memory storage, string management, etc? Maybe you are not aware that there's a standard library which liberates you from those needs?
The problem, of course, is that the computer cannot do it automagically. You can leak memory in a GC language just as easily. The only difference is what causes the memory leak: In non-GC languages it's forgetting to use free(), in GC languages it's forgetting to null every reference to that memory (or at least every reference which isn't itself in unreferenced objects).
The problem GC solves is not memory leaks. The problem it solves are dangling pointers/references (i.e. if you have a non-null reference, with GC you are guaranteed it points to a valid object, while in non-GC languages it might point to a freed object, or even into some other object allocated later into the same memory).
Slashdot Mirror
So how do you multiply using a paperback Roget's Thesaurus?
One license to rule them all
and in the darkness bind them.
That's simply 99 gigawatts. "kilowatt-hours per year" is silly. I guess you also don't say your car goes 70 miles per gallon, but your car goes 105 per acre, right?
(I hope I got that calculation right; those US units are a true nightmare
Well, that's the problem with those popular descriptions. The qubit isn't really in two states at once, but in a single quantum state, which happens to be a so-called superposition of both states. Actually, a single qubit state isn't anything mysterious; if you take an electron spin, and encode "0" as "spin in negative z direction" and "1" as "spin in positive z direction", then one possibility to have "both 0 and 1" is to have the spin in positive x direction (which is just halfway between positive z and negative z direction). It's obvious how you'd measure correct transmission in that case: Just look if the spin still points in positive x direction.
Where quantum mechanics gets complicated is when the qubits get entangled. Then indeed the single qubits individually don't have any defined state. Now, how do you check correct transmission of an entangled state? Well, since quantum operations are always reversible (except for measurements), the simplest way is to just remember how exactly you entangled the qubits, and use the reverse procedure to detangle them again. If the transmission worked correctly, you get your original unentangled states back, which you can easily measure. If that's not an option (e.g. bringing them back together in order to reversably detangle them is not possible or not practicable), you could e.g. make Bell type measurements to check that they are still entangled, or you could use them to quantum-teleport another, known state (which should fail if the state is damaged by the transmission).
Two reasons:
* You need a bus, because even with quantum teleportation, you need to transmit (classical) information,
* You need a quantum bus, because you need entanglement for quantum communication, and that can only be transmitted through quantum channels (and quantum teleportation consumes entanglement).
Now since you have to transmit quantum states anyway, it would be silly to first transmit unrelated quantum states and then quantum-teleport the actual states using those, instead of just directly moving the real thing.
Note that the situation is different for large-distance transmission, where the errors in quantum transmission might be too high. In that case, it makes sense to send many particles carrying entanglement, which will partly decohere away, but you can distill perfectly entangled pairs from the remaining entanglement in order to transmit your actual quantum information through quantum teleportation using them (which only needs a robust classical channel). Note that even then you need a quantum channel for sending the entanglement, although it may be low-quality (you just have to transmit more entanglement then).
Well, it's not hard to find the bugs in the universe. Indeed, earth is full of them. However I've yet to find out how to exploit a cockroach to get rich ... :-)
I usually indeed do read replies, however there's still a chance that when I read it and want to answer that I don't have the time immediately, and then forget it. Well, obviously that's not the case with your comment
Well, I cannot find much meat in that interview (unfortunately it's also hard to extract that meat, because it's intermixed with his views on other topics like AI). It's hard to say anything definitive unless you see the actual interpretation. However there are some points which sound fishy to me: He seems to dismiss everything which goes against his view as "just the crude measurement experiments back then". Well, you may argue away statistical behaviour that way, but you simply cannot argue away the fact that there are indeed localized events. Also he stresses the lasers all the time. Now lasers are coherent light; that's the state which is the most classical-wave-like you can get. Indeed, in an ideal laser, the number of photons isn't even defined. Note that you need single-photon sources to do experiments like quantum teleportation; a conventional laser cannot do that.
However some things he criticises on the Copenhagen interpretation are also not true for MWI. To begin with, in the MWI there are no classical particles at the fundamental level, nor is there any statistical behaviour. Particle-like and statistical behaviour only occur on the observational level.
Of course that's all based on what I got out of that interview. I cannot exclude the possibility that my conclusions are completely wrong. But to tell, I'd have to see the real thing, not just an interview like the one you quoted.
Oh, and BTW in the MWI there's no spooky action at a distance. In MWI, the "instant change of the distant particle" isn't any more mysterious than the "superluminar move of a star from light years on my left to light years on my right" when I turn around 180 degrees.
If there also exists an earlier, GPLv2 version, you can start your fork with that. Of course, if the project started out as GPLv3, you're stuck with it.
It doesn't restrict hardware. You can make your hardware DRMed like hell. You just can't run GPLv3ed software on that DRMed hardware. That's a restriction on the software (don't run it on DRMed hardware).
They somewhat have my searches (but thanks to dynamic IP and me not allowing their cookie, they cannot find out that searches done on different days, and sometimes even the same day, are done by the same person). They don't have my email (I don't use gmail), nor my documents (I keep those on my local hard disk, thank you).
That's what extensions are for. If a third party is involved in a non-obvious way, it always should be an extension. Hopefully it at least is configurable, so that if someone else happens to offer an anti-phishing blacklist, it can use that instead.
More to the point, why would they have to receive the URL (or a hash/portion of it) at all? Is there something which can be done at Google's site which cannot be done locally?
They have an effect on measurement, because they cause the apparent collapse of the wave function. Without them you have to postulate that collapse separately.
Of course the question of what exists and what doesn't is inherently philosophical. Physics is also compatible with solipsism, in which case the physical laws just govern what I personally observe (because in solipsism that's all there is). Strictly speaking, physics (and any other natural science) is just about describing our observations, and making predictions about future observations. Everything beyond that is philosophy.
However, already from the physical point of view, the MWI is superior: It simply needs less assumptions. It can derive laws which the standard (Copenhagen) interpretation must postulate. That's usually the hallmark of a better theory: You must make less assumptions. For example, Kepler's laws were better than the old Ptolemaic system not because the latter got planet movements wrong, but just because it was simpler: It just needed less parameters. Lorentz aether theory is as good as special relativity in describing special-relativistic experiments, but special relativity is simpler, because it doesn't need an aether. On the latter, note that the aether is not something which is derived, but something additional which is postulated.
At the fundamental level, there's of course no classical universe. However on the level of our perception thereis an (apparent) classical universe. That one corresponds to a certain projection of the universal wave function. However on the fundamental level, the wave function doesn't distinguish between that projection and certain others which are orthogonal to it. Thus if we take "our" classical universe as real, we must give all the other universes the same status. Of course only if we accept the postulate that the universe is fundamentally quantum-mechanic. Which is a reasonable assumption because it's the best one we currently have (of course that doesn't mean it must be true; after all, before we had quantum mechanics, the most reasonable assumption was that the universe is fundamentally classical).
Sort of. The "collapse" of the wave function is the change from the pre-measurement branch to one of the post-measurement branches.
Law A is the law describing the time evolution of an unobserved quantum system. That is, basically the Schrödinger equation.
Law B is the law describing what happens when you observe something. That is, basically the collapse of the wave function.
If you are a human like I am, why do I only experience my experiences and not yours?
Yes. But what we see is not that one real world, but "classical projections" of it. And of them, there exist several. Especially measurement results are only relative to each projection, and there exist in general other projections with different results. That is, "parallel worlds".
No. William of Ockham didn't say anything at all about existence. He put up a rule for making explanations: Don't add things you don't really need. Now you might claim that you don't need parallel worlds. However, the parallel worlds are not something added, but they are a result of not adding something, where that something is the collapse of the wave function. That is, in standard quantum mechanics you have two sets of rules for the time evolution of states, one to use when you don't look, and another one to use when you look; the MWI throws away the latter set of rules and postulates that there's only one set of rules. Thus it obeys Ockhams Razor by throwing away an obviously unneeded second set of rules present in standard (i.e. Copenhagen) quantum mechanics.
If there's a possibility for you to change into a small giraffe, however small the chance, there will be a branch of reality where this happens. If the laws of nature forbid you to change into a small giraffe, there will be no such branch.
Of course the whole point of MWI is to get rid of the collapse
No, but it was discovered in yet another universe. Unfortunately they are still looking for the answer there.
You mean, the truly fundamental particle of our universe is the goatseon?
Well, actually the MWI says the shit (i.e. wave function collapse) does not happen. The "split" is not a creation of new universes, but a change in our view of the universe. At the objective level, no split happens, and no wave function collapses. Instead, we ourselves get entangled with the observed objects (which is a normal result of any interaction in quantum mechanics). That interaction causes a "split" in the observed world, due to the fact that we ourselves, as observers, are part of it. We observe "shit happening", where no shit actually happens. Since in reality there's no collapse happening, all possibilities are still there, and therefore in a "parallel world" (which is just another projection of the same reality) a "parallel I" must have observed the other result.
Now, which theory is simpler:
Theory 1: As long as we don't look, everything follows law A, but as soon as we look, shit happens, and we have to apply law B.
Theory 2: Everything follows law A, all of the time. The true reason why law B seems to apply is that law A also applies to us.
Theory 1 is the standard Copenhagen interpretation. Theory 2 is the MWI.
Well, it would be interesting what the result actually was!
What would indeed be interesting would be a proof of the actual probabilities: That's the one piece still missing in the MWI. Of course you can postulate them, just as the Copenhagen interpretation does. But that's not really satisfying.
In short: By construction, you can explain that for a measurement the world will "split up" into two worlds (actually it's not a physical split-up, but more of a logical one; the universe doesn't double, it's just a change of the branch you see). However there's to my knowledge not yet a satisfactory explanation of why we observe them with exactly the probabilities we do (e.g. why do we find ourselves four times as often in "branch A" than in "branch B" if the coefficient of "branch A" was twice as large in our previous branch?)
Unfortunately the article doesn't provide a link to the actual work (or at least some more scientific source about it), so it's hard to say what it actually is about.
Why do you think a C++ programmer has to focus at low level shifts, memory storage, string management, etc? Maybe you are not aware that there's a standard library which liberates you from those needs?
The problem, of course, is that the computer cannot do it automagically. You can leak memory in a GC language just as easily. The only difference is what causes the memory leak: In non-GC languages it's forgetting to use free(), in GC languages it's forgetting to null every reference to that memory (or at least every reference which isn't itself in unreferenced objects).
The problem GC solves is not memory leaks. The problem it solves are dangling pointers/references (i.e. if you have a non-null reference, with GC you are guaranteed it points to a valid object, while in non-GC languages it might point to a freed object, or even into some other object allocated later into the same memory).
You mean, if a program is written for Windows, it only needs what the vast majority of Linux distributions have in common?