The research they're doing will not have applications in energy production.
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.)
RTFA, it does find that they had a keen interest in stonewalling critics. So much for peer review, taking some criticism, and I dunno integrity?
Truth should be easy to defend. There's not much scientific integrity if you have to stifle descent.
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.
(The astute reader can guess my position on the matter of anthropogenic global warming, but the above statement is independent of the scientific truth of the matter.)
Wait... what? If we really can guess your position on the truth of AGW based merely on a completely unrelated statement on the bias of a government agency, then this suggests that your position on AGW is somehow influenced by your opinions of government agencies, which is silly.
The reason why "global warming" was changed to "climate change" was because people were complaining that some parts of the world were getting colder and so it was obviously bunk, when really what was meant was that the global *average* temperature was increasing. So they changed the term to "climate change" in order to prevent this confusion, even though the predictions are exactly the same, but now they are being attacked for having changed their predictions to match the latest cooling trends (which, again, they didn't) as if this proves that you can't trust anything they say!
This goes to show that you just can't win with some people.
> I want to become reasonably informed about global warming, but I don't have time to go get the appropriate degree, and nobody out there is boiling stuff down to layman's terms so I can make a reasonably informed decision.
This page has a bunch of links that do as you ask and try to boil the information down for you:
Pure speculation, but it could be that their goal is to order the window buttons in *increasing* order of their impact on the window, so that the easiest to click button merely resizes the window rather than of taking it away or destroying it. This arguably makes more sense then the OSX interface where the easiest button to click of the three is the one that gets rid of your window.
Actually, time is *not* just another dimension. It is more like an additional dimension to the three spatial dimensions *that takes the value of an imaginary number*.
When you compute the square of a length in space, you take the sum of the squares of the length along each dimension, i.e.
l^2 = x^2 + y^2 + z^2
However, when you compute a length in spacetime in the setting of special relativity, you actually *subtract* the square of the length in time:
l^2 = x^2 + y^2 + z^2 - t^2
(You can put a factor of the speed of light in front of that time length if it makes you feel better about the units.)
Furthermore, the following is a fundamental law of quantum mechanics: Given a system described by a hamiltonian, H, the time evolution operator, U(t), that evolves a state forward "t" units in time is given by
U(t) = e^{itH},
i.e. the (matrix) exponential of *the imaginary number* times the time (in real units) times the hamiltonian.
So in short, time really is different from the spatial dimensions at a very fundamental level; it is not just another spatial dimension that we just so happen to perceive as something different.
Wow, thank you so much! I hadn't even looked at the link until you endorsed it, and it was thoroughly entertaining!!! I was laughing hysterically throughout the entire thing.:-)
Wow, talk about progress! It used to be that if you wanted to see whether someone was a vampire you would have force them into holding a Bible to see if it burns their hands, but now all that you have to do is to bless your cell phone and then use it to send them a holy text!
The fact that something cannot practically be directly measured at a particular precision without creating a black hole does not mean that it does not exist at the desired precision.
This is a nitpick, but technically the world is not stochastic but rather our perception of it is. When you run an experiment where you can't observe what's going on, it evolves in a perfect deterministic manner. Only the act of forcing an experiment that ends in multiple states to pick one of those states introduces the perceived non-determinism.
You are thinking about quantum mechanics backwards. The true things that exist do so in many “classical” states simultaneously, i.e. the true nature of the “particle” is really a wave. We are the quirks in the system because our wave functions are so highly entangled that we perceive the universe as if it were deterministic. When we “measure” a quantity, what we are doing is forcing something that is in many states to tell us which state it is in. However, this is actually a nonsense question because the true thing is not necessarily in any “classical” state. Thus, something weird has to happen.
According to pure quantum mechanics --- that is, independent of which interpretation you choose --- the dictated evolution is for both observer and observee to become entangled so that the observer/observee system exists simultaneously in multiple states, but in a way such that in each state of the full system the observer sees the observee in a different particular classical state. The only problem with this is that things get even weirder when *you* are the observer; at that point, pick whatever interpretation you wish to explain what happens. The fundamental point, though, is that regardless of which interpretation you pick, the perceived non-determinism is inevitable and arises not from a incomplete understanding of the universe but rather from the fact that we are forcing it to answer a question for which there is truly no meaningful answer.
You are mistaken. There is no fundamental limit (at least, according to known theory) on the precision of a measurement of the position. The only limit is on how well you can simultaneously measure the position and the momentum. The "plank length" is nothing more than a convenient choice of units.
Amazingly enough, that phrase really does mean something.:-)
"adiabatic quantum algorithm" = algorithm that works by initializing a quantum system into a ground state and then slowly (== "adiabatically") changing the interactions of the system so that the final ground state contains an encoded version of the solution
"magnetically coupling" = the interactions between the "qubits" in the system are magnetic, which means that they physically want to "line up" (or anti-"line up") with each other just like regular magnets
"superconducting loops" = a conductive loop --- like a loop etched in a semi-conductor --- that has been made so cold that it is superconductive; currents going in a loop create a magnetic field that points through the loop whose direction depends on whether the current is clockwise or counter-clockwise, and the magnetic interactions mean that these "loops" tend to prefer to have their magnetic fields pointing in the same direction (or the opposite direction)
"flux qubits" = a qubit engineered from such a superconducting loop, whose "0" is the magnetic field going one way and whose "1" is the magnetic field going the other way; magnetic field passing through surface == "flux"
"rf-squid" = AC squid instead of DC squid, though I don't know enough to speak more precisely about the difference
a) I consider it highly unlikely that the NSA has a secret quantum computer. All techologies which i know are 15-30 years from a working QC. i would believe if somebody tells me that the NSA has something which is 5 years more advanced, but not much more.
I concur with your assessment on this; I was mostly kidding when I suggested the NSA might have one.
No one, really --- at least, none that I am aware of. Most of the technology is still very much in its infancy, so nobody else is making a big push to turn it into a product yet. Having said that, I suppose it is possible that the NSA has a secret quantum computer and is using it to break our codes even as we speak, though I don't know if that counts as an economic competitor.
The problem with D-Wave’s approach is that it is not clear how well it can scale. Their adiabatic strategy involves starting in the ground state of one physical system, transforming it into another system very slowly ( “adiabatically” == very slowly), and then hoping that they stay in the ground state all the way to the end of the procedure; if they succeed in this, then they can read out the new state and they have the answer that they want.
The problem is that this only works as long as it is hard for the system to bump itself up into an excited state. However, as you attack larger and larger problems, the “energy gap” between the ground state and the first excited state shrinks exponentially with the size of the problem, greatly increasing the probability that you won’t end up with the right answer at the end of the computation.
In order to get around this problem, you need to do two things. First, you need to cool the system down so that its temperature is less than the energy gap. However, D-Wave’s cooling system does not accomplish this --- their temperature is too high. In fact, they freely admit that their temperature is larger than the energy gap, it’s just that they are gambling that in practice they can get away with it.
Second, you need to run the transformation very slowly --- at a speed that is roughly proportionate to the size of the energy gap. This might also turn out to case problems for D-Wave as they start scaling up their system to attack useful problems. Furthermore, although they have demonstrated a case where their computer shows a speedup over classical algorithms, this should be taken with a great of salt because as I understand it they basically applied their algorithm in a case where conditions favored it. (Mind you, that isn’t in itself a bad thing --- it is good to understand the conditions under which an existing quantum computer can ever beat an existing classical computer; given the infancy status of the field, I amazed that this can be done at all!)
So in short: no, D-Wave is not a scam, but they are taking a gamble that certain theoretical problems will not bite them in practice, and most QC researches tend to believe that they will lose this gamble even though we hope that they will win it.
It's fine to offer constructive criticism, and you started out well. However it's difficult to find anything that could be construed as constructive in your second paragraph:
In fairness, I suspect that the GP looking for an argument but was directed to abuse instead!
In fairness, I would not call the OSX way inconsistent so much as just a different paradigm from the way that Linux works. In Linux it is easy to create a new window but slightly more work to find your existing window, and in OSX it is easy to find an existing window for an application but slightly more work to create a new one if the existing one isn't what you wanted.
Although there are times when it annoys me that I have to go to an extra step to create a new terminal window, there are also many times when I am glad to have a somewhat memorized location I can click on to bring up my old terminal window no matter where it is.
You have just described the OSX GUI, for which I have mixed feelings.
On the one hand, it is nice to be able to click on a button and get the application immediately, but on the other hand they have designed things so that you can only Cmd-Tab between *applications*, not windows, and switching to another application raises *all* of its windows, so when working with two applications at once things can get very irritating.
I also never use multiple desktops on OSX, since there isn't a convenient way of switching between windows on the same desktop as switching between applications will very often jump you to a different desktop since that is where the application had first been launched.
PS: Since there are a lot of KDE4 haters on this thread, I just want to chime in and say that I actually really like the new KDE4! I run it on my desktop at work and OSX on my laptop at home, and in many respects I actually consider KDE4 to be prettier and have better usability than OSX.
In fairness, it might be possible that these wands are actually functioning as a *mild* deterrent, if some of the terrorists have been fooled into thinking that the wands will detect their bombs. This is not enough to justify their cost or the foolishness of relying on them alone to detect bombs, but at least it might mean that the wands aren't contributing entirely negative value to those who are using them.
While I am not a fan of Perl, in fairness square brackets are a nearly universal programming language notation for array indexing, and "0..3" is very common mathematical notation meaning "everything between 0 and 3 inclusive."
Slashdot Mirror
The research they're doing will not have applications in energy production.
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.)
RTFA, it does find that they had a keen interest in stonewalling critics. So much for peer review, taking some criticism, and I dunno integrity?
Truth should be easy to defend. There's not much scientific integrity if you have to stifle descent.
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.
(The astute reader can guess my position on the matter of anthropogenic global warming, but the above statement is independent of the scientific truth of the matter.)
Wait... what? If we really can guess your position on the truth of AGW based merely on a completely unrelated statement on the bias of a government agency, then this suggests that your position on AGW is somehow influenced by your opinions of government agencies, which is silly.
The reason why "global warming" was changed to "climate change" was because people were complaining that some parts of the world were getting colder and so it was obviously bunk, when really what was meant was that the global *average* temperature was increasing. So they changed the term to "climate change" in order to prevent this confusion, even though the predictions are exactly the same, but now they are being attacked for having changed their predictions to match the latest cooling trends (which, again, they didn't) as if this proves that you can't trust anything they say!
This goes to show that you just can't win with some people.
> I want to become reasonably informed about global warming, but I don't have time to go get the appropriate degree, and nobody out there is boiling stuff down to layman's terms so I can make a reasonably informed decision.
This page has a bunch of links that do as you ask and try to boil the information down for you:
http://www.realclimate.org/index.php/archives/2007/05/start-here/
Pure speculation, but it could be that their goal is to order the window buttons in *increasing* order of their impact on the window, so that the easiest to click button merely resizes the window rather than of taking it away or destroying it. This arguably makes more sense then the OSX interface where the easiest button to click of the three is the one that gets rid of your window.
Actually, time is *not* just another dimension. It is more like an additional dimension to the three spatial dimensions *that takes the value of an imaginary number*.
When you compute the square of a length in space, you take the sum of the squares of the length along each dimension, i.e.
l^2 = x^2 + y^2 + z^2
However, when you compute a length in spacetime in the setting of special relativity, you actually *subtract* the square of the length in time:
l^2 = x^2 + y^2 + z^2 - t^2
(You can put a factor of the speed of light in front of that time length if it makes you feel better about the units.)
Furthermore, the following is a fundamental law of quantum mechanics: Given a system described by a hamiltonian, H, the time evolution operator, U(t), that evolves a state forward "t" units in time is given by
U(t) = e^{itH},
i.e. the (matrix) exponential of *the imaginary number* times the time (in real units) times the hamiltonian.
So in short, time really is different from the spatial dimensions at a very fundamental level; it is not just another spatial dimension that we just so happen to perceive as something different.
Wow, thank you so much! I hadn't even looked at the link until you endorsed it, and it was thoroughly entertaining!!! I was laughing hysterically throughout the entire thing. :-)
Wow, talk about progress! It used to be that if you wanted to see whether someone was a vampire you would have force them into holding a Bible to see if it burns their hands, but now all that you have to do is to bless your cell phone and then use it to send them a holy text!
The fact that something cannot practically be directly measured at a particular precision without creating a black hole does not mean that it does not exist at the desired precision.
This is a nitpick, but technically the world is not stochastic but rather our perception of it is. When you run an experiment where you can't observe what's going on, it evolves in a perfect deterministic manner. Only the act of forcing an experiment that ends in multiple states to pick one of those states introduces the perceived non-determinism.
You are thinking about quantum mechanics backwards. The true things that exist do so in many “classical” states simultaneously, i.e. the true nature of the “particle” is really a wave. We are the quirks in the system because our wave functions are so highly entangled that we perceive the universe as if it were deterministic. When we “measure” a quantity, what we are doing is forcing something that is in many states to tell us which state it is in. However, this is actually a nonsense question because the true thing is not necessarily in any “classical” state. Thus, something weird has to happen.
According to pure quantum mechanics --- that is, independent of which interpretation you choose --- the dictated evolution is for both observer and observee to become entangled so that the observer/observee system exists simultaneously in multiple states, but in a way such that in each state of the full system the observer sees the observee in a different particular classical state. The only problem with this is that things get even weirder when *you* are the observer; at that point, pick whatever interpretation you wish to explain what happens. The fundamental point, though, is that regardless of which interpretation you pick, the perceived non-determinism is inevitable and arises not from a incomplete understanding of the universe but rather from the fact that we are forcing it to answer a question for which there is truly no meaningful answer.
You are mistaken. There is no fundamental limit (at least, according to known theory) on the precision of a measurement of the position. The only limit is on how well you can simultaneously measure the position and the momentum. The "plank length" is nothing more than a convenient choice of units.
http://en.wikipedia.org/wiki/Planck_length
Amazingly enough, that phrase really does mean something. :-)
"adiabatic quantum algorithm" = algorithm that works by initializing a quantum system into a ground state and then slowly (== "adiabatically") changing the interactions of the system so that the final ground state contains an encoded version of the solution
"magnetically coupling" = the interactions between the "qubits" in the system are magnetic, which means that they physically want to "line up" (or anti-"line up") with each other just like regular magnets
"superconducting loops" = a conductive loop --- like a loop etched in a semi-conductor --- that has been made so cold that it is superconductive; currents going in a loop create a magnetic field that points through the loop whose direction depends on whether the current is clockwise or counter-clockwise, and the magnetic interactions mean that these "loops" tend to prefer to have their magnetic fields pointing in the same direction (or the opposite direction)
"flux qubits" = a qubit engineered from such a superconducting loop, whose "0" is the magnetic field going one way and whose "1" is the magnetic field going the other way; magnetic field passing through surface == "flux"
"rf-squid" = AC squid instead of DC squid, though I don't know enough to speak more precisely about the difference
a) I consider it highly unlikely that the NSA has a secret quantum computer. All techologies which i know are 15-30 years from a working QC. i would believe if somebody tells me that the NSA has something which is 5 years more advanced, but not much more.
I concur with your assessment on this; I was mostly kidding when I suggested the NSA might have one.
No one, really --- at least, none that I am aware of. Most of the technology is still very much in its infancy, so nobody else is making a big push to turn it into a product yet. Having said that, I suppose it is possible that the NSA has a secret quantum computer and is using it to break our codes even as we speak, though I don't know if that counts as an economic competitor.
The problem with D-Wave’s approach is that it is not clear how well it can scale. Their adiabatic strategy involves starting in the ground state of one physical system, transforming it into another system very slowly ( “adiabatically” == very slowly), and then hoping that they stay in the ground state all the way to the end of the procedure; if they succeed in this, then they can read out the new state and they have the answer that they want.
The problem is that this only works as long as it is hard for the system to bump itself up into an excited state. However, as you attack larger and larger problems, the “energy gap” between the ground state and the first excited state shrinks exponentially with the size of the problem, greatly increasing the probability that you won’t end up with the right answer at the end of the computation.
In order to get around this problem, you need to do two things. First, you need to cool the system down so that its temperature is less than the energy gap. However, D-Wave’s cooling system does not accomplish this --- their temperature is too high. In fact, they freely admit that their temperature is larger than the energy gap, it’s just that they are gambling that in practice they can get away with it.
Second, you need to run the transformation very slowly --- at a speed that is roughly proportionate to the size of the energy gap. This might also turn out to case problems for D-Wave as they start scaling up their system to attack useful problems. Furthermore, although they have demonstrated a case where their computer shows a speedup over classical algorithms, this should be taken with a great of salt because as I understand it they basically applied their algorithm in a case where conditions favored it. (Mind you, that isn’t in itself a bad thing --- it is good to understand the conditions under which an existing quantum computer can ever beat an existing classical computer; given the infancy status of the field, I amazed that this can be done at all!)
So in short: no, D-Wave is not a scam, but they are taking a gamble that certain theoretical problems will not bite them in practice, and most QC researches tend to believe that they will lose this gamble even though we hope that they will win it.
It's fine to offer constructive criticism, and you started out well. However it's difficult to find anything that could be construed as constructive in your second paragraph:
In fairness, I suspect that the GP looking for an argument but was directed to abuse instead!
In fairness, I would not call the OSX way inconsistent so much as just a different paradigm from the way that Linux works. In Linux it is easy to create a new window but slightly more work to find your existing window, and in OSX it is easy to find an existing window for an application but slightly more work to create a new one if the existing one isn't what you wanted.
Although there are times when it annoys me that I have to go to an extra step to create a new terminal window, there are also many times when I am glad to have a somewhat memorized location I can click on to bring up my old terminal window no matter where it is.
You have just described the OSX GUI, for which I have mixed feelings.
On the one hand, it is nice to be able to click on a button and get the application immediately, but on the other hand they have designed things so that you can only Cmd-Tab between *applications*, not windows, and switching to another application raises *all* of its windows, so when working with two applications at once things can get very irritating.
I also never use multiple desktops on OSX, since there isn't a convenient way of switching between windows on the same desktop as switching between applications will very often jump you to a different desktop since that is where the application had first been launched.
PS: Since there are a lot of KDE4 haters on this thread, I just want to chime in and say that I actually really like the new KDE4! I run it on my desktop at work and OSX on my laptop at home, and in many respects I actually consider KDE4 to be prettier and have better usability than OSX.
In fairness, it might be possible that these wands are actually functioning as a *mild* deterrent, if some of the terrorists have been fooled into thinking that the wands will detect their bombs. This is not enough to justify their cost or the foolishness of relying on them alone to detect bombs, but at least it might mean that the wands aren't contributing entirely negative value to those who are using them.
While I am not a fan of Perl, in fairness square brackets are a nearly universal programming language notation for array indexing, and "0..3" is very common mathematical notation meaning "everything between 0 and 3 inclusive."