I don't think this is entirely accurate. From what I can recall, the case against Landis was from two tests. The first showed that his T/E ratio was well outside the normal ratio for humans. Note that this is different from having elevated testosterone, in fact I believe his testosterone was actually lower than normal. It was just that his epiesterone was WAY lower than normal (these are normally about equal, his ratio was 12/1). As far as I remember this test was somewhat discredited due to shoddy procedures at the lab. The one that stuck was an isotope test which showed that the testosterone in his sample had a different isotope ratio than is found in humans. From this they concluded that it was synthetic and thus upheld the ban. I don't claim to entirely agree with all of their methods or even the results of the test, but I really don't think it's fair to say that he crashed, had a surge of adrenaline and subsequently tested positive.
This is slashdot, so I suppose it should not come as a shock that the summary makes claims that don't stand up to even a casual examination. About 15 seconds on google scholar produces the following paper:
Correa, A.A. and Bonev, S.A. and Galli, G, Carbon under extreme conditions: Phase boundaries and electronic properties from first-principles theory. Proceedings of the National Academy of Sciences of the United States of America.103, 1204 (2006) link to article
The second paragraph of the article in Nature Physics (subscription required) that this story is about mentions at least 11 other papers on theoretical calculations and experiments on the melting of diamond. So no, this is not in fact the first time that the melting of diamond has been studied. Indeed, the linked article itself refers to previous experiments at Sandia National Laboratory that melted diamond, but were unable to accurately determine the temperature and pressure.
This is truly impressive work by some very skilled scientists, but let's discuss it for what it is and not what it isn't.
While this sort of machine is useful (I just built one for quantum Monte Carlo calculations 6 months ago) it is hardly news. NVIDIA has been pushing this sort of machine since the launch of the Tesla. In fact, they have had a parts list on their website for some time telling exactly what is needed to put together a computer with 4 C1060's. This is not even the first commercial offering of this nature, with companies like appro and microway having similar products for at least a year (see nvidia) for a more complete list.
Thanks for the info, I did a quick search to see if it was being commercialized and found nothing. That link showed something that makes me pause though, the receiving coil looks HUGE! I am assuming that to get to a smaller coil they would have to use a higher frequency field which I'm assuming will decrease range. Hmmm. I guess I should just do the math myself and see....
I'm relatively pessimistic about both of the technologies mentioned due to the inherent limitations that they pose (large leakage of radiated power or short range). I'm looking forward to seeing products based on the wireless power idea that came out of the Joannopoulos group at MIT in 2006. The idea was that you can setup an RF wireless power transmitter in such a way that it does not actually transmit any power unless it resonantly couples to a precisely shaped receiver. This way there is little to no leakage and they claimed that the power transfer was quite efficient. I'm sure this was posted to slashdot, but I can't seem to find it. Here's a link to the paper if you are somewhere with access to Science: Science 6 July 2007: Vol. 317. no. 5834, pp. 83 - 86 and here's a link to the press release by the MIT news office (no subscriptions required).
I recently had a chance to see Francois Gygi, one of the principal authors of qbox (http://eslab.ucdavis.edu/) which is a quantum electronic structure code that has set some performance records on the Blue Gene/L at Livermore. He mentioned that the biggest challenge he faced was the very small amount of memory available to each node of the Blue Gene (something like 256Mb). This forced him to put so much emphasis on the internode communications that simply changing the order of the nodes where the data was distributed in the machine (without changing the way the data itself was split) affected performance by over 100%. This will only get worse as the number of cores per board goes from 2 to 4 on the Blue Gene/P. I couldn't find anything in a quick google search, but does someone know what the plans are for the memory on this new machine?
I am one of the unintelligent few who installed a copy of vista business on my laptop at the beginning of the year. I have been using vmware workstation to run linux under windows for about a year now and as such was very interested in VmWare's progress on supporting vista as a host operating system. VmWare 5.5 would run under vista, but only after a lot of tweaking and even then the performance was less than stellar. I enrolled in the 6.0 beta testing program as soon as it was available and I have not been impressed with the product so far. What I have found is that VmWare has fixed most of the nagging issues with User Access Controls etc., but there are still a few major things lacking. The first is that the networking to host OS's seems to disconnect after each suspend without any messages about why or even how to reconnect them. The second seems to be the interaction between vista and VmWare. For whatever reason any time I do a power operation on the guest OS (suspend, restart etc.) my hard disk starts thrashing like crazy and I am unable to use the machine for 2-3 minutes. This is on a laptop with 2Gb of ram that never had these issues under WindowsXP. Additionally, these hard disk thrashing issues happen at random times while I am using the guest OS. Perhaps some of this is due to the debugging that is enabled with the beta builds of VmWare, but I'll certainly be a bit cautious about spending my several hundred dollars on upgrading to Workstation 6.0 given the performance that I have seen so far.
I don't doubt your premise, but I find the way you have stated it perhaps a bit too broad. How can there be freedom of speech if there are no protections at all from the consequences of that speech? As an example, is not locking you up and throwing away the key a consequence that the first amendment was likely seeking to rule out?
It seems to me that apple will resist having wi-fi in the ipod because it would break their grip on the interface to the ipod. They have a great revenue stream with all of the third party gadgets that connect to the dock connector and if they gave the ipod a meaningful wi-fi connection, it would be a lot easier to make such additions without paying a licensing fee to apple. It would be nice though...
I noticed that they called Apple the largest purveyor of DRM technology. I thought that far more DVD's had been sold than songs from iTunes. Is there something I'm missing that makes DVD's free of DRM or is this just a case of Apple having DRM that's not broken too badly? I know that here in the USA it's just as illegal (thanks DMCA) to get around one as the other.
I agree very much with your post, but would just like to point out that all of this really depends on your application. As an example, many high performance applications use the metropolis method to do Monte Carlo, and in that case (as in many other "embarrasingly parallel" applications) the interconnect hardly matters at all.
Not to be overly critical, but in the article it states that soldiers still have the option of mailing their ballots. (this was somewhere around that inane comment that if they were uncomfortable with email voting they could use some other method.)
This year one of the nobel prizes in physics went to Tony Legget who explained experiments over twenty years ago in which Helium 3, when cooled low enough exhibited superfluidity. In this scenario the Helium 3 which is a fermion pairs up much like low Tc cooper pairing (except in a p-wave state). This allows it to flow without resistance in addition to giving it interesting magnetic properties. What I would like to know is how this experiment is different from the experimental work on Helium 3. It seems that both involve pairing of fermion atoms to form bosons, except that somehow in this example there are charge carriers... Does someone have a reference to the article at the preprint archive (or in a journal)?
Off the top of my head I can think of two areas where this could be useful for quantum computing. The first would be as a way to comvert flying qubits (photons) in to stationary qubits. If this could be done, than technology such as quantum repeaters would be possible, therefore allowing for long distance quantum cryptography. The second would be as a single photon source, which would have big applications in optical quantum computing.
The article, however, was very light on specifics. It says that the light exhibits antibunching, yet calls it a laser. My understanding of coherent states was that the probability of sending out two photons was high enough that it causes problems with quantum cryptography (Eve can simply observe one of the flying qubits and let the other one go). So do they envision using this as a single photon source? I haven't had a chance to read the journal article yet, so if someone who has a little more info could clarify I would be quite appreciative.
Many of the posts so far seem to be saying that someone so young should not be responsible for these actions. I wonder what we would say if she were responsible for Blaster?
Re:forces between objects?
on
The Casimir Effect
·
· Score: 3, Informative
I'm pretty sure that the Casimir force was originally "discovered" as a natural consequence of quantum field theory. It was only recently (something like two years ago) that it was first measured by an experiment at Los Alamos. It was very exciting when it was measured because this aspect of quantum field theory predicts that the vacuum of space contains an infinite background energy and that the Casimir force is actually due to the charged plates restricting the wavelenghts of photons which could be created and anhillated by the vacuum. By imposing this boundary condition, the pressure from these photons on the inner surfaces of the plates is less that the pressure on the outer surfaces of the plates and thus the force pushing the plates together.
The best thing about photonics is the absence of (photon) migration, which is a big problem with small trace size electronics (electron migration). (Aside: If a silicon engineer knows better, please correct me.) No migration happens because photons have 0 rest mass, and therefore don't have intertia. This means they are a lot less likely to over shoot the switching mechanism, and maintian signal. This is in addition to thier electrical interference resistance.
Actually photons can still "overshoot" switching devices etc. Photonic Band Gap materials have all of their properties because of they way they exploit the quantum nature of the light. So, just like semiconductors, there is a finite probability that the light will tunnel to another place. The reason that I don't think this will be a problem any time soon is that for the wavelengths of light people are interested in making "photonic circuits" with, the features of the material are so small and at this point difficult to manufacture, that the tunneling barriers are effectively infinite. Once methods are developed for working effectively with arbitrary 3-D fabrication at the precision we are accustomed to in silicon, photon migration will likely become a problem.
Would the RIAA have a claim if the company in question were only to put songs which it's employees owned copies of onto the server? Furthermore, if the company required that employee to put their CD into a vault and restricted the server so that it could only stream the files and indeed only stream them to one person at a time? This would allow more people access to the music, but shouldn't be much different in principle to a library. Just a thought....
Could you please clarify? It sounds like from your balloon analogy that the current "universe" is like the surface of a balloon and that there are other balloons nested inside this balloon. From this you seem to conclude that there are 4 spatial dimentions (presumably three dimensions on the surface of the balloon and then a radial dimension which corresponds to traversing between the universes.) I must have something wrong though, because I have just stated a fallacy. If our universe if like the surface of a balloon, then it has only two spacial dimensions corresponding to radial and axial angles. Where have I gotten off course?
My understanding of semiconductor design is a little shaky, but don't these devices work by localizing a charge somewhere inside them? If that's the case and the device is only the size of 3 atoms, won't it be extremely difficult to localize a charge into that space. Even geting the thing to hold a single electron seems unlikely becuase of the couloumb repulsion, spin orbit coupling, etc that souch a small device would have to overcome.
Also, if they are working with conventional processes, how will they deal with the diffraction and quantum effects of shooting electrons or photons through the mask which they use to create the chips? I'll be very interested to see the details that the article said would be realeased tomorrow, because this promises to be extraordinarily revolutionary physics if they have indeed succeeded in producing transistors this small.
I know this is a bit off topic, but I find it ironic that you are advocating an increase in government spending on NASA (technology in general) and that your.sig is the Kansas state motto. That definitely gave me my chuckle for the day.
Other posters have picked up on the fact that the quantum state of the electron will have to be refreshed to prevent decay and thus data loss. I believe that there will be another fundimental problem with this approach. They are using super-position of wave functions to store the data in the electron, but whenever the data is read back, the wave function will collapse and the data will be lost. For this reason this will probably never be practical for large amounts of static data storage, but has more promise as a ram-type technology.
I'm pretty sure that radio stations pay their fees to things like ASCAP and BMI which redistribute the monies to the artists based on some horrendously complex formula. I don't think the record companies see this money at all.
I think perhaps the pizza delivery metaphor is a bit inappropriate in this case. The original reason for legislation like the rural electrification act is that there is no economic incentive for a utility to serve people in rural areas. The fedral government decided around the great depression that it was important for all americans to have access to basic services, like electricity and telephone access.
When the above poster argues that the government should make high speed internet access available cheaply to all he is merely suggesting that in the next several years, access to the internet will become a basic necessity that should be freely available to all. This is quite unlike pizza delivery which I think we would all agree is not necessary for our basic standard of living.
Finally the person who suggested that rural families should either deal with skyrocketing costs or move "back to civilization" should at least support his arguments a little more. Whether we like it or not, farming is a VITAL part of the american economy. The people who farm in this day and age are not wealthy individuals. As a rule they cannot afford complicated high speed cellular bandwith and certainly not electricity and phone service if the government lifted its regulation. Suggesting that they should just move back to the cities to get these necessities would have dire consequences to our economy. Is it worth paying an extra $.02 per month on your phone bill so some country bumpkin can have electricity? Or would you rather he moved into the city and brought milk prices up to those comparable with liquor. The same thing would happen to the price of bread, cereal, anything with soy in it and most vegetables. I personally would rather subsidize the electricity and not pay later at the grocery store, wouldn't you?
Slashdot Mirror
I don't think this is entirely accurate. From what I can recall, the case against Landis was from two tests. The first showed that his T/E ratio was well outside the normal ratio for humans. Note that this is different from having elevated testosterone, in fact I believe his testosterone was actually lower than normal. It was just that his epiesterone was WAY lower than normal (these are normally about equal, his ratio was 12/1). As far as I remember this test was somewhat discredited due to shoddy procedures at the lab. The one that stuck was an isotope test which showed that the testosterone in his sample had a different isotope ratio than is found in humans. From this they concluded that it was synthetic and thus upheld the ban. I don't claim to entirely agree with all of their methods or even the results of the test, but I really don't think it's fair to say that he crashed, had a surge of adrenaline and subsequently tested positive.
This is slashdot, so I suppose it should not come as a shock that the summary makes claims that don't stand up to even a casual examination. About 15 seconds on google scholar produces the following paper:
Correa, A.A. and Bonev, S.A. and Galli, G, Carbon under extreme conditions: Phase boundaries and electronic properties from first-principles theory. Proceedings of the National Academy of Sciences of the United States of America.103, 1204 (2006)
link to article
The second paragraph of the article in Nature Physics (subscription required) that this story is about mentions at least 11 other papers on theoretical calculations and experiments on the melting of diamond. So no, this is not in fact the first time that the melting of diamond has been studied. Indeed, the linked article itself refers to previous experiments at Sandia National Laboratory that melted diamond, but were unable to accurately determine the temperature and pressure.
This is truly impressive work by some very skilled scientists, but let's discuss it for what it is and not what it isn't.
While this sort of machine is useful (I just built one for quantum Monte Carlo calculations 6 months ago) it is hardly news. NVIDIA has been pushing this sort of machine since the launch of the Tesla. In fact, they have had a parts list on their website for some time telling exactly what is needed to put together a computer with 4 C1060's. This is not even the first commercial offering of this nature, with companies like appro and microway having similar products for at least a year (see nvidia) for a more complete list.
Thanks for the info, I did a quick search to see if it was being commercialized and found nothing. That link showed something that makes me pause though, the receiving coil looks HUGE! I am assuming that to get to a smaller coil they would have to use a higher frequency field which I'm assuming will decrease range. Hmmm. I guess I should just do the math myself and see....
I'm relatively pessimistic about both of the technologies mentioned due to the inherent limitations that they pose (large leakage of radiated power or short range). I'm looking forward to seeing products based on the wireless power idea that came out of the Joannopoulos group at MIT in 2006.
The idea was that you can setup an RF wireless power transmitter in such a way that it does not actually transmit any power unless it resonantly couples to a precisely shaped receiver. This way there is little to no leakage and they claimed that the power transfer was quite efficient. I'm sure this was posted to slashdot, but I can't seem to find it. Here's a link to the paper if you are somewhere with access to Science: Science 6 July 2007: Vol. 317. no. 5834, pp. 83 - 86 and here's a link to the press release by the MIT news office (no subscriptions required).
I recently had a chance to see Francois Gygi, one of the principal authors of qbox (http://eslab.ucdavis.edu/) which is a quantum electronic structure code that has set some performance records on the Blue Gene/L at Livermore. He mentioned that the biggest challenge he faced was the very small amount of memory available to each node of the Blue Gene (something like 256Mb). This forced him to put so much emphasis on the internode communications that simply changing the order of the nodes where the data was distributed in the machine (without changing the way the data itself was split) affected performance by over 100%. This will only get worse as the number of cores per board goes from 2 to 4 on the Blue Gene/P. I couldn't find anything in a quick google search, but does someone know what the plans are for the memory on this new machine?
I am one of the unintelligent few who installed a copy of vista business on my laptop at the beginning of the year. I have been using vmware workstation to run linux under windows for about a year now and as such was very interested in VmWare's progress on supporting vista as a host operating system. VmWare 5.5 would run under vista, but only after a lot of tweaking and even then the performance was less than stellar. I enrolled in the 6.0 beta testing program as soon as it was available and I have not been impressed with the product so far. What I have found is that VmWare has fixed most of the nagging issues with User Access Controls etc., but there are still a few major things lacking. The first is that the networking to host OS's seems to disconnect after each suspend without any messages about why or even how to reconnect them. The second seems to be the interaction between vista and VmWare. For whatever reason any time I do a power operation on the guest OS (suspend, restart etc.) my hard disk starts thrashing like crazy and I am unable to use the machine for 2-3 minutes. This is on a laptop with 2Gb of ram that never had these issues under WindowsXP. Additionally, these hard disk thrashing issues happen at random times while I am using the guest OS. Perhaps some of this is due to the debugging that is enabled with the beta builds of VmWare, but I'll certainly be a bit cautious about spending my several hundred dollars on upgrading to Workstation 6.0 given the performance that I have seen so far.
I don't doubt your premise, but I find the way you have stated it perhaps a bit too broad. How can there be freedom of speech if there are no protections at all from the consequences of that speech? As an example, is not locking you up and throwing away the key a consequence that the first amendment was likely seeking to rule out?
It seems to me that apple will resist having wi-fi in the ipod because it would break their grip on the interface to the ipod. They have a great revenue stream with all of the third party gadgets that connect to the dock connector and if they gave the ipod a meaningful wi-fi connection, it would be a lot easier to make such additions without paying a licensing fee to apple. It would be nice though...
I noticed that they called Apple the largest purveyor of DRM technology. I thought that far more DVD's had been sold than songs from iTunes. Is there something I'm missing that makes DVD's free of DRM or is this just a case of Apple having DRM that's not broken too badly? I know that here in the USA it's just as illegal (thanks DMCA) to get around one as the other.
I agree very much with your post, but would just like to point out that all of this really depends on your application. As an example, many high performance applications use the metropolis method to do Monte Carlo, and in that case (as in many other "embarrasingly parallel" applications) the interconnect hardly matters at all.
I'll believe that information can be sent faster than the speed of light when I get the tipoff from myself in the future.
Not to be overly critical, but in the article it states that soldiers still have the option of mailing their ballots. (this was somewhere around that inane comment that if they were uncomfortable with email voting they could use some other method.)
This year one of the nobel prizes in physics went to Tony Legget who explained experiments over twenty years ago in which Helium 3, when cooled low enough exhibited superfluidity. In this scenario the Helium 3 which is a fermion pairs up much like low Tc cooper pairing (except in a p-wave state). This allows it to flow without resistance in addition to giving it interesting magnetic properties. What I would like to know is how this experiment is different from the experimental work on Helium 3. It seems that both involve pairing of fermion atoms to form bosons, except that somehow in this example there are charge carriers... Does someone have a reference to the article at the preprint archive (or in a journal)?
Off the top of my head I can think of two areas where this could be useful for quantum computing. The first would be as a way to comvert flying qubits (photons) in to stationary qubits. If this could be done, than technology such as quantum repeaters would be possible, therefore allowing for long distance quantum cryptography. The second would be as a single photon source, which would have big applications in optical quantum computing.
The article, however, was very light on specifics. It says that the light exhibits antibunching, yet calls it a laser. My understanding of coherent states was that the probability of sending out two photons was high enough that it causes problems with quantum cryptography (Eve can simply observe one of the flying qubits and let the other one go). So do they envision using this as a single photon source? I haven't had a chance to read the journal article yet, so if someone who has a little more info could clarify I would be quite appreciative.
Many of the posts so far seem to be saying that someone so young should not be responsible for these actions. I wonder what we would say if she were responsible for Blaster?
I'm pretty sure that the Casimir force was originally "discovered" as a natural consequence of quantum field theory. It was only recently (something like two years ago) that it was first measured by an experiment at Los Alamos. It was very exciting when it was measured because this aspect of quantum field theory predicts that the vacuum of space contains an infinite background energy and that the Casimir force is actually due to the charged plates restricting the wavelenghts of photons which could be created and anhillated by the vacuum. By imposing this boundary condition, the pressure from these photons on the inner surfaces of the plates is less that the pressure on the outer surfaces of the plates and thus the force pushing the plates together.
You state:
The best thing about photonics is the absence of (photon) migration, which is a big problem with small trace size electronics (electron migration). (Aside: If a silicon engineer knows better, please correct me.) No migration happens because photons have 0 rest mass, and therefore don't have intertia. This means they are a lot less likely to over shoot the switching mechanism, and maintian signal. This is in addition to thier electrical interference resistance.
Actually photons can still "overshoot" switching devices etc. Photonic Band Gap materials have all of their properties because of they way they exploit the quantum nature of the light. So, just like semiconductors, there is a finite probability that the light will tunnel to another place. The reason that I don't think this will be a problem any time soon is that for the wavelengths of light people are interested in making "photonic circuits" with, the features of the material are so small and at this point difficult to manufacture, that the tunneling barriers are effectively infinite. Once methods are developed for working effectively with arbitrary 3-D fabrication at the precision we are accustomed to in silicon, photon migration will likely become a problem.
Would the RIAA have a claim if the company in question were only to put songs which it's employees owned copies of onto the server? Furthermore, if the company required that employee to put their CD into a vault and restricted the server so that it could only stream the files and indeed only stream them to one person at a time? This would allow more people access to the music, but shouldn't be much different in principle to a library. Just a thought....
Could you please clarify? It sounds like from your balloon analogy that the current "universe" is like the surface of a balloon and that there are other balloons nested inside this balloon. From this you seem to conclude that there are 4 spatial dimentions (presumably three dimensions on the surface of the balloon and then a radial dimension which corresponds to traversing between the universes.) I must have something wrong though, because I have just stated a fallacy. If our universe if like the surface of a balloon, then it has only two spacial dimensions corresponding to radial and axial angles. Where have I gotten off course?
My understanding of semiconductor design is a little shaky, but don't these devices work by localizing a charge somewhere inside them? If that's the case and the device is only the size of 3 atoms, won't it be extremely difficult to localize a charge into that space. Even geting the thing to hold a single electron seems unlikely becuase of the couloumb repulsion, spin orbit coupling, etc that souch a small device would have to overcome.
Also, if they are working with conventional processes, how will they deal with the diffraction and quantum effects of shooting electrons or photons through the mask which they use to create the chips? I'll be very interested to see the details that the article said would be realeased tomorrow, because this promises to be extraordinarily revolutionary physics if they have indeed succeeded in producing transistors this small.
I know this is a bit off topic, but I find it ironic that you are advocating an increase in government spending on NASA (technology in general) and that your .sig is the Kansas state motto. That definitely gave me my chuckle for the day.
Other posters have picked up on the fact that the quantum state of the electron will have to be refreshed to prevent decay and thus data loss. I believe that there will be another fundimental problem with this approach. They are using super-position of wave functions to store the data in the electron, but whenever the data is read back, the wave function will collapse and the data will be lost. For this reason this will probably never be practical for large amounts of static data storage, but has more promise as a ram-type technology.
I'm pretty sure that radio stations pay their fees to things like ASCAP and BMI which redistribute the monies to the artists based on some horrendously complex formula. I don't think the record companies see this money at all.
I think perhaps the pizza delivery metaphor is a bit inappropriate in this case. The original reason for legislation like the rural electrification act is that there is no economic incentive for a utility to serve people in rural areas. The fedral government decided around the great depression that it was important for all americans to have access to basic services, like electricity and telephone access.
When the above poster argues that the government should make high speed internet access available cheaply to all he is merely suggesting that in the next several years, access to the internet will become a basic necessity that should be freely available to all. This is quite unlike pizza delivery which I think we would all agree is not necessary for our basic standard of living.
Finally the person who suggested that rural families should either deal with skyrocketing costs or move "back to civilization" should at least support his arguments a little more. Whether we like it or not, farming is a VITAL part of the american economy. The people who farm in this day and age are not wealthy individuals. As a rule they cannot afford complicated high speed cellular bandwith and certainly not electricity and phone service if the government lifted its regulation. Suggesting that they should just move back to the cities to get these necessities would have dire consequences to our economy. Is it worth paying an extra $.02 per month on your phone bill so some country bumpkin can have electricity? Or would you rather he moved into the city and brought milk prices up to those comparable with liquor. The same thing would happen to the price of bread, cereal, anything with soy in it and most vegetables. I personally would rather subsidize the electricity and not pay later at the grocery store, wouldn't you?