Theorist with publications in dark matter here. This aspect of dark matter is not something new or a "mystery" but something that has been assumed for quite a long time. The alternative to this, "self interacting dark matter" is not entirely ruled out by observatins and explains some issues like the core-cusp problem but it's generally disfavored.
This is really old news (at least in the particle physics cycle) and over a 100 papers have been written about this already. This is one of many papers that points out serious problems with a dark matter interpretation for this signal http://arxiv.org/abs/1408.1699 and here's a less technical blog post discussing the issues http://resonaances.blogspot.co... .
I'm sick of pop-sci websites peddling stuff that particle physicists have already moved on from as the "latest exciting discovery"
Both CMS and ATLAS are seeing bumps in certain Higgs channels around 125 GeV. While the bumps aren't big enough to be press-release worthy (2-3 sigma), a lot of particle physicists think that this is it. There will be an announcement on Dec 13th, and from now on it'll just be a matter of waiting till the bumps are 5 sigma and we can say for sure sure.
Ughh. Pseudo-scientific pop-physics mumbo jumbo. I suggest working through Griffiths or some other elementary QM book as a cure for pop-QM induced retardation.
A study, with so much bluster, and they studied just 94 people. Chuck a couple of zeros on that, then perhaps you have the makings of a worthwhile study and not just an anecdote.
Ugh. Not another math illiterate person complaining about the sample size. For the last time, your intuitive notions of statistics are worthless. The gamer study had a lot of people repeating this stupid objection too.
I am increasingly sick of these kinds of studies that use a sample pool so small as to be statistically irrelevant.
No, it's just that your intuitive ideas of what kind of sample size is statistically relevant are invalid. I am sick of how many people keep saying this even though it was addressed in an earlier post http://games.slashdot.org/comments.pl?sid=1341207&cid=29120539.
Also, the complaints about the sample size being restricted to Seattle are probably unwarranted. The sample size is large enough to provide a 95% confidence level for a reasonably small interval, and it would be highly unusual for such a general result that's true in Seattle to be significantly different for other cities.
It would imply that there was some confounding variable that's exclusive to Seattle that modifies the characteristics of gamers, which is an absurd assumption, and the only reason you would think so without other evidence is if you just didn't like the results of the study.
When people say evolution they don't just mean descent with modification, they mean the hypothesis that descent with modification (and other little things perhaps) is responsible for all the various species, and that this is how they descended from a common (and probably) single ancestor. It it this hypothesis that does not make (sufficiently) falsifiable predictions.
Descent with variation is rather trivial and was known before and independent of Darwinian evolution. Anyone who breeds anything knows this.
The Maldacena duality can't be used to 'make predictions' with a string theory, its just a correspondence between a string theory and a conformal field theory. It's useful because sometimes calculations which are hard in a CFT can be made in the corresponding string theory which is sometimes easier (or vice versa). It cannot be used to support the physical validity of some string theory.
when your alternative is wage parity with taxi drivers, not such a bad choice. Rail on you rebel you.
Which taxi driver makes over 100K? He is a tenured professor. The point of tenure is that you can say what you think is right without being worried about your salary/livelihood.
Apparently the use of the term 'teleportation' is causing a lot of confusion. In QM, two particles that have identical states (quantum numbers) are considered indistinguishable; if they were switched, you wouldn't know. TFA describes a process that allows an entire state to be transferred instantaneously from one particle (or system) to another, and since in QM they are the same, the particle has been 'teleported'. There is nothing superluminal here, since before the state can be transferred you have to send some information across at kosher speeds.
They know it was entangled because they prepared the state way. For example, if you have a spin zero particle that splits up into two particles, and you measure one as spin up, the other must be necessarily spin down, no matter how far away it is, because of the conservation of angular momentum. Or you can think of a neutral particle splitting into positive and negative ones. So I guess it is ultimately the consequence of some conservation law.
What we have is that classical mechanics is a particular approximation of general relativity, at one end of the scale, and of quantum mechanics, at the other.
Not quite, they describe different things, so you can put them on the same scale. Classical mechanics is a framework for describing the dynamics of a system once you specify the forces. QM is a different framework. But GR is a theory for describing a particular force, gravity.
A wonderful example iirc is the spinning top. In classical mechanics, the top cannot be solved exactly. But in general relativity, the top can be solved exactly in about one page
This doesn't make any sense IMO, unless you can come up with something to back it up. If you mean the precession of a top in the presence of gravity, then sure it can be solved analytically in classical mechanics, but the general two body problem has no analytical solution in GR, and I doubt the restriction to a top simplifies it enough to allow a closed form solution. But I can give you valid examples that suggest the opposite. In classical mechanics, the dynamics under a linear potential (constant force) is very simple: constant acceleration in one direction. But try solving that in quantum mechanics, and what you get are hideous Airy functions to describe the position of the particle.
The designer, then, still has the last laugh, until there is a TOE, if there ever is.
Not even then. I don't know what it means among laypeople, but for a physicist TOE means a quantum field theory that describes gravity, electroweak and strong force. I can guarantee that we will have such a theory in 100 years, and probably a lot less. I can also guarantee that this TOE will eventually be superseded by a more accurate theory.
it is interesting to note that the universe is mainly built out of second order laws. This means that in many cases there are a small number of poles or zeros that can control macroscopic behaviour and often analytic solutions exist. This would be how a designer would do it.
Nope. It is just that scientists use simple models like harmonic oscillator for most systems, simply because they are easy to solve. That doesn't mean that the universe is 'built' from second order laws. The rest of your post is also similar misinterpretations of QM, optics etc
IMHO everyone seems to have missed the most glaring flaw in the study. 140 countries that 'practice polygamy'? Really? I strongly doubt that there are 140 countries where the number of polygamists is statistically significant and is large enough to cause a measurable effect on a property of the average male. And only 49 'mostly monogamous' countries? Rubbish.
The problem seems to be the 'monogamy scale' mentioned in the article. Perhaps they considered every country where polygamy in some form is legal as ones that 'practice polygamy'. For example in India, polygamy is legal (only) for Muslims, but there are so few Muslims that practice it that it cannot possibly have any effect on the average male. So this correlation observed among countries that 'practice polygamy' (which in reality just have a tiny causally insignificant number of polygamists) is probably just noise.
Not all the axioms are set in stone. It's possible that special relativity could be violated. That's pretty outlandish, but maybe even a small violation would break the theorem. So if some future theory is only approximately Lorentz covariant this theorem may not apply.
http://en.wikipedia.org/wiki/Lorentz_invariance#Lorentz_violation
Also, entanglement only lasts for one wave collapse, but it seems their thought experiment involves multiple collapses. I haven't finished reading the paper yet so I'm not sure if this affects the conclusion.
I don't care much for fluid mechanics, I was just miffed that we only did Lagrangian/Hamiltonian dynamics for systems of discrete particles (and that is all there is in M&T). That semester I was starting some independent study on QFT (well I was just looking at rel. QM and classical field theory at that point) so it really would've helped if we had generalized to fields instead of just discrete/finite particles. We spent a lot more time on boring Newtonian crap instead (who wants to study stupid Newtonian gravity, even if it is in-depth, their junior year?), which I blame on the content of the book. The rest of the class actually did very poorly in the course; but that is what happens when you ask too little of students. It was so boring I missed 90% of the lectures.
Thus: an M&T based class mech course certainly does not cater to an advanced undergraduate.
Haha. Marion and Thornton is an *excellent* advanced-undergraduate text for classical mechanics. For that level of student, you really can't go wrong with it.
Bullcrap. My undergrad mechanics course was based on Marion and Thornton, and I was disappointed with how little we learned of variational methods and hamiltonian dynamics. And of course, there is no field mechanics AT ALL. Advanced undergraduate my ass.
I only meant that he will be ready for Hartle if he has a general idea of field mechanics, and he doesn't have to put off reading it until he is thoroughly done with Goldstein, which will take quite a while.
Do NOT use the Feynman lectures as a starting point. They are fun to read and will give you a lot of insight if you already know what he is talking about, but I don't know anyone who learned intro physics for the first time from them. I tried it myself in the 11th/12th grade, and didn't get very far.
I would suggest you try books that are somewhere between upper level undergrad and beginning grad level. The main obstacle undergrads face while reading this books is not having the requisite math background; but this should not be a problem for you. So for class mech, use Goldstein. For QM, Sakurai's Modern QM. For EM, use Griffiths, I don't think you should jump into Jackson just yet. For thermo, Schroeder. Supplement all of these with Boas' Mathematical Methods, if there is any math you need to review or learn. After you've skimmed through Goldstein, you might also wanna try Hartle's Gravity, this will probably be the most useful for astrophysics.
Slashdot Mirror
Incorrect. Abstract mathematical objects are not "encoded within the observable universe"
Theorist with publications in dark matter here. This aspect of dark matter is not something new or a "mystery" but something that has been assumed for quite a long time. The alternative to this, "self interacting dark matter" is not entirely ruled out by observatins and explains some issues like the core-cusp problem but it's generally disfavored.
This is really old news (at least in the particle physics cycle) and over a 100 papers have been written about this already. This is one of many papers that points out serious problems with a dark matter interpretation for this signal http://arxiv.org/abs/1408.1699 and here's a less technical blog post discussing the issues http://resonaances.blogspot.co... . I'm sick of pop-sci websites peddling stuff that particle physicists have already moved on from as the "latest exciting discovery"
Both CMS and ATLAS are seeing bumps in certain Higgs channels around 125 GeV. While the bumps aren't big enough to be press-release worthy (2-3 sigma), a lot of particle physicists think that this is it. There will be an announcement on Dec 13th, and from now on it'll just be a matter of waiting till the bumps are 5 sigma and we can say for sure sure.
Ughh. Pseudo-scientific pop-physics mumbo jumbo. I suggest working through Griffiths or some other elementary QM book as a cure for pop-QM induced retardation.
A study, with so much bluster, and they studied just 94 people. Chuck a couple of zeros on that, then perhaps you have the makings of a worthwhile study and not just an anecdote.
Ugh. Not another math illiterate person complaining about the sample size. For the last time, your intuitive notions of statistics are worthless. The gamer study had a lot of people repeating this stupid objection too.
I am increasingly sick of these kinds of studies that use a sample pool so small as to be statistically irrelevant.
No, it's just that your intuitive ideas of what kind of sample size is statistically relevant are invalid. I am sick of how many people keep saying this even though it was addressed in an earlier post http://games.slashdot.org/comments.pl?sid=1341207&cid=29120539 .
Also, the complaints about the sample size being restricted to Seattle are probably unwarranted. The sample size is large enough to provide a 95% confidence level for a reasonably small interval, and it would be highly unusual for such a general result that's true in Seattle to be significantly different for other cities.
It would imply that there was some confounding variable that's exclusive to Seattle that modifies the characteristics of gamers, which is an absurd assumption, and the only reason you would think so without other evidence is if you just didn't like the results of the study.
extremely fragile it being at the limits of it's tenuous exitence after a long space journey.
This is completely unjustified. Might be true in a few special cases but no reason to assume it in general.
When people say evolution they don't just mean descent with modification, they mean the hypothesis that descent with modification (and other little things perhaps) is responsible for all the various species, and that this is how they descended from a common (and probably) single ancestor. It it this hypothesis that does not make (sufficiently) falsifiable predictions. Descent with variation is rather trivial and was known before and independent of Darwinian evolution. Anyone who breeds anything knows this.
The Maldacena duality can't be used to 'make predictions' with a string theory, its just a correspondence between a string theory and a conformal field theory. It's useful because sometimes calculations which are hard in a CFT can be made in the corresponding string theory which is sometimes easier (or vice versa). It cannot be used to support the physical validity of some string theory.
when your alternative is wage parity with taxi drivers, not such a bad choice. Rail on you rebel you.
Which taxi driver makes over 100K? He is a tenured professor. The point of tenure is that you can say what you think is right without being worried about your salary/livelihood.
Apparently the use of the term 'teleportation' is causing a lot of confusion. In QM, two particles that have identical states (quantum numbers) are considered indistinguishable; if they were switched, you wouldn't know. TFA describes a process that allows an entire state to be transferred instantaneously from one particle (or system) to another, and since in QM they are the same, the particle has been 'teleported'. There is nothing superluminal here, since before the state can be transferred you have to send some information across at kosher speeds.
They know it was entangled because they prepared the state way. For example, if you have a spin zero particle that splits up into two particles, and you measure one as spin up, the other must be necessarily spin down, no matter how far away it is, because of the conservation of angular momentum. Or you can think of a neutral particle splitting into positive and negative ones. So I guess it is ultimately the consequence of some conservation law.
What we have is that classical mechanics is a particular approximation of general relativity, at one end of the scale, and of quantum mechanics, at the other.
Not quite, they describe different things, so you can put them on the same scale. Classical mechanics is a framework for describing the dynamics of a system once you specify the forces. QM is a different framework. But GR is a theory for describing a particular force, gravity.
A wonderful example iirc is the spinning top. In classical mechanics, the top cannot be solved exactly. But in general relativity, the top can be solved exactly in about one page
This doesn't make any sense IMO, unless you can come up with something to back it up. If you mean the precession of a top in the presence of gravity, then sure it can be solved analytically in classical mechanics, but the general two body problem has no analytical solution in GR, and I doubt the restriction to a top simplifies it enough to allow a closed form solution. But I can give you valid examples that suggest the opposite. In classical mechanics, the dynamics under a linear potential (constant force) is very simple: constant acceleration in one direction. But try solving that in quantum mechanics, and what you get are hideous Airy functions to describe the position of the particle.
The designer, then, still has the last laugh, until there is a TOE, if there ever is.
Not even then. I don't know what it means among laypeople, but for a physicist TOE means a quantum field theory that describes gravity, electroweak and strong force. I can guarantee that we will have such a theory in 100 years, and probably a lot less. I can also guarantee that this TOE will eventually be superseded by a more accurate theory.
it is interesting to note that the universe is mainly built out of second order laws. This means that in many cases there are a small number of poles or zeros that can control macroscopic behaviour and often analytic solutions exist. This would be how a designer would do it.
Nope. It is just that scientists use simple models like harmonic oscillator for most systems, simply because they are easy to solve. That doesn't mean that the universe is 'built' from second order laws. The rest of your post is also similar misinterpretations of QM, optics etc
But will it run Crysis?
IMHO everyone seems to have missed the most glaring flaw in the study. 140 countries that 'practice polygamy'? Really? I strongly doubt that there are 140 countries where the number of polygamists is statistically significant and is large enough to cause a measurable effect on a property of the average male. And only 49 'mostly monogamous' countries? Rubbish.
The problem seems to be the 'monogamy scale' mentioned in the article. Perhaps they considered every country where polygamy in some form is legal as ones that 'practice polygamy'. For example in India, polygamy is legal (only) for Muslims, but there are so few Muslims that practice it that it cannot possibly have any effect on the average male. So this correlation observed among countries that 'practice polygamy' (which in reality just have a tiny causally insignificant number of polygamists) is probably just noise.
M-x neo-matrix-vision is better. Thus Emacs > *
once the water was turned into oxygen and helium
If they can turn hydrogen->helium with just sunlight and 1.2V, we will soon be turning base metals into gold...
Not all the axioms are set in stone. It's possible that special relativity could be violated. That's pretty outlandish, but maybe even a small violation would break the theorem. So if some future theory is only approximately Lorentz covariant this theorem may not apply. http://en.wikipedia.org/wiki/Lorentz_invariance#Lorentz_violation Also, entanglement only lasts for one wave collapse, but it seems their thought experiment involves multiple collapses. I haven't finished reading the paper yet so I'm not sure if this affects the conclusion.
I don't care much for fluid mechanics, I was just miffed that we only did Lagrangian/Hamiltonian dynamics for systems of discrete particles (and that is all there is in M&T). That semester I was starting some independent study on QFT (well I was just looking at rel. QM and classical field theory at that point) so it really would've helped if we had generalized to fields instead of just discrete/finite particles. We spent a lot more time on boring Newtonian crap instead (who wants to study stupid Newtonian gravity, even if it is in-depth, their junior year?), which I blame on the content of the book. The rest of the class actually did very poorly in the course; but that is what happens when you ask too little of students. It was so boring I missed 90% of the lectures.
Thus: an M&T based class mech course certainly does not cater to an advanced undergraduate.
Haha. Marion and Thornton is an *excellent* advanced-undergraduate text for classical mechanics. For that level of student, you really can't go wrong with it.
Bullcrap. My undergrad mechanics course was based on Marion and Thornton, and I was disappointed with how little we learned of variational methods and hamiltonian dynamics. And of course, there is no field mechanics AT ALL. Advanced undergraduate my ass.
Marion and Thornton sucks monkey balls. Stay away.
I only meant that he will be ready for Hartle if he has a general idea of field mechanics, and he doesn't have to put off reading it until he is thoroughly done with Goldstein, which will take quite a while.
Do NOT use the Feynman lectures as a starting point. They are fun to read and will give you a lot of insight if you already know what he is talking about, but I don't know anyone who learned intro physics for the first time from them. I tried it myself in the 11th/12th grade, and didn't get very far. I would suggest you try books that are somewhere between upper level undergrad and beginning grad level. The main obstacle undergrads face while reading this books is not having the requisite math background; but this should not be a problem for you. So for class mech, use Goldstein. For QM, Sakurai's Modern QM. For EM, use Griffiths, I don't think you should jump into Jackson just yet. For thermo, Schroeder. Supplement all of these with Boas' Mathematical Methods, if there is any math you need to review or learn. After you've skimmed through Goldstein, you might also wanna try Hartle's Gravity, this will probably be the most useful for astrophysics.