But no, your idea doesn't work whether A and B see the same result or different results Victor can still decide to entangle their photons or not.
If A and B have the same result and Victor decides to entangle their results then he can say "Hey, you got the same result as each other" even though they haven't told him they did. If they got different results then Victor can say "Hey, you got different results"
OK. I've now read the paper as far as page 4 and you're right. There's no violation of causality at all.
Not only do A and B need to compare results, they also need to know what Victor measured and what his result was in order to see the entanglement (or not) between their measurements.
To try and summarize,
A and B have made a measurement that has one of two results H or V for each of them giving a set of results HH, HV, VH and VV
Victor makes one of two measurements that each have four possible results, HH, HV, VH and VV
If Victor makes measurement 1 and gets HV or VH then he can deduce that A and B got the same result but he cannot tell which of the two possible results they got, just that they will have been the same. i.e. half the time A and B will have got result HH and half the time they will have got VV
If Victor makes measurement 1 and gets HH or VV then he can deduce that A and B got opposite results but cannot tell who got which result. i.e. half the time A and B will have got HV and half the time they will have got VH
(I think I've got these the right way around but I'm not 100% sure, it could be that Victor getting HH or VV implies that AB is also one of HH or VV)
Measurement 1 causes A and B's photons to become entangled but separable from Victor's pair.
If Victor makes measurement 2 then he can deduce exactly what results both A and B got but the results they got will be completely random. i.e. in 1/4 of the time he gets HH and they get VV, 1/4 he gets HV and they get VH etc. This is the standard entanglement test where the result of A (or B) predicts what Victor will see.
Just wait till IPv6 becomes standard and users will have to take an active role in personal firewalls....
I don't see why you would think this would be the case.
Pretty much every current IPv4 router[1] comes by default in a NAT configuration. To enable bridging, port forwarding etc generally requires changing settings on the router.
There's absolutely no reason why IPv6 routers can't have a stateful firewall that blocks incoming connections by default. It's LESS difficult to do than NAT as there doesn't need to be packet inspection etc for things like FTP.
[1] My cable modem operates in a bridged mode. I'm pretty sure I didn't change that but I could be wrong. It was a while ago now that I set it all up.
and in my opinion you're more likely to have a happy, productive life if you don't have them.
The new iPad has finally provided something I've been asking for for the last 5+ years. And that is a screen with a high enough resolution that A4 pages can be displayed well enough that they can be read without issue.
I have two things I want to be able to carry around with me and read. 1. Scientific papers. While you can print them out they are bulky and heavy, especially if you want five or six on hand at once. 2. Sheet music. I play the piano but I do not have the sort of memory where I can play through something a few times and then it's committed to memory. Even the stuff I have committed to memory I lose again if I don't play through it nearly every day.
For neither use is the iPad perfect. Scribbling notes in the margin of a paper is easier when it's printed out than when it's on the iPad and trying to write in fingerings on music is hopeless on the iPad. Finally, turning the page while playing the piano is surprisingly difficult on the iPad. I had assumed it would be easier than using sheet music but so far it's not. Maybe with practice. A little foot switch that plugs in would be perfect.
I would swap my iPad for a eink reader with a similar resolution. But I hope, at last, the iPad is the start of screens that actually have a decent dpi. This race to bigger and bigger screens with no more pixels has been driving me crazy and, when I talk to people, this isn't an uncommon complaint.
Your confusion, misunderstanding and naive, incorrect guess as to what happens when you increase the concentration of CO2, was conclusively resolved experimentally in the late 1940s and early 1950s with the advent of high altitude aircraft.
There are plenty of sites that go into this in various levels of detail. Any site that puts forward an argument like yours is wrong. realclimate is a good starting point for finding reputable sources.
We could be at a point that even if demand fell off, the traders who last purchased the oil have enough cash that they dont have to actually sell it, they can just wait until demand picks bak up, and always sell high.
It doesn't work like that. Once the future matures you are obliged to deliver or take delivery. Having lots of cash lets you avoid getting wiped out by margin calls due to a temporary dip in the future's price.
A few years ago (3rd October 2006) there were a few trades where the spot price of gas in the UK went negative. Speculators had agreed to take delivery of gas and had left it as long as they possibly could to close out their position. Eventually they were forced to find a buyer for the gas they had agreed to buy.
Re Mythical Man-Month: "If you throw more people onto a project from day one of a year+ long project, you sure can expect more productivity."
Having just reread this book this isn't what it says at all.
What it actually says is that there is a minimum elapsed time for doing a project based on an optimum staffing. Increasing OR decreasing the number of people from that optimum will result in the project taking longer.
What he is saying is that when you write code it should do what you expect it to do.
You should never, EVER, be using the debugger to find out what your code is doing. You might sometimes use the debugger to find out why it isn't doing what you expect.
This is completely orthogonal to not knowing what your code/should/ do. Prototyping, iterating, throwing one away can all help with improving the requirements gathering.
People who use debuggers to find out what their code is doing, fix the symptoms of whatever bug they are investigating and leave the bug festering. Later, someone more competent spots the bug in their code and tries to fix it only to discover there is layer upon layer of hack working around the problems it is causing and it's almost impossible to do anything at all with the code.
Eventually, the only way forward remaining is to rewrite the code from scratch. But if you're going to rewrite a chunk of code, the first requirement is to understand what it is doing. When you have code that even the original programmer didn't understand when they originally wrote it the only real solution is to put one of your very best programmers to understanding the requirements, finding the unstated assumptions that are baked into this incomprehensible mess and sorting out the issues.
I call these incompetent programmers "coincidence programmers." They keep making random changes until their code appears to work for the one test case they actually have. If it were such a great way of programming, or even if it were marginally useful then we wouldn't need programmers at all. Computers can do what these people do far better than people can.
Don't think you can count any of those authors as forgotten.
None of these are forgotten but I'm often surprised that people haven't read them.
The Midwich cuckoos and The Chrysalids are my two favourites by John Wyndham. Everyone has heard of "The Triffids" but some of his other works are better but less well known.
The Death of Grass by John Christopher.
The Tripod trilogy, also by JC for teenagers.
Anything by Stanley Weinbaum.
And, not forgotten but always underrated, Animal Farm by George Orwell. As a child, it's a great (sad) fantasy about talking animals. As a teenager it's an interesting work but outclassed by 1984. And as an adult it's a chilling documentary about corruption by power.
It always makes me despair when I see 1984 being rated above Animal Farm. Have all the people voting not read these stories again since being forced to at school?
While it is true that NAT itself isn't a security feature, being limited to only a single IPv4 address and being forced to hide all devices behind a single IP address actually is. With a typical single-IPv4 address NAT network you simply can't expose all your devices to the Internet, it's impossible.
Actually, a huge number of users CAN expose all their machines to the internet even when using NAT because for many people they only have one machine.
Most, if not all, home routers are default configured not to forward much or anything but there's absolutely no reason why an IPV6 home router can't also block everything by default.
What IPV6 will mean is that hackers won't just be able to scan the entire IPV6 address space looking for vulnerable machines.
Which was patented (at least according to wikipedia). But maybe Kodak licenced the patent very cheaply or competitors just didn't use it until the patent had expired.
Indeed. You deprived someone of their property. Now let's get back on topic and start talking about copyright infringement.
For a car analogy, it's perhaps better to think of copyright infringement as copying someone's numberplates.
This is (apparently - I don't know anyone who has suffered this problem although I've seen reports in the news) a sufficiently frequent occurrence in the UK that nowadays you cannot (legally) buy numberplates without providing documentation to show that you are the "owner" of the number.
I'm sure numberplate theft does occur but usually, people only discover their numberplates have been cloned when they get a speeding ticket or parking fine in the post.
"Caffeine is highly addictive, and you cannot simply quit without severe side effects if you drink coffee daily."
People are obviously different. I drink a fair amount of coffee on a daily basis. But when I've gone cold turkey I've had absolutely no symptoms at all.
Drinking coffee for me becomes a habit, not an addiction. And it's a relatively easy habit to break because you have time between getting up to get another coffee and actually getting it to realize what you are doing. The first time I realized I should probably try to moderate my coffee intake a bit was when I realized I was boiling the kettle for the next mug of coffee before I'd finished drinking the previous one. So I stopped drinking coffee completely there and then and didn't have another coffee (or tea or any other caffeinated drink) for a couple of months and I had no symptoms at all other than sometimes catching myself walking to the kitchen to put the kettle on.
I used to bite my nails. That was an extremely hard habit to break. Not because I was addicted to biting them but because I wasn't even aware that I was chewing them. I still often chew the skin from around my nails (to the point where I can draw blood) and that is proving just as hard to stop.
I've looked at your post 8 times so far, and it always returns 7 and 3 as random numbers. It's not so random when it always returns the same predictable values.
What a wonderful life it must be to see everything in a consistent base. If it weren't for slashdot's threading I wouldn't have been able to tell what post you were replying to.
and ask them "is this obvious?" and they will almost always say yes, though when you ask "why hasn't it been done before?" the answer comes back a little more murky
That's because you're asking the wrong question.
What you should be doing is a) asking yourself what problem the patent is trying to solve. b) going to an "expert in the field" and giving them the problem to solve and asking them to come up with a solution to the problem.
If b) turns out to be difficult then the patent is a good patent. But most patents haven't been implemented before because nobody has asked for it before.
It would be like patenting "gold plating a car" and then, years later, claiming royalties on cars because they were using gold plated connectors.
If we had any sense at all, we would shut down every nuclear power plant until we had evidence that we had developed human beings who are smart enough to run them properly without ever screwing up.
And, by the same logic we'd shut down every fossil fueled power plant until we knew it was safe to operate them while dumping their emissions willy nilly into the atmosphere.
This experiment isn't "racing" neutrinos against photons. It's measuring the distance between two points and then timing the neutrino over that distance and finding that it appears to be faster than the defined value of c.
I cannot see why photons travelling at a speed other than c would have any bearing on this experiment. IMO photons (any massless particle) not travelling at c is even more objectionable than exceptionally high energy neutrinos travelling measurably faster than c. YMMV
The most likely explanation for the CERN results (apart from experimental error) is that neutrinos are tachyonic -- they have imaginary mass, and naturally fly faster than light. The higher their energy, the closer to lightspeed they travel.
This would be backwards. SN1987A neutrinos were in the 10MeV range so should be much more super-luminal than the 17GeV neutrinos being measured at CERN. So I think that rules out tachyonic neutrinos.
Assuming that this is a real result, the most likely explanation is going to be the emergence of new physics when KE is very much (10^10 times) greater than rest mass.
Some sort of frame dragging a la alcubierre drive would be one possibility that possibly doesn't have to throw out relativity.
Surely with an undergraduate degree you did the derivation of the wave equation in free space from Maxwell's equations?
The only part you might have missed (I'm sure you'll have been told it but might not have realized the significance) is that Maxwell's equations are independent of the inertial frame that you pick. And therefore light propagates at c in all inertial frames.
Special relativity is what falls out if you assume that Maxwell's equations are correct.
There's all sorts of experiments that have been done that make any of this really hard to throw out. From EM having inverse square law to half-lives of relativistic particles.
The only handle that makes me think there's a slim chance there might be something real here is that we are WAY outside the normally experienced velocities for massive particles. We're talking about a 2eV rest mass with a KE in the 17GeV range. Therefore we could be seeing new physics while still having relativity as a very good approximation for everything we've had so far much like relativity was a small correction to newtonian mechanics.
Slashdot Mirror
I've written a longer response here:
http://science.slashdot.org/comments.pl?sid=2808465&cid=39793139
But no, your idea doesn't work whether A and B see the same result or different results Victor can still decide to entangle their photons or not.
If A and B have the same result and Victor decides to entangle their results then he can say "Hey, you got the same result as each other" even though they haven't told him they did. If they got different results then Victor can say "Hey, you got different results"
Tim.
OK. I've now read the paper as far as page 4 and you're right. There's no violation of causality at all.
Not only do A and B need to compare results, they also need to know what Victor measured and what his result was in order to see the entanglement (or not) between their measurements.
To try and summarize,
A and B have made a measurement that has one of two results H or V for each of them giving a set of results HH, HV, VH and VV
Victor makes one of two measurements that each have four possible results, HH, HV, VH and VV
If Victor makes measurement 1 and gets HV or VH then he can deduce that A and B got the same result but he cannot tell which of the two possible results they got, just that they will have been the same. i.e. half the time A and B will have got result HH and half the time they will have got VV
If Victor makes measurement 1 and gets HH or VV then he can deduce that A and B got opposite results but cannot tell who got which result. i.e. half the time A and B will have got HV and half the time they will have got VH
(I think I've got these the right way around but I'm not 100% sure, it could be that Victor getting HH or VV implies that AB is also one of HH or VV)
Measurement 1 causes A and B's photons to become entangled but separable from Victor's pair.
If Victor makes measurement 2 then he can deduce exactly what results both A and B got but the results they got will be completely random. i.e. in 1/4 of the time he gets HH and they get VV, 1/4 he gets HV and they get VH etc. This is the standard entanglement test where the result of A (or B) predicts what Victor will see.
Tim.
I don't see why you would think this would be the case.
Pretty much every current IPv4 router[1] comes by default in a NAT configuration. To enable bridging, port forwarding etc generally requires changing settings on the router.
There's absolutely no reason why IPv6 routers can't have a stateful firewall that blocks incoming connections by default. It's LESS difficult to do than NAT as there doesn't need to be packet inspection etc for things like FTP.
[1] My cable modem operates in a bridged mode. I'm pretty sure I didn't change that but I could be wrong. It was a while ago now that I set it all up.
Tim.
The new iPad has finally provided something I've been asking for for the last 5+ years. And that is a screen with a high enough resolution that A4 pages can be displayed well enough that they can be read without issue.
I have two things I want to be able to carry around with me and read.
1. Scientific papers. While you can print them out they are bulky and heavy, especially if you want five or six on hand at once.
2. Sheet music. I play the piano but I do not have the sort of memory where I can play through something a few times and then it's committed to memory. Even the stuff I have committed to memory I lose again if I don't play through it nearly every day.
For neither use is the iPad perfect. Scribbling notes in the margin of a paper is easier when it's printed out than when it's on the iPad and trying to write in fingerings on music is hopeless on the iPad. Finally, turning the page while playing the piano is surprisingly difficult on the iPad. I had assumed it would be easier than using sheet music but so far it's not. Maybe with practice. A little foot switch that plugs in would be perfect.
I would swap my iPad for a eink reader with a similar resolution. But I hope, at last, the iPad is the start of screens that actually have a decent dpi. This race to bigger and bigger screens with no more pixels has been driving me crazy and, when I talk to people, this isn't an uncommon complaint.
Tim.
Two words: Lapse rate.
Your confusion, misunderstanding and naive, incorrect guess as to what happens when you increase the concentration of CO2, was conclusively resolved experimentally in the late 1940s and early 1950s with the advent of high altitude aircraft.
There are plenty of sites that go into this in various levels of detail. Any site that puts forward an argument like yours is wrong. realclimate is a good starting point for finding reputable sources.
Tim.
It doesn't work like that. Once the future matures you are obliged to deliver or take delivery. Having lots of cash lets you avoid getting wiped out by margin calls due to a temporary dip in the future's price.
A few years ago (3rd October 2006) there were a few trades where the spot price of gas in the UK went negative. Speculators had agreed to take delivery of gas and had left it as long as they possibly could to close out their position. Eventually they were forced to find a buyer for the gas they had agreed to buy.
Tim.
Re Mythical Man-Month: "If you throw more people onto a project from day one of a year+ long project, you sure can expect more productivity."
Having just reread this book this isn't what it says at all.
What it actually says is that there is a minimum elapsed time for doing a project based on an optimum staffing. Increasing OR decreasing the number of people from that optimum will result in the project taking longer.
Tim.
Cherenkov radiation is only given off by charged particles. But a quick google gives http://en.wikipedia.org/wiki/Askaryan_effect which is what I think you're referring to.
Tim.
No. No. No!
What he is saying is that when you write code it should do what you expect it to do.
You should never, EVER, be using the debugger to find out what your code is doing. You might sometimes use the debugger to find out why it isn't doing what you expect.
This is completely orthogonal to not knowing what your code /should/ do. Prototyping, iterating, throwing one away can all help with improving the requirements gathering.
People who use debuggers to find out what their code is doing, fix the symptoms of whatever bug they are investigating and leave the bug festering. Later, someone more competent spots the bug in their code and tries to fix it only to discover there is layer upon layer of hack working around the problems it is causing and it's almost impossible to do anything at all with the code.
Eventually, the only way forward remaining is to rewrite the code from scratch. But if you're going to rewrite a chunk of code, the first requirement is to understand what it is doing. When you have code that even the original programmer didn't understand when they originally wrote it the only real solution is to put one of your very best programmers to understanding the requirements, finding the unstated assumptions that are baked into this incomprehensible mess and sorting out the issues.
I call these incompetent programmers "coincidence programmers." They keep making random changes until their code appears to work for the one test case they actually have. If it were such a great way of programming, or even if it were marginally useful then we wouldn't need programmers at all. Computers can do what these people do far better than people can.
Tim.
Don't think you can count any of those authors as forgotten.
None of these are forgotten but I'm often surprised that people haven't read them.
The Midwich cuckoos and The Chrysalids are my two favourites by John Wyndham. Everyone has heard of "The Triffids" but some of his other works are better but less well known.
The Death of Grass by John Christopher.
The Tripod trilogy, also by JC for teenagers.
Anything by Stanley Weinbaum.
And, not forgotten but always underrated, Animal Farm by George Orwell. As a child, it's a great (sad) fantasy about talking animals. As a teenager it's an interesting work but outclassed by 1984. And as an adult it's a chilling documentary about corruption by power.
It always makes me despair when I see 1984 being rated above Animal Farm. Have all the people voting not read these stories again since being forced to at school?
Tim.
Actually, a huge number of users CAN expose all their machines to the internet even when using NAT because for many people they only have one machine.
Most, if not all, home routers are default configured not to forward much or anything but there's absolutely no reason why an IPV6 home router can't also block everything by default.
What IPV6 will mean is that hackers won't just be able to scan the entire IPV6 address space looking for vulnerable machines.
Tim.
I suspect it's confusion with the Bayer filter.
Which was patented (at least according to wikipedia). But maybe Kodak licenced the patent very cheaply or competitors just didn't use it until the patent had expired.
Tim.
For a car analogy, it's perhaps better to think of copyright infringement as copying someone's numberplates.
This is (apparently - I don't know anyone who has suffered this problem although I've seen reports in the news) a sufficiently frequent occurrence in the UK that nowadays you cannot (legally) buy numberplates without providing documentation to show that you are the "owner" of the number.
I'm sure numberplate theft does occur but usually, people only discover their numberplates have been cloned when they get a speeding ticket or parking fine in the post.
Tim.
"Caffeine is highly addictive, and you cannot simply quit without severe side effects if you drink coffee daily."
People are obviously different. I drink a fair amount of coffee on a daily basis. But when I've gone cold turkey I've had absolutely no symptoms at all.
Drinking coffee for me becomes a habit, not an addiction. And it's a relatively easy habit to break because you have time between getting up to get another coffee and actually getting it to realize what you are doing. The first time I realized I should probably try to moderate my coffee intake a bit was when I realized I was boiling the kettle for the next mug of coffee before I'd finished drinking the previous one. So I stopped drinking coffee completely there and then and didn't have another coffee (or tea or any other caffeinated drink) for a couple of months and I had no symptoms at all other than sometimes catching myself walking to the kitchen to put the kettle on.
I used to bite my nails. That was an extremely hard habit to break. Not because I was addicted to biting them but because I wasn't even aware that I was chewing them. I still often chew the skin from around my nails (to the point where I can draw blood) and that is proving just as hard to stop.
Tim.
The answer is to only use antibiotics when they're really useful and necessary.
http://www.spokesman.com/stories/2010/jan/03/norways-mrsa-solution/
Tim.
It's of the order of a centimetre at 50Hz in aluminium.
I've looked at your post 8 times so far, and it always returns 7 and 3 as random numbers. It's not so random when it always returns the same predictable values.
What a wonderful life it must be to see everything in a consistent base. If it weren't for slashdot's threading I wouldn't have been able to tell what post you were replying to.
Tim
I hadn't noticed the shortened word count. I also didn't find it funny.
Timing is everything and maybe those missing 20 words while not being necessary to the "joke" are essential to the timing.
This cartoon is my favourite joke:
http://svalko.org/data/2011_11_05_17_55_964161_1.jpeg
Tim.
No. Bell's inequality says that there can be no local hidden variable theory compatible with special relativity.
Tim.
and ask them "is this obvious?" and they will almost always say yes, though when you ask "why hasn't it been done before?" the answer comes back a little more murky
That's because you're asking the wrong question.
What you should be doing is
a) asking yourself what problem the patent is trying to solve.
b) going to an "expert in the field" and giving them the problem to solve and asking them to come up with a solution to the problem.
If b) turns out to be difficult then the patent is a good patent. But most patents haven't been implemented before because nobody has asked for it before.
It would be like patenting "gold plating a car" and then, years later, claiming royalties on cars because they were using gold plated connectors.
Tim.
If we had any sense at all, we would shut down every nuclear power plant until we had evidence that we had developed human beings who are smart enough to run them properly without ever screwing up.
And, by the same logic we'd shut down every fossil fueled power plant until we knew it was safe to operate them while dumping their emissions willy nilly into the atmosphere.
Tim.
In England the spirit measure was 1/6 gill which was smaller than the new 25ml but in Scotland it was 1/5 gill which was larger.
Tim.
This experiment isn't "racing" neutrinos against photons. It's measuring the distance between two points and then timing the neutrino over that distance and finding that it appears to be faster than the defined value of c.
I cannot see why photons travelling at a speed other than c would have any bearing on this experiment. IMO photons (any massless particle) not travelling at c is even more objectionable than exceptionally high energy neutrinos travelling measurably faster than c. YMMV
Tim.
The most likely explanation for the CERN results (apart from experimental error) is that neutrinos are tachyonic -- they have imaginary mass, and naturally fly faster than light. The higher their energy, the closer to lightspeed they travel.
This would be backwards. SN1987A neutrinos were in the 10MeV range so should be much more super-luminal than the 17GeV neutrinos being measured at CERN. So I think that rules out tachyonic neutrinos.
Assuming that this is a real result, the most likely explanation is going to be the emergence of new physics when KE is very much (10^10 times) greater than rest mass.
Some sort of frame dragging a la alcubierre drive would be one possibility that possibly doesn't have to throw out relativity.
Tim.
Surely with an undergraduate degree you did the derivation of the wave equation in free space from Maxwell's equations?
The only part you might have missed (I'm sure you'll have been told it but might not have realized the significance) is that Maxwell's equations are independent of the inertial frame that you pick. And therefore light propagates at c in all inertial frames.
Special relativity is what falls out if you assume that Maxwell's equations are correct.
There's all sorts of experiments that have been done that make any of this really hard to throw out. From EM having inverse square law to half-lives of relativistic particles.
The only handle that makes me think there's a slim chance there might be something real here is that we are WAY outside the normally experienced velocities for massive particles. We're talking about a 2eV rest mass with a KE in the 17GeV range. Therefore we could be seeing new physics while still having relativity as a very good approximation for everything we've had so far much like relativity was a small correction to newtonian mechanics.
Tim.