THE FOLLOWING CONTEST IS INTENDED FOR PLAY IN THE UNITED STATES AND SHALL ONLY BE CONSTRUED AND EVALUATED ACCORDING TO UNITED STATES LAW. DO NOT ENTER THIS CONTEST IF YOU ARE NOT LOCATED IN THE UNITED STATES.
Even though there is a country field in the form. WTF?
They don't mention that on the form page, either. It peeves me just a little bit that they would do that, I mean, how many people actually read these conditions things, anyway? Can't say I'm surprised, though.
Absolutely correct. The way it's written in the text is a bit misleading. A qubit can be 0, 1, or some proportion of 0 and 1. It's like a continuum between 0 and 1, and a qubit can take any place along that continuum.
The tricky thing is, quantum mechanics won't let you measure anything other one of two values (not strictly true, but go with me on this). But those values don't necessarily have to be 0 and 1, just so long as they are orthogonal to each other.
Okay, to understand that last bit you need to bring in the fact that the proportions of 0 and 1, x and y say, can actually be any complex number, positive, negative, imaginary, whatever, just so long as their magnitudes-squared add to 1. So, then, instead of measuring for the 0 and 1 states, you could measure for "0.5" and "-0.5" states.
This isn't even getting to the confusion of putting these things into gates.
Isn't Conroy the guy pushing for ISP-level internet filtering of porn/violence/sedition/etc. (for the good of the-children, of course)? With a waste-of-resources policy that unfeasible, how's that bode for the knowledge of him and of his advisers?
What if every feature I could want on a cellphone isn't softmoddable? I might want more RAM, or a faster CPU, or an advanced GPU. I might want a bigger screen or a different form factor. I might even want it to make me eggs.
I built and program my computer. To my computer I am God. I expect my computer to behave as I expect it to behave or I'll take the damned thing apart and fix it.
Then why won't God just fix me, instead of threatening me (which as far as I know isn't a bluff) with eternal hell-fire?
In fact, your analogy is worse than that. The reason your computer misbehaves is because 1) impure materials, 2) poor or incomplete design, and/or 3) poor or incomplete construction due to your own problem or failure. You'll note that all three are in a big way outside of your control, so you get some cop-out. But, supposedly, none are outside of God's control.
So why does this God, after failing to make me and this world correctly WHICH HE WAS QUITE CAPABLE OF DOING, and thus is HIS OWN DAMN FAULT FOR NOT DOING SO, turn around and BLAME ME and PUNISH ME for what was ultimately HIS MISTAKE? It's disturbingly childish.
You might trot out the "free-will" silliness, but all that does is imply that there is some sort of universal law GREATER THAN God - the law of free will. If not, then ultimately we're back at it all being God's doing, and thus God's fault.
What kind of hubris must you have to think you're God's equal?
You're right, I'm not equal to God. I'm better than him: I'm less childish, less violent, less misogynistic, and know more about the physical world than he. And I posit that many people on this planet, yourself included, are better than that God, too.
But what if a potential employer (or HR staff, whatever) had done such a search, and found one of your namesake's recipe for crystal meth? You had better hope that employer is smart enough to realise it isn't the same person, but do you honestly believe that?
I've heard stories (on./ mind you) about companies doing google searches and the like on potential employees, and I can see how an applicant would consider the use of these services, perhaps for some specific reason, or just to clean their google-reputation generally, to get an edge over their competition. What worries me, though, is that employers actually take such searches seriously. The phrase "The internet is serious business" is meant to be a joke, but it seems to go over some people's heads.
I wonder if in the future we'll ever see legislation against discrimination by internet search? Not for a while at least, I posit --- there are probably more deserving unlegislated discriminations to target first.
No, there has to be some sort of classical communication between the two points for the teleportation to work. If the two points are completely isolated from each other, then the last step, a special measurement on B chosen based on the result of the first measurement on A, doesn't make sense.
The neat thing about teleportation is that the state of particle A gets sent over to B (being rough with my description, technically, but it'll do) *without knowing what that state actually is*. The measurement done on A that needs to be sent to B doesn't actually give a complete description of the state, and that's why it will be useful for encryption. But without the result of that measurement the state can't be faithfully teleported to B. There really does have to be an old-fashioned communication channel between the two parties for it to work.
Sorry, it's not possible to read the teleported state change. The reason is that as soon as you measure particle A without regard to the result of a measurement of particle B the entanglement is practically lost.
You need the joint measurements of A and B in combination (either the result of A determines how B is measured, or vice versa). If you didn't know the result of the first, then you can't be sure how you're supposed to measure the second, and you could well pick the wrong measurement. Then the result will be completely random.
The reason we know it's not bollocks is because after all the measurements there are clear correspondences between the results. If there was no teleportation, these correspondences would be different. If there was no entanglement, there wouldn't be these correspondences at all.
Thus it won't extend to multiple photons like you describe. There are other tricky teleportation schemes using multiple photons, though, like superdense coding which I mentioned in another comment.
Not that it's not understood, or that the maths doesn't make sense, or that nature doesn't fit its predictions, but quantum mechanics is weird, counter-intuitive stuff. Niels Bohr, one of the pioneers of QM: "If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet."
For your first question: I'm not so sure about the fundamental limits there, but the practical limits are improving all the time.
For your second question: yes. It's called Superdense coding. Wikipedia puts it succinctly: Superdense coding is a technique used in quantum information theory to send two bits of classical information using only one qubit, with the aid of entanglement.
Wrong. Completely and utterly wrong. You can't send information faster than the speed of light.
Quantum teleportation doesn't work like that. Here's basically how it works: Two quantum particles are entangled. Then they are separated from each other, one goes to point A the other to B. If you do a measurement on A and COMMUNICATE THE RESULT OF THAT MEASUREMENT to where B is. The other guy can do a special measurement on B based on what A's result was. Then the state of A becomes what the state of B was originally. The particles have not moved (the measurements have changed their states, though), but A's state has been "teleported" to B. It's all to do with the fact that the two particles were entangled in the first place.
But the very important point is that you *still have communicate the result of the first measurement*, which means you're limited to the speed of light.
There is still application for encryption since just knowing what the result of the measurement was is not enough without having the actual entangled particle B.
BUT THERE IS NO APPLICATION TO STAR TREK-LIKE TELEPORTATION OR FASTER THAN LIGHT-SPEED COMMUNICATION. And frankly I'm getting tired of seeing the same wrong information getting played in the media like this. And slashdot even, come on guys, you should know better by now. I'm new here, aren't I?
Knowledge of TeX/LaTeX is pretty much a prerequisite in the Maths and Physical Sciences. I'm not so surprised that a CS major missed out. No disrespect, one of my majors was CS, too.
It depends on what you typically write, but once you learn LaTeX you might find it hugley more sensible than any WYSIWYG system. I did.
A thousand times yes. Using TeX is standard practice for physics and math papers. Why is it that Nature (not sure about Science) does not accept TeX documents? DOC? Why?
It's probably the fault of the biologists. Silly biologists.
But besides, Nature (again, not sure about Science) takes DOC files that have to be formatted in a certain way that is quite different to what ends up in the journal. They accept PDF like that, too, which is interesting.
So, these guys are saying that the act of making an educated guess (which they call "free will"), rather than a concrete logical decision or a complete stab in the dark, is not limited to humans? Nice to know, but I don't find it at all surprising. I mean, if any creature did anything other than make educated guesses they'd be extinct pretty quick. Either because they randomly chose the really stupid option or they took to long to decide.
Oh? I didn't realise. But surely that doesn't mean that a completely quantised representation of the universe would be sufficient. In quantum mechanics continuously variable amplitudes are used to describe superposition states. I don't see how those can be quantised sufficiently without breaking important quantum mechanics like entanglement. Sure, you can't measure an amplitudee without collapsing to some state, but they can be inferred by measurements over populations of identically prepared states.
Or do the Planck units ultimately limit the accuracy of quantum amplitudes, too?
I have a vague feeling this also relates to the Bell inequality, somehow. But now I'm just wondering out loud.
I guess the point I was trying to make here is that just because you can't measure something doesn't necessarily make it equivalent to being quantised. But then, I'm not totally convinced how true that is.
[quote]There are no such thing as analog values in this universe, everything is quantized.[/quote]
Absolutely not true. Position is not a quantised value, nor is any of its time derivatives (velocity, acceleration, impulse) and related values (momentum, force, kinetic and potential energy. Time is not quantised. Phase is not quantised, nor wavelength. There's a whole field of physics interested in continuous-variable quantum mechanics.
That was a bit silly to say, actually. Perhaps you meant to say that all particles are quantised, but that's a tautology.
I honestly don't like most Simpsons episodes post 2003 at the latest. I was reading the parent and thinking to myself, "Yeah, that might be why."
But then I read the bit about Family Guy. I like Family Guy. So if you're equating the newer Simpsons episodes to Family Guy, I'm not sure what the reason for my distaste is.
Perhaps it's just a general decrease in the wittiness of the Simpsons that has lost me. I recall old episodes seemed much wittier than the new ones. Family Guy has wit too, perhaps less than old Simpsons, but it also has some shock humour that, at least for me, seems make up for that.
I don't know. Perhaps I just got older.
- These lunchbreak pseudophilosophical ramblings brought to you by particles. For that rich quantum-mechanics flavour, choose particles.
kW/h would have to be a measure of the rate of change of a power source. Perhaps as a measure of fluctuation, or something. Not sure how common it is (probably not very) or if another unit of measure is more common, if it is used by anyone at all.
If I could just have a moment of your time, are you aware of all the dangers faced by children in society these days? Simple things like colds and scrapes and growing pains, to the frightening reality of paedophiles, child molesters, apathetic parents and abandonment, gangs and violent computer games and widespread pornography on the internet. Don't you think something needs to be done about it all?
I'm asking people to sign this petition I have here. I'm looking for signatures to convince the government to do something about all these problems once and for all. The solution is actually surprisingly simple, but our elected officials don't seem to have realised it, yet. All we have to do is ban children.
Yes, ban children. It's guaranteed to work! Wait, don't go! It'll really work! All you have to do is get rid of all these bloody kids and then you won't have to think of the children ever again, because there won't be any more children to think of! Isn't that wonderful?!
Slashdot Mirror
Second paragraph of the rules:
THE FOLLOWING CONTEST IS INTENDED FOR PLAY IN THE UNITED STATES AND SHALL ONLY BE CONSTRUED AND EVALUATED ACCORDING TO UNITED STATES LAW. DO NOT ENTER THIS CONTEST IF YOU ARE NOT LOCATED IN THE UNITED STATES.
Even though there is a country field in the form. WTF?
They don't mention that on the form page, either. It peeves me just a little bit that they would do that, I mean, how many people actually read these conditions things, anyway? Can't say I'm surprised, though.
Absolutely correct. The way it's written in the text is a bit misleading. A qubit can be 0, 1, or some proportion of 0 and 1. It's like a continuum between 0 and 1, and a qubit can take any place along that continuum.
The tricky thing is, quantum mechanics won't let you measure anything other one of two values (not strictly true, but go with me on this). But those values don't necessarily have to be 0 and 1, just so long as they are orthogonal to each other.
Okay, to understand that last bit you need to bring in the fact that the proportions of 0 and 1, x and y say, can actually be any complex number, positive, negative, imaginary, whatever, just so long as their magnitudes-squared add to 1. So, then, instead of measuring for the 0 and 1 states, you could measure for "0.5" and "-0.5" states.
This isn't even getting to the confusion of putting these things into gates.
And it's been 100% since they were introduced.
Isn't Conroy the guy pushing for ISP-level internet filtering of porn/violence/sedition/etc. (for the good of the-children, of course)? With a waste-of-resources policy that unfeasible, how's that bode for the knowledge of him and of his advisers?
Ours (AU) is basically "faster than dial-up". And it's not like we aren't charged the earth for the privilege, either. :(
In fact, your analogy is worse than that. The reason your computer misbehaves is because 1) impure materials, 2) poor or incomplete design, and/or 3) poor or incomplete construction due to your own problem or failure. You'll note that all three are in a big way outside of your control, so you get some cop-out. But, supposedly, none are outside of God's control.
So why does this God, after failing to make me and this world correctly WHICH HE WAS QUITE CAPABLE OF DOING, and thus is HIS OWN DAMN FAULT FOR NOT DOING SO, turn around and BLAME ME and PUNISH ME for what was ultimately HIS MISTAKE? It's disturbingly childish.
You might trot out the "free-will" silliness, but all that does is imply that there is some sort of universal law GREATER THAN God - the law of free will. If not, then ultimately we're back at it all being God's doing, and thus God's fault.
You're right, I'm not equal to God. I'm better than him: I'm less childish, less violent, less misogynistic, and know more about the physical world than he. And I posit that many people on this planet, yourself included, are better than that God, too.
But what if a potential employer (or HR staff, whatever) had done such a search, and found one of your namesake's recipe for crystal meth? You had better hope that employer is smart enough to realise it isn't the same person, but do you honestly believe that?
I've heard stories (on ./ mind you) about companies doing google searches and the like on potential employees, and I can see how an applicant would consider the use of these services, perhaps for some specific reason, or just to clean their google-reputation generally, to get an edge over their competition. What worries me, though, is that employers actually take such searches seriously. The phrase "The internet is serious business" is meant to be a joke, but it seems to go over some people's heads.
I wonder if in the future we'll ever see legislation against discrimination by internet search? Not for a while at least, I posit --- there are probably more deserving unlegislated discriminations to target first.
No, there has to be some sort of classical communication between the two points for the teleportation to work. If the two points are completely isolated from each other, then the last step, a special measurement on B chosen based on the result of the first measurement on A, doesn't make sense.
The neat thing about teleportation is that the state of particle A gets sent over to B (being rough with my description, technically, but it'll do) *without knowing what that state actually is*. The measurement done on A that needs to be sent to B doesn't actually give a complete description of the state, and that's why it will be useful for encryption. But without the result of that measurement the state can't be faithfully teleported to B. There really does have to be an old-fashioned communication channel between the two parties for it to work.
>> You can find trailers and movie reviews online as well to help you decide how to spend your money.
When was the last time you saw a movie trailer that was an accurate representation of the quality of the actual movie?
Sorry, it's not possible to read the teleported state change. The reason is that as soon as you measure particle A without regard to the result of a measurement of particle B the entanglement is practically lost.
You need the joint measurements of A and B in combination (either the result of A determines how B is measured, or vice versa). If you didn't know the result of the first, then you can't be sure how you're supposed to measure the second, and you could well pick the wrong measurement. Then the result will be completely random.
The reason we know it's not bollocks is because after all the measurements there are clear correspondences between the results. If there was no teleportation, these correspondences would be different. If there was no entanglement, there wouldn't be these correspondences at all.
Thus it won't extend to multiple photons like you describe. There are other tricky teleportation schemes using multiple photons, though, like superdense coding which I mentioned in another comment.
Not that it's not understood, or that the maths doesn't make sense, or that nature doesn't fit its predictions, but quantum mechanics is weird, counter-intuitive stuff. Niels Bohr, one of the pioneers of QM: "If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet."
For your first question: I'm not so sure about the fundamental limits there, but the practical limits are improving all the time.
For your second question: yes. It's called Superdense coding. Wikipedia puts it succinctly: Superdense coding is a technique used in quantum information theory to send two bits of classical information using only one qubit, with the aid of entanglement.
Wrong. Completely and utterly wrong. You can't send information faster than the speed of light.
Quantum teleportation doesn't work like that. Here's basically how it works: Two quantum particles are entangled. Then they are separated from each other, one goes to point A the other to B. If you do a measurement on A and COMMUNICATE THE RESULT OF THAT MEASUREMENT to where B is. The other guy can do a special measurement on B based on what A's result was. Then the state of A becomes what the state of B was originally. The particles have not moved (the measurements have changed their states, though), but A's state has been "teleported" to B. It's all to do with the fact that the two particles were entangled in the first place.
But the very important point is that you *still have communicate the result of the first measurement*, which means you're limited to the speed of light.
There is still application for encryption since just knowing what the result of the measurement was is not enough without having the actual entangled particle B.
BUT THERE IS NO APPLICATION TO STAR TREK-LIKE TELEPORTATION OR FASTER THAN LIGHT-SPEED COMMUNICATION. And frankly I'm getting tired of seeing the same wrong information getting played in the media like this. And slashdot even, come on guys, you should know better by now. I'm new here, aren't I?
Yes, IAAQP.
Knowledge of TeX/LaTeX is pretty much a prerequisite in the Maths and Physical Sciences. I'm not so surprised that a CS major missed out. No disrespect, one of my majors was CS, too. It depends on what you typically write, but once you learn LaTeX you might find it hugley more sensible than any WYSIWYG system. I did.
A thousand times yes. Using TeX is standard practice for physics and math papers. Why is it that Nature (not sure about Science) does not accept TeX documents? DOC? Why?
It's probably the fault of the biologists. Silly biologists.
But besides, Nature (again, not sure about Science) takes DOC files that have to be formatted in a certain way that is quite different to what ends up in the journal. They accept PDF like that, too, which is interesting.
This thread is making my head hurt. I think I have to go lie down for a while...
I don't want no *pervert* looking at my nude thumbnail! I'd never live it down!
And now the terrorists have been given an almost automated trigger: detonate after the signal is lost.
Or, if the "jamming" might just be counter-intelligence propaganda and not actually true, use it as a back-up detonation just in case.
Or use a different mechanism entirely.
All this idea does is piss off lots of regular people on their mobile phones as Bush goes past. Would've thought that would be a bad idea...
So, these guys are saying that the act of making an educated guess (which they call "free will"), rather than a concrete logical decision or a complete stab in the dark, is not limited to humans? Nice to know, but I don't find it at all surprising. I mean, if any creature did anything other than make educated guesses they'd be extinct pretty quick. Either because they randomly chose the really stupid option or they took to long to decide.
Oh? I didn't realise. But surely that doesn't mean that a completely quantised representation of the universe would be sufficient. In quantum mechanics continuously variable amplitudes are used to describe superposition states. I don't see how those can be quantised sufficiently without breaking important quantum mechanics like entanglement. Sure, you can't measure an amplitudee without collapsing to some state, but they can be inferred by measurements over populations of identically prepared states.
Or do the Planck units ultimately limit the accuracy of quantum amplitudes, too?
I have a vague feeling this also relates to the Bell inequality, somehow. But now I'm just wondering out loud.
I guess the point I was trying to make here is that just because you can't measure something doesn't necessarily make it equivalent to being quantised. But then, I'm not totally convinced how true that is.
[quote]There are no such thing as analog values in this universe, everything is quantized.[/quote] Absolutely not true. Position is not a quantised value, nor is any of its time derivatives (velocity, acceleration, impulse) and related values (momentum, force, kinetic and potential energy. Time is not quantised. Phase is not quantised, nor wavelength. There's a whole field of physics interested in continuous-variable quantum mechanics. That was a bit silly to say, actually. Perhaps you meant to say that all particles are quantised, but that's a tautology.
I honestly don't like most Simpsons episodes post 2003 at the latest. I was reading the parent and thinking to myself, "Yeah, that might be why."
But then I read the bit about Family Guy. I like Family Guy. So if you're equating the newer Simpsons episodes to Family Guy, I'm not sure what the reason for my distaste is.
Perhaps it's just a general decrease in the wittiness of the Simpsons that has lost me. I recall old episodes seemed much wittier than the new ones. Family Guy has wit too, perhaps less than old Simpsons, but it also has some shock humour that, at least for me, seems make up for that.
I don't know. Perhaps I just got older.
- These lunchbreak pseudophilosophical ramblings brought to you by particles. For that rich quantum-mechanics flavour, choose particles.
kW/h would have to be a measure of the rate of change of a power source. Perhaps as a measure of fluctuation, or something. Not sure how common it is (probably not very) or if another unit of measure is more common, if it is used by anyone at all.
Hi,
If I could just have a moment of your time, are you aware of all the dangers faced by children in society these days? Simple things like colds and scrapes and growing pains, to the frightening reality of paedophiles, child molesters, apathetic parents and abandonment, gangs and violent computer games and widespread pornography on the internet. Don't you think something needs to be done about it all?
I'm asking people to sign this petition I have here. I'm looking for signatures to convince the government to do something about all these problems once and for all. The solution is actually surprisingly simple, but our elected officials don't seem to have realised it, yet. All we have to do is ban children.
Yes, ban children. It's guaranteed to work! Wait, don't go! It'll really work! All you have to do is get rid of all these bloody kids and then you won't have to think of the children ever again, because there won't be any more children to think of! Isn't that wonderful?!
Oh shit, she's getting the cops! *runs*