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(Live Science)   If this works at any distance, the old "i was on the other side of the galaxy and couldnt get your call" excuse wont ever work again   (livescience.com ) divider line
    More: Cool, space stations, New Journal of Physics, quantum superposition, quantum entanglements, Institute of Physics, color image, action at a distance, photons  
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4516 clicks; posted to Geek » on 09 Apr 2013 at 11:02 AM (3 years ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2013-04-09 10:04:54 AM  
"...the scientists would entangle a pair of light particles, called photons..."


s23.postimg.org
 
2013-04-09 10:20:38 AM  
Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.
 
2013-04-09 10:46:06 AM  
I want my subspace communications smartphone! And where's my flying car?
 
2013-04-09 11:08:42 AM  
images1.wikia.nocookie.net

Has a call for submitter on line 1.
 
2013-04-09 11:09:31 AM  
I don't understand why the would escalate from "small scales in labs on Earth " straight to let's send one into space!  Couldn't they just put one of the entangled particles on a plane and fly it ANYWHERE that is further than the ISS?  The ISS is only 230 miles above us... I could drive to Florida and be 600 miles further than that.
 
2013-04-09 11:13:14 AM  

SmellsLikePoo: I don't understand why the would escalate from "small scales in labs on Earth " straight to let's send one into space!  Couldn't they just put one of the entangled particles on a plane and fly it ANYWHERE that is further than the ISS?  The ISS is only 230 miles above us... I could drive to Florida and be 600 miles further than that.


You think we can "put" light in something? Problem with longer distances becomes the curvature of the Earth, I would imagine. Though gravity is known to bend light, I don't think the Earth's is sufficient to keep it from going for all intents and purposes in a straight line.

All of quantum physics is pretty baffling to me. It seems sometimes the more we learn, the less we find that we know. The wikipedia page on the double slit experiment does put it in layman's terms rather well, but it's still bizarro stuff.
 
2013-04-09 11:17:18 AM  

nekom: Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.


Alice and Bob each have a pair of quantum entangled particles. Bob flies off in his spaceship to prepare the armada for the attack on Planet X. Prior to launching, they synchronize watches, and decide that, at any time after noon on Thursday, Bob will measure his particle. If it has spin 0, the attack is on! If it has spin 1, then there is to be no attack.  Alice, meanwhile, is in negotiations with Planet X's diplomat.
Negotiations, however, break down, so Alice rushes to her interstellar communications team.
"Quick," says Alice, "measure the state of the entangled particle as a 1. Then, Bob's particle will instantly be spin 0, which he'll find out on Thursday at noon! He'll attack, and we'll catch those Planet Xer's with their pants around their slimy lower appendages!"
"Uh..." interjects Charlie, the lead scientist. "The spin state of your particle is random. We can't measure it as a 1. We can just measure it, and maybe it's a 1, and maybe it's not. Bob's particle will be the opposite, but that's it."
"What?!" shrieks Alice. "Can't you zap it with a laser or do something to force it into a 1?! This is crucial to our attack plan, you nerd!"
"Sorry, no," explains Charlie. "We can force it into spin 1, sure, but that will break the entanglement. Bob's particle will then randomly be a 1 or a 0. There's no way of letting him know, other than an old fashioned light speed communication."
"You suck, and Einstein sucks," sulks Alice.
 
2013-04-09 11:18:39 AM  
"According to quantum physics, entanglement is independent of distance," physicist Rosalind Lutece said in a statement.
 
2013-04-09 11:20:43 AM  

nekom: Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.


It's been a while since I took Q-mech and had this explained, but I'll try my best!

If I remember correctly:

Basically, what's entangled are the *waveforms* of the particles: That is, when you measure one particle, you know what the other particle 'has' to be, so it's wave form also collapses.

Think-... Okay. You know the schrodinger's cat thought experiment? How according to the thought experiment, the cat is neither alive NOR dead until you open the box and 'observe' it?
 (Or if the outside universe interacts with the cat in any fashion?) It instead, exists in this sort of un-determined super-position of *both* states.1

Okay, we're going to modify the experiment now. Now, it's two boxes that are linked. If the poison vial doesn't go off in one box, it WILL in the other.

Until we open the box, both cats are in a super-position state: They are both alive *and* dead at the same time.

Now, I open my box. I see that my cat is alive! Thus, I know the cat in the other box *must* be dead-so I have collapsed it's wave form. As *soon* as I open my box, neither cat exists in a super-position state: They exist as either alive *or* dead. Even if I never open the other box.

However! Nothing I do to the cat in my box will affect the cat in the other box. If I kill the cat in my box, it will not bring the cat in the other box to life.

It's like that with particles, too. If two particles are entangled, we can't (as far as we know) fiddle with one and affect what happens to the other one. We can just instantly 'know' what the other one is once we measure one of them. So you can't transmit data by, say, messing with the spin of the particles you have.

Also, there's no real way to measure 'whether' a waveform's collapsed or not (if I remember right), so you can't transmit data that way, either.

I hope that helps some!


1) For clarifiaction, the schroedinger's cat thought experiment was initially designed to show how the super-position interpretation of quantum mechanics HAD to be wrong, because clearly the cat couldn't be in two states at once. Turns out that, no, the super-position interpretation IS right.2
2) But won't really work with macroscopic objects. You can't make quantum entangled cats, I'm just using them for the purpose of a metaphor.
 
2013-04-09 11:22:00 AM  

Theaetetus: Alice and Bob each have a pair of quantum entangled particles. Bob flies off in his spaceship to prepare the armada for the attack on Planet X. Prior to launching, they synchronize watches, and decide that, at any time after noon on Thursday, Bob will measure his particle. If it has spin 0, the attack is on! If it has spin 1, then there is to be no attack. Alice, meanwhile, is in negotiations with Planet X's diplomat.


Dang it I need to type about cats faster.
 
2013-04-09 11:22:08 AM  

Theaetetus: nekom: Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.

Alice and Bob each have a pair of quantum entangled particles. Bob flies off in his spaceship to prepare the armada for the attack on Planet X. Prior to launching, they synchronize watches, and decide that, at any time after noon on Thursday, Bob will measure his particle. If it has spin 0, the attack is on! If it has spin 1, then there is to be no attack.  Alice, meanwhile, is in negotiations with Planet X's diplomat.
Negotiations, however, break down, so Alice rushes to her interstellar communications team.
"Quick," says Alice, "measure the state of the entangled particle as a 1. Then, Bob's particle will instantly be spin 0, which he'll find out on Thursday at noon! He'll attack, and we'll catch those Planet Xer's with their pants around their slimy lower appendages!"
"Uh..." interjects Charlie, the lead scientist. "The spin state of your particle is random. We can't measure it as a 1. We can just measure it, and maybe it's a 1, and maybe it's not. Bob's particle will be the opposite, but that's it."
"What?!" shrieks Alice. "Can't you zap it with a laser or do something to force it into a 1?! This is crucial to our attack plan, you nerd!"
"Sorry, no," explains Charlie. "We can force it into spin 1, sure, but that will break the entanglement. Bob's particle will then randomly be a 1 or a 0. There's no way of letting him know, other than an old fashioned light speed communication."
"You suck, and Einstein sucks," sulks Alice.


Alice and Bob find themselves in the most unusual circumstances.
 
2013-04-09 11:22:56 AM  

SmellsLikePoo: I don't understand why the would escalate from "small scales in labs on Earth " straight to let's send one into space!  Couldn't they just put one of the entangled particles on a plane and fly it ANYWHERE that is further than the ISS?  The ISS is only 230 miles above us... I could drive to Florida and be 600 miles further than that.


IF you read the article a big part of this test entangling the particles on earth then shooting one particle to the IIS, before collapsing them. You need line of sight for that (though its been done with fiber optics as well).
 
2013-04-09 11:25:25 AM  

Felgraf: nekom: Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.

It's been a while since I took Q-mech and had this explained, but I'll try my best!

If I remember correctly:

Basically, what's entangled are the *waveforms* of the particles: That is, when you measure one particle, you know what the other particle 'has' to be, so it's wave form also collapses.

Think-... Okay. You know the schrodinger's cat thought experiment? How according to the thought experiment, the cat is neither alive NOR dead until you open the box and 'observe' it?
 (Or if the outside universe interacts with the cat in any fashion?) It instead, exists in this sort of un-determined super-position of *both* states.1

Okay, we're going to modify the experiment now. Now, it's two boxes that are linked. If the poison vial doesn't go off in one box, it WILL in the other.

Until we open the box, both cats are in a super-position state: They are both alive *and* dead at the same time.

Now, I open my box. I see that my cat is alive! Thus, I know the cat in the other box *must* be dead-so I have collapsed it's wave form. As *soon* as I open my box, neither cat exists in a super-position state: They exist as either alive *or* dead. Even if I never open the other box.

However! Nothing I do to the cat in my box will affect the cat in the other box. If I kill the cat in my box, it will not bring the cat in the other box to life.

It's like that with particles, too. If two particles are entangled, we can't (as far as we know) fiddle with one and affect what happens to the other one. We can just instantly 'know' what the other one is once we measure one of them. So you can't transmit data by, say, messing with the spin of the particles you have.

Also, there's no real way to measure 'whether' a waveform's collapsed or not (if ...


My cat's breath smells like cat food.
 
2013-04-09 11:27:43 AM  

nekom: SmellsLikePoo: I don't understand why the would escalate from "small scales in labs on Earth " straight to let's send one into space!  Couldn't they just put one of the entangled particles on a plane and fly it ANYWHERE that is further than the ISS?  The ISS is only 230 miles above us... I could drive to Florida and be 600 miles further than that.

You think we can "put" light in something? Problem with longer distances becomes the curvature of the Earth, I would imagine. Though gravity is known to bend light, I don't think the Earth's is sufficient to keep it from going for all intents and purposes in a straight line.

All of quantum physics is pretty baffling to me. It seems sometimes the more we learn, the less we find that we know. The wikipedia page on the double slit experiment does put it in layman's terms rather well, but it's still bizarro stuff.


Yeah, good call... I didn't read the experiment very carefully.  Although, how you would capture the photon on the ISS for any sort of analysis is WAY beyond me.  They say they would send the one to the ISS then modify or somehow change the one on earth and look for the same adjustment on the ISS... I don't see how they would capture a photon to measure the change?
 
2013-04-09 11:32:09 AM  

SmellsLikePoo: I don't see how they would capture a photon to measure the change?


images.samys.com
What a photon capturing device may look like.
 
2013-04-09 11:37:13 AM  

SmellsLikePoo:
Yeah, good call... I didn't read the experiment very carefully.  Although, how you would capture the photon on the ISS for any sort of analysis is WAY beyond me.  They say they would send the one to the ISS then modify or somehow change the one on earth and look for the same adjustment on the ISS... I don't see how they would capture a photon to measure the change?


That one beats the hell out of me as well. Maybe they attempt to measure the photon when it hits, in a stream. Maybe they somehow get it into a magnetic field. Maybe probably aliens.

I just always get a little pissed (no clue why I take it personally) that such a thing exists, yet due to its nature, we are unable to exploit it as a means of instant communication. That would be handy! Violates causality though, I have been told. i.e. you would be able to send a message which you would receive before you sent it. I don't have a very deep understanding of it.
 
2013-04-09 11:52:02 AM  

SmellsLikePoo: nekom: SmellsLikePoo: I don't understand why the would escalate from "small scales in labs on Earth " straight to let's send one into space!  Couldn't they just put one of the entangled particles on a plane and fly it ANYWHERE that is further than the ISS?  The ISS is only 230 miles above us... I could drive to Florida and be 600 miles further than that.

You think we can "put" light in something? Problem with longer distances becomes the curvature of the Earth, I would imagine. Though gravity is known to bend light, I don't think the Earth's is sufficient to keep it from going for all intents and purposes in a straight line.

All of quantum physics is pretty baffling to me. It seems sometimes the more we learn, the less we find that we know. The wikipedia page on the double slit experiment does put it in layman's terms rather well, but it's still bizarro stuff.

Yeah, good call... I didn't read the experiment very carefully.  Although, how you would capture the photon on the ISS for any sort of analysis is WAY beyond me.  They say they would send the one to the ISS then modify or somehow change the one on earth and look for the same adjustment on the ISS... I don't see how they would capture a photon to measure the change?


actually using lasers and magnets, they've been able to pause light beams for a while now.

though i don't think the setup is anything near portable, that would be kind of cool, to ship light long distance like that.

'the freshest photons, reflected off the mountaintop in the early morning', sort of marketing.
 
2013-04-09 11:54:13 AM  

buttery_shame_cave:
'the freshest photons, reflected off the mountaintop in the early morning', sort of marketing.


Artisan photons? PLEASE don't give the hipsters any more ideas!
 
2013-04-09 12:02:20 PM  
So if a change at one side affects the other side why not create an up and down position. Then what exactly stops morse code?
 
2013-04-09 12:09:04 PM  

Zyme: So if a change at one side affects the other side why not create an up and down position. Then what exactly stops morse code?


Theaetetus:
Alice and Bob each have a pair of quantum entangled particles. Bob flies off in his spaceship to prepare the armada for the attack on Planet X. Prior to launching, they synchronize watches, and decide that, at any time after noon on Thursday, Bob will measure his particle. If it has spin 0, the attack is on! If it has spin 1, then there is to be no attack.  Alice, meanwhile, is in negotiations with Planet X's diplomat.
Negotiations, however, break down, so Alice rushes to her interstellar communications team.
"Quick," says Alice, "measure the state of the entangled particle as a 1. Then, Bob's particle will instantly be spin 0, which he'll find out on Thursday at noon! He'll attack, and we'll catch those Planet Xer's with their pants around their slimy lower appendages!"
"Uh..." interjects Charlie, the lead scientist. "The spin state of your particle is random. We can't measure it as a 1. We can just measure it, and maybe it's a 1, and maybe it's not. Bob's particle will be the opposite, but that's it."
"What?!" shrieks Alice. "Can't you zap it with a laser or do something to force it into a 1?! This is crucial to our attack plan, you nerd!"
"Sorry, no," explains Charlie. "We can force it into spin 1, sure, but that will break the entanglement. Bob's particle will then randomly be a 1 or a 0. There's no way of letting him know, other than an old fashioned light speed communication."
"You suck, and Einstein sucks," sulks Alice.
 
2013-04-09 12:13:00 PM  

Theaetetus: nekom: Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.

Alice and Bob each have a pair of quantum entangled particles. Bob flies off in his spaceship to prepare the armada for the attack on Planet X. Prior to launching, they synchronize watches, and decide that, at any time after noon on Thursday, Bob will measure his particle. If it has spin 0, the attack is on! If it has spin 1, then there is to be no attack.  Alice, meanwhile, is in negotiations with Planet X's diplomat.
Negotiations, however, break down, so Alice rushes to her interstellar communications team.
"Quick," says Alice, "measure the state of the entangled particle as a 1. Then, Bob's particle will instantly be spin 0, which he'll find out on Thursday at noon! He'll attack, and we'll catch those Planet Xer's with their pants around their slimy lower appendages!"
"Uh..." interjects Charlie, the lead scientist. "The spin state of your particle is random. We can't measure it as a 1. We can just measure it, and maybe it's a 1, and maybe it's not. Bob's particle will be the opposite, but that's it."
"What?!" shrieks Alice. "Can't you zap it with a laser or do something to force it into a 1?! This is crucial to our attack plan, you nerd!"
"Sorry, no," explains Charlie. "We can force it into spin 1, sure, but that will break the entanglement. Bob's particle will then randomly be a 1 or a 0. There's no way of letting him know, other than an old fashioned light speed communication."
"You suck, and Einstein sucks," sulks Alice.


How does that square with this statement from the article? "Spooky" quantum entanglement connects two particles so that actions performed on one reflect on the other.
 
2013-04-09 12:18:52 PM  
They're probably kicking research into high gear now so they can coordinate the release of the ansible technology with the Ender's Game premiere.
 
2013-04-09 12:29:11 PM  

stevetherobot: Theaetetus: nekom: Ah yes the old double slit experiment.  Too bad it can't actually be used to transmit information*.

* I don't know WHY, so don't ask me, but someone I trust to know explained it to me, I didn't understand it but he was a credible source.

Alice and Bob each have a pair of quantum entangled particles. Bob flies off in his spaceship to prepare the armada for the attack on Planet X. Prior to launching, they synchronize watches, and decide that, at any time after noon on Thursday, Bob will measure his particle. If it has spin 0, the attack is on! If it has spin 1, then there is to be no attack.  Alice, meanwhile, is in negotiations with Planet X's diplomat.
Negotiations, however, break down, so Alice rushes to her interstellar communications team.
"Quick," says Alice, "measure the state of the entangled particle as a 1. Then, Bob's particle will instantly be spin 0, which he'll find out on Thursday at noon! He'll attack, and we'll catch those Planet Xer's with their pants around their slimy lower appendages!"
"Uh..." interjects Charlie, the lead scientist. "The spin state of your particle is random. We can't measure it as a 1. We can just measure it, and maybe it's a 1, and maybe it's not. Bob's particle will be the opposite, but that's it."
"What?!" shrieks Alice. "Can't you zap it with a laser or do something to force it into a 1?! This is crucial to our attack plan, you nerd!"
"Sorry, no," explains Charlie. "We can force it into spin 1, sure, but that will break the entanglement. Bob's particle will then randomly be a 1 or a 0. There's no way of letting him know, other than an old fashioned light speed communication."
"You suck, and Einstein sucks," sulks Alice.

How does that square with this statement from the article? "Spooky" quantum entanglement connects two particles so that actions performed on one reflect on the other.


You need to account for this further statement:
"Journalists suck."
 
2013-04-09 12:39:00 PM  

stevetherobot: "Spooky" quantum entanglement connects two particles so that actions performed on one reflect on the other.


Because the people who wrote it don't understand how quantum entanglement works.

The 'connection' is that if you measure/collapse the wave form of one, you measure/collapse the wave form of the other, but you can't *ALTER* how that measurement is going to turn out.
 
2013-04-09 12:50:00 PM  

Felgraf: stevetherobot: "Spooky" quantum entanglement connects two particles so that actions performed on one reflect on the other.

Because the people who wrote it don't understand how quantum entanglement works.

The 'connection' is that if you measure/collapse the wave form of one, you measure/collapse the wave form of the other, but you can't *ALTER* how that measurement is going to turn out.


Which means that while it is absolutely INCREDIBLE that two particles, no matter how far away have a direct effect on each other, the effect is not controllable, totally random. What a pisser.

One of the things that's helping me understand this a bit is that photons are going at light speed, and as such are not experiencing the passage of time. Which in itself is also pretty "spooky", along with the rest of quantum stuff.
 
2013-04-09 12:54:40 PM  
This is an easy analogy for quantum entanglement:
I have $100 in singles, and I have someone put a random amount in one wallet and the remaining amount in another wallet. I give you one wallet, and you fly across the country. Neither of us knows exactly how much is in our wallet, so accordingly, each wallet is in an indeterminate state. However, we both know explicitly that the total money is $100 and that must be conserved, because I strip searched the someone afterwards to make sure they weren't hiding any singles.
At some random point, I open my wallet and see it has $72. Your wallet must have $28 in it, by the law of conservation of total money and because you didn't buy any drinks on the plane. I know this to be true, even if you haven't actually looked in your wallet yet. But I can't communicate that amount to you, nor can I change it.

Except that the wallets are particles, the money is spin state, and the law is conservation of energy. But you do have to strip search a scientist to be sure they're not smuggling particles.
 
2013-04-09 01:15:02 PM  

Theaetetus: This is an easy analogy for quantum entanglement:
I have $100 in singles, and I have someone put a random amount in one wallet and the remaining amount in another wallet. I give you one wallet, and you fly across the country. Neither of us knows exactly how much is in our wallet, so accordingly, each wallet is in an indeterminate state. However, we both know explicitly that the total money is $100 and that must be conserved, because I strip searched the someone afterwards to make sure they weren't hiding any singles.
At some random point, I open my wallet and see it has $72. Your wallet must have $28 in it, by the law of conservation of total money and because you didn't buy any drinks on the plane. I know this to be true, even if you haven't actually looked in your wallet yet. But I can't communicate that amount to you, nor can I change it.

Except that the wallets are particles, the money is spin state, and the law is conservation of energy. But you do have to strip search a scientist to be sure they're not smuggling particles.


What bothers me by all this is the scientist INSIST that at the moment of entanglement that the final spin (amount of money) isn't set. They insist that the final spin is truly random and only set when you collapse it. It still refuse to believe this.
 
2013-04-09 01:22:23 PM  

MindStalker: Theaetetus: This is an easy analogy for quantum entanglement:
I have $100 in singles, and I have someone put a random amount in one wallet and the remaining amount in another wallet. I give you one wallet, and you fly across the country. Neither of us knows exactly how much is in our wallet, so accordingly, each wallet is in an indeterminate state. However, we both know explicitly that the total money is $100 and that must be conserved, because I strip searched the someone afterwards to make sure they weren't hiding any singles.
At some random point, I open my wallet and see it has $72. Your wallet must have $28 in it, by the law of conservation of total money and because you didn't buy any drinks on the plane. I know this to be true, even if you haven't actually looked in your wallet yet. But I can't communicate that amount to you, nor can I change it.

Except that the wallets are particles, the money is spin state, and the law is conservation of energy. But you do have to strip search a scientist to be sure they're not smuggling particles.

What bothers me by all this is the scientist INSIST that at the moment of entanglement that the final spin (amount of money) isn't set. They insist that the final spin is truly random and only set when you collapse it. It still refuse to believe this.


Eppur si muove.

Specifically, you know that it's not set until you measure it, because otherwise you wouldn't get the interference patterns seen in the double slit experiment: it must be a wave of statistical probabilities in order that it can interfere with itself. If it were already set, and you just happened to not know the value, you'd simply get two spots on the wall.
 
2013-04-09 01:22:59 PM  

MindStalker: What bothers me by all this is the scientist INSIST that at the moment of entanglement that the final spin (amount of money) isn't set. They insist that the final spin is truly random and only set when you collapse it. It still refuse to believe this.


They insist this because, at the very least, there is experimental proof that there is not *local* hidden variable.

This has actually been *experimentally proven*. While there could be a non-local hidden variable, it's currently considered more likely that, yes, it's truly random.

Let me dig up the experiment.

Here we go!

Bell's Inequality expriment:
Basically, it proves that what we consider to be 'classical' physics (local realism) CANNOT be true at the quantum level (if it were true, there would have to be a 'local hidden variable', some variable that we haven't yet 'seen' that produces the apparent randomness. IF it were deterministic, there would be a 'variable' behind it).

http://en.wikipedia.org/wiki/Bell_test_experiments

Basically: Classical physics does not function at the quantum level. This is proven. Now, the experiment DOESN'T necessarily prove it's actual randomness. Their could be a 'non-local' hidden variable. But this would require a variable that is able of affecting things at (I think) faster-than-light speeds.

Basically, we have *TESTED* this shiat, and currently randomness is the best explanation we've got.
 
2013-04-09 01:24:36 PM  

Theaetetus: Specifically, you know that it's not set until you measure it, because otherwise you wouldn't get the interference patterns seen in the double slit experiment: it must be a wave of statistical probabilities in order that it can interfere with itself. If it were already set, and you just happened to not know the value, you'd simply get two spots on the wall.


Well, to be fair, I think technically hidden variable theories would also allow for that to happen? I can't recal, we didn't spend *too* much time on them, since they currently have little support.
 
2013-04-09 01:30:51 PM  

Felgraf: http://en.wikipedia.org/wiki/Bell_test_experiments

Basically: Classical physics does not function at the quantum level. This is proven. Now, the experiment DOESN'T necessarily prove it's actual randomness. Their could be a 'non-local' hidden variable. But this would require a variable that is able of affecting things at (I think) faster-than-light speeds.


That one's a bit dense for the layman. Try this. Basically, you set up a system with an input laser, a beam splitter, two mirrors, another beam splitter, and two detectors:
www.rpi.edu
Half of the light goes to detector U, half goes to D. Pretty straight forward.
Now, since it's all single-frequency light, you can move one mirror by half a wave length, so that it's path is slightly longer:
www.rpi.edu
And as a result, the light going to one detector will be completely canceled, and the light going to the other is doubled:
www.rpi.edu
Great, easy. Light's a wave. No problem. But wait, this still works, even if you're shooting out single photons. You fire them one at a time, and they  always go to the upper detector. But that can't work, unless they can interfere with the previously-sent or subsequently-sent photons!

And then it gets weirder... You put a detector in the path so that you can tell whether the photon went up or down...
www.rpi.edu
And suddenly it's 50% up and 50% down. Even if you're still shooting out one photon at a time. Merely by looking, you destroy the interference and the system acts like you're shooting ping pong balls instead of waves.
 
2013-04-09 01:33:59 PM  

Theaetetus: You need to account for this further statement:
"Journalists suck."


I love coming into threads like this and finding that the usual questions have already been correctly answered.
 
2013-04-09 01:45:52 PM  
ic.pics.livejournal.com
 
2013-04-09 01:53:47 PM  
You know there are times when I think I'm a relatively smart person.  Then I read about stuff like this and realize have no clue what is going on in the world around me.
 
2013-04-09 02:09:33 PM  

Frozboz: You know there are times when I think I'm a relatively smart person.  Then I read about stuff like this and realize have no clue what is going on in the world around me.


This isn't the sort of thing a layman can truly understand, I don't think. Except of course the vague concepts. That's where I am, I am vaguely aware of some of the quantum mechanics. I believe without a full physics education (which I have no plans to ever seek), that is where I shall forever remain. It's just not the kind of thing any "jack of all trades" can grasp, it's a shiatpot full of math, conflicting theories, things that make NO sense when your mind is in classical physics, and this is just the tip of the iceberg. Even on the non-quantum level, chemistry is really farking bizarre. I'm an avid fan of the "crash course" series on youtube, which I highly recommend, they are currently doing chemistry and American history, though they have dozens of others on Biology, Ecology, etc. The more I fish around in chemistry the more I realize how utterly LITTLE I really knew about it.

The properties of super-cooled helium are up there as well. The truth is stranger than fiction, and science is a BIZARRE reality show.
 
2013-04-09 02:13:28 PM  
Meanwhile, religion was still trying to prove the Shroud of Turin was real.
 
2013-04-09 02:34:47 PM  
I'm surprised the space hater isn't here shiatting on this. "why do you need to call space, its a fantasy for you dumb ppl!"
 
2013-04-09 02:36:00 PM  

MindStalker: What bothers me by all this is the scientist INSIST that at the moment of entanglement that the final spin (amount of money) isn't set. They insist that the final spin is truly random and only set when you collapse it. It still refuse to believe this.


Obviously you are in good company - for example Schrodinger, at least at the point he created his famous Cat thought experiment, although I seem to recall he was convinced it worked that way later on (although it has been a while since I learned the history of QM)
 
2013-04-09 04:31:43 PM  

Frozboz: You know there are times when I think I'm a relatively smart person.  Then I read about stuff like this and realize have no clue what is going on in the world around me.


Summed up best (as most things are) by Feynman: "if you think you understand quantum mechanics, you don't understand quantum mechanics"
 
2013-04-09 04:46:14 PM  

Theaetetus: And then it gets weirder... You put a detector in the path so that you can tell whether the photon went up or down...
www.rpi.edu
And suddenly it's 50% up and 50% down. Even if you're still shooting out one photon at a time. Merely by looking, you destroy the interference and the system acts like you're shooting ping pong balls instead of waves.


One slight point, as I understand it, the detector itself doesn't change the output. It has to be making a measurement. If the detector is turned off, you still get the interference pattern. Turning it on and making an observation removes the interference. By this means, it seems to me, information can be transmitted, possibly faster than light.

For example, you set up your experiment using much larger distances. Set your interference cancelling detector near the source of the beam, lets call it detector I. Now put U and D detectors some miles away.

When you turn on your beam the scientists at U & D see photons striking only the U detector as you described. You then turn on the I detector and, also as you described, U & D instantly see the interference pattern disappear.

The Scientists at U & D know instantly when you turned on the I detector. That's a bit of information transmitted from you to them. In principle, you could use such a method to send a string of bits by turning the I detector on an off couldn't you? Crude, yes, but it would be proof of concept.

Now, having said that, I'm probably wrong and I look forward to reading about why. :)

/ I've long felt QM disproves the existence of an omniscient God
// If he knows everything then he's observing everything
/// A universe with an omniscient being can't have particles in superposition
//// Yes, I may have smoked too much weed in college
 
2013-04-09 05:00:05 PM  
As long as Bob Bean doesn't tell Alice Andrew about this Ansible there is no problem.
 
2013-04-09 05:07:09 PM  

Boddhisatva: When you turn on your beam the scientists at U & D see photons striking only the U detector as you described. You then turn on the I detector and, also as you described, U & D instantly see the interference pattern disappear.

The Scientists at U & D know instantly when you turned on the I detector.


The photons en-route to U&D didn't pass through my detector. The scientists at U&D won't see the interference pattern vanish until the latest batch of photons arise- which limits the speed of the signal to light speed, which is what we'd expect.
 
2013-04-09 08:10:17 PM  

Boddhisatva: I've long felt QM disproves the existence of an omniscient God


The real kicker is the fact that through QM we can get a universe that self creates.....


Also you are wrong unfortunately I'm not smart enough to know why but I would guess it's the fact that you can't turn the detector "on" or "of" if you put the measurement system in place it will effect the result whether you look at it or not.

/not smart
//tried to be but dropped out of physics grad school
///wish I hadn't
///I like scotch
 
2013-04-10 06:23:35 AM  
I'm grateful they are doing this on the ISS, because there is nowhere on earth where they could separate two particles by 500 km. Yay, science!
 
2013-04-10 08:06:12 AM  

Macular Degenerate: I'm grateful they are doing this on the ISS, because there is nowhere on earth where they could separate two particles by 500 km. Yay, science!


This is a line of sight experiment. You're not going to get a 500km line of sight anywhere on earth.
 
2013-04-10 09:37:58 AM  

ghall3: Boddhisatva: I've long felt QM disproves the existence of an omniscient God

The real kicker is the fact that through QM we can get a universe that self creates.....


Also you are wrong unfortunately I'm not smart enough to know why but I would guess it's the fact that you can't turn the detector "on" or "of" if you put the measurement system in place it will effect the result whether you look at it or not.

/not smart
//tried to be but dropped out of physics grad school
///wish I hadn't
///I like scotch


Part of the problem comes with how scientists/physicists use the word 'observe' when it comes to, say, q mech, versus how it is NORMALLY used.

When scientists say 'observed', with regard to qmech, they really just mean  "Interacts with anything else", since that interaction could be measured/observed.

It does not mean a person/living animal looking at it.
 
2013-04-10 11:19:29 AM  

Boddhisatva: The Scientists at U & D know instantly when you turned on the I detector. That's a bit of information transmitted from you to them. In principle, you could use such a method to send a string of bits by turning the I detector on an off couldn't you? Crude, yes, but it would be proof of concept.

Now, having said that, I'm probably wrong and I look forward to reading about why. :)


Sure - that one doesn't have anything to do with quantum entanglement, and all of the communication is occurring at light speed (or less)... Consider, the scientists at U&D don't know  instantly when you turned on the I detector... they only know once those photons are transmitted past the detector and received and either land consistently at one detector, or show up at both, and that's going to take (a) the transit time of the photon, and (b) the transit times of  multiple photons so they can be statistically sure that they're not just landing at the one detector by chance.
In other words, at  best, that communication happens at light speed, and in practice much slower. ;)
 
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