Ben_Phys618 Posted August 3, 2004 Posted August 3, 2004 One thing that doesn't seem to have been touched (though maybe it has and i didn't see it for all the big scary words) is that if these two particles are in some way mirroring each other, and they can transport the properties of on particle to another, then couldn't you measure these two particles to break the uncertainty principle? Tis says that we cannot know both a particles position and movement, right? If we measure one we have no idea of the other. However, if you measure the position of particle A, and the momentum of particle B, since they are 'entangled,' wouldn't this allow us to overcome uncertainty? (There's probably a flaw there somewhere, but it was worth a try)
5614 Posted August 3, 2004 Author Posted August 3, 2004 ben_phys618: entagled particles mirror each other, if one is rotating at X-speed and Y-angle, so is the other, measure one, and you've effectively measured the others, they're identical, the reason Einstein called this: "scary" or "wierd" or sumin, i cant remember, was coz if u change the rotation of one of the entagled atoms, the other one changed as well, they were always identical, no matter what you did to one, it happened to the other... jordan: what he meant was that he personally couldnt prove to you, right now, that what cap'n said was right, however Einstein did prove Cap'n right, he just couldnt remember that either, so therefore, Cap'n was right, its just he couldnt remember how to prove it to you, other than saying that Einstein proved it.... [and hopefully ud believe in Einstien]
swansont Posted August 3, 2004 Posted August 3, 2004 ben_phys618: entagled particles mirror each other' date=' if one is rotating at X-speed and Y-angle, so is the other, measure one, and you've effectively measured the others, they're identical, the reason Einstein called this: "scary" or "wierd" or sumin, i cant remember, was coz if u change the rotation of one of the entagled atoms, the other one changed as well, they were always identical, no matter what you did to one, it happened to the other... [/quote'] No, I don't think that's right. You don't change that atom's state, you measure it. If you know the state already (i.e. you've done a measurement), and then change it, nothing happens to the other particle, because they are no longer entangled.
TheProphet Posted August 3, 2004 Posted August 3, 2004 No, I don't think that's right. You don't change that atom's state, you measure it. If you know the state already (i.e. you've done a measurement), and then change it, nothing happens to the other particle, because they are no longer entangled. Well dosen't this destroy the whole purpose of using entangled atoms in Computers?? So if this is right there is no real purpose of entangled atoms at all then...
5614 Posted August 3, 2004 Author Posted August 3, 2004 no i think swanston is wrong, [soz] but im sure that if you entagle atoms, then they copy each other, therefore, if u change one, the other one will change as well! thats what entaglement is, that's what it means and does! i mean, im no expert, but that what qunatum entaglement IS.... making atoms mirror each other!
5614 Posted August 3, 2004 Author Posted August 3, 2004 Swansont is a physicist. I'd trust him. oh oooh, better not argue with a physicist on physics, but so what swansont is saying is that, the entagled particles start off the same, but then if you change one, the other wont change? r u certain, im gonna check this out sumwhere else, i get back 2 u lata
5614 Posted August 3, 2004 Author Posted August 3, 2004 ok, so bascially i undertand swansont, he was right, but so was i.... acording to an expert!!!! WOWOWWOWOWOW basically, quantum entaglement makes the atoms or particles, or wtvr, copy each other, change one, the other will change... HOWEVER.... this bond is not strong, change one a lot, and the bond will be broken, thus they are no longer entagled, so only little changes are possible, if you still want the particles to mirror each, [i dont know the scale] SWANSONT WAS RIGHT, THOUGH.... the method used to measure the particles, is considered, by the particles violent!!!!! jokes, thats a bit basic! but the measuring method breaks the "entagle--bond"! if such a word exist, so the bond is broken by measuring, and are no longer entagled.... summary: entagled particles DO copy each other, however only small changes can be made before the bond is broken. if you measure one the bond is broken and they are no longer entagled! [so in a rare case, or actually thinking now, not so rare, two people arguing,... me and swansont, and we were both right!] we werent really arguing, just a disagreement! we're friends now... i hope!
Ben_Phys618 Posted August 4, 2004 Posted August 4, 2004 So my question still stands (I think, if it has been answered, I didn't understand the asnwer) couldn't we measure the momentum of one of the particles, measure the position of the other, since they mirror each other, and break the uncertainity priciple? (as long as the methods with which we measure them with aren't violent). Or have I got it wrong and its just the spin and orientation that is mirrored? Can entangled particles have differing momentums?
TheProphet Posted August 4, 2004 Posted August 4, 2004 So my question still stands (I think, if it has been answered, I didn't understand the asnwer) couldn't we measure the momentum of one of the particles, measure the position of the other, since they mirror each other, and break the uncertainity priciple? (as long as the methods with which we measure them with aren't violent). Or have I got it wrong and its just the spin and orientation that is mirrored? Can entangled particles have differing momentums? If this where possible it might just already have been made.. but i don't know of anyone whom has done it.. Maybe someone else does!? But i Reckon that the ERP (EPR? - Einstein Pdolsky...) paradox still holds for this case too! So answer is No im afraid!
5614 Posted August 4, 2004 Author Posted August 4, 2004 TheProphet is right in this case, entagled particles mirror each other entirely, think of it like this: they start off identical, and they stay identical, [like in a mirror], unless the mirror is broken [by measuring it, or changing one of them drastically], in which case, they stop mirroring each other, they stay on the same original and identical course, coz u havent changed the path or spin or nuthin, only broken the "entagle-link", but then if you change one, the other wont copy it. coz the link has been destroyed!
swansont Posted August 4, 2004 Posted August 4, 2004 summary: entagled particles DO copy each other' date=' however only small changes can be made before the bond is broken.if you measure one the bond is broken and they are no longer entagled! [/quote'] To clarify this - they don't copy each other, per se. You prepare them in a way that they have to have correlated properties. For example, you have a system of two particles, each with spin 1/2. But you know that the total has zero spin, because you prepare the system that way. Now the two particles are entangled - if you separate them without perturbing them too much, they will retain this information. If at some later time you measure the spin of A and you find that it's spin is "up", then you instantly know the other particle, B, is spin "down" even though B might be very far away. However, if after you measure the spin of A you then change its spin, it will have no effect on B.
swansont Posted August 4, 2004 Posted August 4, 2004 So my question still stands (I think, if it has been answered, I didn't understand the asnwer) couldn't we measure the momentum of one of the particles, measure the position of the other, since they mirror each other, and break the uncertainity priciple? (as long as the methods with which we measure them with aren't violent). Or have I got it wrong and its just the spin and orientation that is mirrored? Can entangled particles have differing momentums? Position and momentum aren't properties that can be entangled, AFAIK. Spin (intrinsic angular momentum) is quantized and angular momentum is conserved. I think that you need both properties (quantized, conserved) in order to entangle.
5614 Posted August 4, 2004 Author Posted August 4, 2004 However, if after you measure the spin of A you then change its spin, it will have no effect on B. that is because the measuring process breaks the "entagle-bond" [made up word!] and therefore, they are no longer entagled after the measuring process, there is no longer a link between them, they are like two random atoms, nothing to do with one another
5614 Posted August 4, 2004 Author Posted August 4, 2004 For example, you have a system of two particles, each with spin 1/2. But you know that the total has zero spin, because you prepare the system that way. Now the two particles are entangled - if you separate them without perturbing them too much, they will retain this information. If at some later time you measure the spin of A and you find that it's spin is "up", then you instantly know the other particle, B, is spin "down" even though B might be very far away. so they are inversely proporitional to one another, in a way?
swansont Posted August 4, 2004 Posted August 4, 2004 so they are inversely proporitional to one another, in a way? They have to sum to the same value. Up = +1/2, Down = -1/2, total spin zero.
5614 Posted August 5, 2004 Author Posted August 5, 2004 always??? or can you change thoses values? [reffers to the numeric data from swansont's last post]
swansont Posted August 6, 2004 Posted August 6, 2004 always??? or can you change thoses values? [reffers to the numeric data from swansont's last post] The spin value of a single particle is quantized - an electron can only be spin 1/2. This means it has 1/2 * h/2pi angular momentum (h/2pi = h-bar) If the spin changes, it can only do so in integral values of h-bar, so the electron can have +1/2 or -1/2 value of spin, depending on the direction of the angular momentum vector. Other particles are integral spin. When you start combining particles, you get into the problem of the various ways you can combine the angular momenta and what states are available.
Beholder Posted August 8, 2004 Posted August 8, 2004 Speaking of quantum entanglement and correlation, there is an intriguing experiment that suggests that this correlation and non locality also occurs at our consciousness levels of meditation. I´m skeptical but i always search for new things to wonder if they are possible. Specially when it is apparently experimented and carried out in a very scientifical way. It was made by a mexican scientist and later on repeated and confirmed by an english scientist. Firts time i heard about it was through Amit Goswami, author of Self Aware Universe. Then i search the web and found this http://www.fiu.edu/~mizrachs/quantum-brain.html I found this very impressive. The experiment seems to be very serious and scientifically methodic. Although some skeptics have made some attempts to debunk the experiment, none of them presented any good argument as far as i know. I want to know if any of you have already read anything about that. If so i would be glad to receive some links on the subject. Here is another one, it is also good stuff to read anyway. http://twm.co.nz/subconn_laszlo.html
5614 Posted August 8, 2004 Author Posted August 8, 2004 together, those two articles make up a lot of reading, excuse me, but i havent read all of it, only some of it... indeed it seems very interesting... ive never seen anything like it, heard, but never seen proff, or scientific experiments to prove it...
5614 Posted August 8, 2004 Author Posted August 8, 2004 finally, before this thread, looses all relevance, to what is started about......: what is the difference between: quantum entaglement & quantum teleportation [see: http://www.scienceforums.net/forums/showthread.php?t=4505] i mean, its obvious what the difference is, but i always thought that the processes were similar, in a way. but ive learnt a lot this thread, so i was wondering whether my original thought, or connection between the two was in any way real, or realistic to back up my view, on this website: http://news.bbc.co.uk/2/hi/science/nature/3811785.stm which is a BBC thing on quantum teleportation, it says it uses a method called quantum entaglement, so i made the link. or was the form of teleportation on the BBC link, not quantum teleportation, or basically, what is quantum teleportation? [except thats its a way of teleporting something.....!!] and is it in any way linked to quantum entaglement? is qantum teleportation a certain method, or a name for something which can be done in serveral ways, and one of those is quantum entaglement???
TheProphet Posted August 11, 2004 Posted August 11, 2004 5614: The experiment u reefer to (as i belive was the reason for another thread on the forum). Use Quantum Entagnled atoms to Teleport a Quantum state beetwen to atoms, hence the name Quantum Teleportation. u follow 5614?
5614 Posted August 12, 2004 Author Posted August 12, 2004 5614: The experiment u reefer to (as i belive was the reason for another thread on the forum). Use Quantum Entagnled atoms to Teleport a Quantum state beetwen to atoms, hence the name Quantum Teleportation. u follow 5614? well i think i follow, if you dont mind me saying, i dont think you made yourself entirely clear...... the experiment: used quantum entagled atoms, to teleport a quantum state, between those two atoms, hence the name, quantum teleportation, tell me if one of those lines is incorrect. thats why i did it in steps like that, so its easy to see, where i go wrong [if i do, and i hope i dont] therefore, if this is correct, quantum teleportation ALWAYS uses quantum entalgement, thus making them similar, in a way [but not technically] so my question is, how can entagled atoms, suddenly be able to teleport data, or properties from another? (or is this just one of those things which works, and is too hard to explain!) i find in life, that that is one of the things, which whilst annoying, is true! so i accept it, if thats your answer!
TheProphet Posted August 12, 2004 Posted August 12, 2004 Hmmm, since im swedish i might not be the best at descibing things in english. Therefore i try as best as i can and i always ask to see if the point is gotten or not. Since it might just be my poor english that is at hand. I'll try to describe it to you altough a scheme (ani picture) of this is located in the News section! http://www.scienceforums.net/forums/showthread.php?t=4505 se this one first. Darn se that you have already been in that thread too. First u have the 2 entagled particels. Seperate them and one of them gets under a joint measurment with a state pepared new atom. these two then have the same states which in turn gives the 3rd atom(the other entagnled one) to shift as well hence they are still entangled. So in this way we have teleported a state without sending any informaion. So this is what quantumteleportation is.. But in order for it to work u need quantumly entangled particles =)
5614 Posted August 12, 2004 Author Posted August 12, 2004 Hmmm, since im swedish i might not be the best at descibing things in english. Therefore i try as best as i can and i always ask to see if the point is gotten or not. Since it might just be my poor english that is at hand. no, your english is fine, i havent looked at that diagram properly since a while back, after having been through this thread, and that, and studying the pic for about 5-10mins, now i understand. thanks everyone so quantum teleportation, uses quantum entaglement, although they are not the same thing, so is there a real life practical purpose or use for quantum entaglement? EXCEPT for when you use it to quantum teleport something?
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