# Quatuam entanglement

1. Dec 21, 2004

### Kaluence

is it possible to move the quantum state of individual atoms from one location to another using the principal of quantuam entanglement

2. Dec 21, 2004

### dextercioby

What do u mean "move the quantum state"?????? Quantum states are vectors in an abstract Hilbert space.They evolve with time,they ar not cars or furniture to be "moved",and similar "transfered". :tongue2: U can move atoms,o actually they move themselves,but that's another story:"atom" is something real,while "vector in a Hilbert space" is merely a mathematical abstraction...

Daniel.

PS.What is the principle of quantum entaglement???I've never heard of it before.Has it been added to the famous 6,sincei haven't opened the QM course taught in school???? Hopefully not. :tongue2:

3. Dec 21, 2004

### dextercioby

For quantum systems made up of identical particles,u can switch uniparticle states among particles or switch particles among uniparticle states.But that's something totally different and still doesn't involve "move(ing) the quantum state from one location to another".The Hilbert space of states is an abstract one,it's not an euclidian one.In an euclidian space u can "move" vectors:parallel displacemets,rotations,angles between vectors,...But vectors like $|\psi>$ cannot be "moved".

Daniel.

4. Dec 21, 2004

### caribou

There is "quantum teleportation" but I haven't read enough about it to know much. Have a look at this article, particularly the diagram at the bottom for something which fits what you are asking about:

http://news.bbc.co.uk/2/hi/science/nature/3811785.stm

5. Dec 22, 2004

### Louis Cypher

Qm Entanglement

Posted this on another forum and they just deleted it and wouldn't respond to my questions so I'm assuming it's nonsense, what I wanted too know though is why it's nonsense, to help me learn a bit more about qm; after reading an article on qbits and how they can use entanglement to check parity in a different way so that q information doesnt become lost by observation I had the thought if we entangle a photon and then observe the two photons entangled state a computer could take this information via observing another entangle photon, and do it computationally to check the quantum or just use error bit from then on any information that computer and the other chose to send quantumly would instantaneously be transfereed wireless without broadband information exchange at insatantaneous speed; the applications of the idea are endles, why is this wrong, please answer?!? I'm dying to know.

thanks

Last edited: Dec 22, 2004
6. Dec 22, 2004

### Louis Cypher

Scientists belive they have quantumly transported a hydrogen ion or just a proton by using quantum entanglement, there not sure though but it should in theory be possible to transport atoms, beam me up scotty:-)

7. Dec 22, 2004

### ZapperZ

Staff Emeritus
I suggest you stop reading supermarket tabloids for your physics news sources. There has been NO SUCH reports. Do NOT confuse "quantum teleportation" with the teleportation you see in Star Trek movies.

Zz.

8. Dec 22, 2004

### Louis Cypher

Ah sense of humour by pass; was it painfull? that was meant to be a joke, matter transportation and the transfer of an ion are two different things, by a quantum leap, try to develope a sense of humor I think;-)

O.k. since it's pedants corner day, essentially by getting two photons to interact with each other they become entangled, that is there spins or polorization becomes identicle, if we then take particle a and send it to a location 4 miles away and particle b to another location four miles away, total 8 miles, if we observe one spin quantumly i.e change its spin the other one insantly becomes the same spin it transfers this information instantly regardless of distance, so wether i was in china or on the other side of the universe distance is irrelevant. If you know the original spin then you can use this bizzare property to send almost uncrackable code by using the photons as qbits Qunatum bits to represent 1 and 0, if the message is intercepted it becomes nonsense, so in theory it's uncrackable at least from interception because the two people communicating know the original state each individual photon can be repolarised according to a preset key.

Thus the idea behind quantum computing qbita because they can be both 1 and 0 would increase processing speed, a hundred thousand qbits would increase speed by a factor of 2^1000, it is the holy grail of particle physics reasearch at the moment but who knows in twenty years or so?

9. Dec 22, 2004

### Louis Cypher

Oh and it's there have been not has

10. Dec 22, 2004

### DaveC426913

Is it possible to replicate a quantum state in one place based on a quantum state in another place. This is the quantum teleportation that has been achieved. They did this experiment across the Thames R.

The media has taken the word 'teleportation' and blown it up to Star Trekkian proportions.

Here's an article that briefly covers it.
http://www.geocities.com/grymse/quantum.html

"PS.What is the principle of quantum entaglement???I've never heard of it before.Has it been added to the famous 6,sincei haven't opened the QM course taught in school???? "

This is a very strange statement. It is hard to imagine exploring quantum mechanics at all without tripping over quantum entanglement. It would be like saying I've studied Einsten's relativity but I don't know what a space-time continuum is.

11. Dec 22, 2004

### Louis Cypher

teleportation

essentially its making an exact copy of a hydrogen ion rather than teleportation per se.

12. Dec 22, 2004

### Hans de Vries

I'm glad to hear you say this but you might be equally critical on
people like Zeilinger as well.

Zeilinger articles (from his site):

Quantum Teleportation, on the cover of "Scientific American"
(Shows people commuting by teleportation both on the cover
and in the article)

Science fact: Scientists achieve 'Star Trek'-like feat, featured by CNN SCI-TECH"

He puts the words in the mouth of science fictions writers while
taking a more careful approach himself. However he does love to
leave these kind of Star Trek impressions with the general public.

Also the claim that Heisenberg's principle can be circumvented
and the referral to the "Heisenberg compensator" in Star Trek
that makes teleportation possible....

The Heisenberg circumvention claim presumes that both position
and momentum (cq. time/energy) are still 100% accurately available
somewhere but somehow we can not measure them both accurately
at the same time.

He then goes on that both can be teleported accurately at the
same time with this Heisenberg Circumvention trick.

This idea that both (position and momentum) must be still there
accurately is also what is claimed in the original EPR and Bell
papers. It's this what leads to the hidden variables idea. (we can't
see them but they must still be there) The EPR and Bell papers
however do not represent Quantum Mechanics.

One can not deny and acknowledge hidden variables at the same time
like it's done in these articles.

Regards, Hans

13. Dec 22, 2004

### ZapperZ

Staff Emeritus
To be fair to Zeilinger (and I have heard his talk a couple of times on this), he never mentioned anything resembling the teleportation of objects. In fact, I've seen him tried to explain a few times that it is only the information of states that are being "teleported" in such experiments. Popular media, on the other hand, often like to sensationalize such things. That is how we get people who don't know any better thinking we now are able to teleport a cow. It doesn't help that people within this field helped in creating the misinformation by calling this "quantum teleportation".

Zz.

14. Dec 22, 2004

### Louis Cypher

You're right of course, but the only way to bring QM into public thinking is to KISS, so we need to exagerate thus NS and SAm else we endanger alienating the public by complicating the simple truths, so what if they think they can teleport matter as large as a cow, at least there interested?

Or have I missed the point?

15. Dec 22, 2004

### Louis Cypher

That's why we have theories like strings because people make conjecture on assumptions, it's philosophy but it should not be discouraged, after all weren't Einstein and Schrodinger once considered philosophers?

16. Dec 22, 2004

### TheDonk

I agree with you, Louis Cypher, that it isn't bad to talk about far away and unlikely possibilities, but saying that we already did them is bad.
"i.e change its spin the other one insantly becomes the same spin" ~ Louis Cypher
There are 2 problems with this sentence. If you change the spin of one electron it won't change the spin of the other. What happens is they become unentangled when you "copy over" the spin. The other problem is that when 2 electrons are entangled by spin, they don't have the same spin they will have opposite spins.
I just started learning about entanglement, so there's a chance what I've said is wrong, but I'm almost sure it's not.

PS: I hate when people say string theory is philosophy. Even if we have no way to prove it it's still much closer to physics and has only a couple resemblances to philosophy. I bet someone who is very important to or against string theory said it and almost everyone else who says it heard it from someone who heard it from someone who heard it from him. (I wouldn't know really)

17. Dec 23, 2004

### Louis Cypher

I'm talking about photon electron entanglement or photon entanglement not electron entanglement, your referring to the experiment where two ecletrons with opposite spin only became a ceratin spin when viewed, maybe? Look up quantum entanglement in relation to photons, they have allready transfered information using photon entanglement, it is a real technology that has been used in quatum encription to send 'unbreakable' codes, it is quite well accepted so that's what I'm referring to.

String theory is philosophy because:- philosophise def: to postulate an argument for the sake of education or discussion in order to icite thought; an argument wich may have no scientific basis but which searches for truth by logical extension and conjecture etc; string theory no proof whatsoever , therefore what's the difference.

That's why most scientists dismiss it as a flight of fancy untill they see the proof; wait for proof before you pass judgement for now say if and maybe, you probably are trying to make hypothesis based on conjecture yourself and this is great this is what scientists do but there very wary of saying it's proven or even it could be true, if there'd no evidence; fine, you may be right, and theres no harm in philosophising for now, but dont expect the scientific community to take it seriously untill they see proof; they say if its true then it might be that dimesion 6 is the dimension of the bannaneons and seven is ludicrons eight is etc, oh and conveniently cos we cant percieve these dimensions we may never be able to prove it cos there too small as well; oh really! How convenient? Some, String theorists seem to have decided it's allready prooven and are working on it like it really is a theory instead of a hypothesis there are people working on it, but its for a doctorate of philosophy, do you see why they then call it philosophy because my friend it is?! :-)

The first quantum mechanics papers by einstein were philosophy thats how he became a prof, some times people are really defensive of ideas, I'm not saying its nonsense, that would be like saying god doesnt exist or vice a versa I'm just saying where's the proof; till then it's philosophy, I hope that clears that up.

Thanks for replying though, no one else has:-)

Gary

18. Dec 24, 2004

### Louis Cypher

see other posts for clarity thanks

Gary