abge...if one man proves a new concept, it is proof, it he proved it. That 1,000 others said "Nay" is irrelevant....or else we might never have gotten past the concept of a flat earth.

You know what....disagree with me if you want. Just be *damned* sure that you *understand* why you don't believe, that you are *open* to ideas, and not closed. I am encouraging you to not be too smart for yourself. I'm trying to encourage you to explore beyond "accepted" beliefs...because I've seen "accepted beliefs" thrown out over and over and over and over in my short life. Science is *fluid*, my friend, not fixed.

it is high time that you graps that idea. If y ou want to be a scientist, then your job is to explore, to expand upon knowledge and, when necessary, THROW IT OUT because you have BETTER knowledge.

Get it, Abge?

Well, to be clear, I'm an engineer, not a scientist. But, I understand your point and agree with you.

However, where is that one proof? I've yet to see it. We've all explained why those papers from yesterday don't prove your point.

Abge -- I want you to believe it is true *because it has been demonstrated*. How many times do I have to state that?

1. Do you believe in photon teleportation?

if yes, the 2. How did they prove it?

Regarding answer #2...IF they proved it....if they proved that they changed a state....then that it information being communicated. Fuck your "classic" definition of communciation. I don't NEED to know if you are transmitting a 0 or a 1....all I NEED to know is that a state changed.

So...instead of "Was 0....now it is 1..." let's run a logic circuit. "Does A1 <not equal> A2"....then State Change...and thus communciation. if A1 is A reading and a2 is a reading in the next reading, or whatever term you want to use...but Ax is the reading of that same item over time.

Good god....not that difficult a concept. YOU assume that communication MUST equal 0 or 1....which is ridiculous. Because communication can be ANY change of information, whether direct "voltage moved from 0 volt to 5 volt" or indirect "voltage change + or - 5 volts....but it is now 5 volts different"

Expand your mind, man.

If this is so easy, why do 2 mathematicians and a physicist agree with me and disagree with you?

The papers don't prove my point? Really? So HOW do you verify photonic teleportation is you don't measure any change? Explain that....and I'll be done. But...since the verification of teleporation must include acknowledging a change of state, then you must necessarily have noted a change in state...and thus.....<sigh...><again....>....a communication of information.

You bore me.

Go repeat like a good robot your answers to your professor and get your good grade. You will graduate with employable knowledge....but nothing *current*.

Congratulations.

And I am an engineer, too, for the record...and a good engineer **is** a scientist. Engineers in the field, doing development for corporations, explore and expand knowledge....that what the whole "patent" thing is about, you know? You if you think you are an "engineer" but not a scientist....that you are not getting your money's worth.

That isn't to imply that my point is more valid because more people agree with me, but it should make you pause and think why we're disagreeing with you.

**2** whole mathmeticians? And ONE whole physicist disagree with proven science?

Oh my....now I must rethink everyting....

I would guess...on a whim....that you think Al Gore is a valid source of information on the climate, too, correct?

(Just trying to gauge what you view as valid sourced of info...)

No, I don't think Al Gore is a particularly unbiased source of information.

krellin,

I am honestly interested in your opinion on this:

In this paper you sent me, they say this:

"Although the projection postulate in quantum mechanics seems to
bring Alice’s attempts to provide Bob with the state |wi to a halt, it
was realised by Bennett et al.
1
that precisely this projection postulate
enables teleportation of |wi from Alice to Bob. During teleportation
Alice will destroy the quantum state at hand while Bob receives the
quantum state, with neither Alice nor Bob obtaining information
about the state |wi. A key role in the teleportation scheme is played
by an entangled ancillary pair of particles which will be initially
shared by Alice and Bob."


Can you please explain how they communicate when they clearly state neither obtains info about the state?

http://www.qudev.ethz.ch/phys4/studentspresentations/qip/quantumTeleportationExperimentNature

Also, if I may ask, why do you continually insult my professors? Do you have a problem with all academicians or just mine? My advisor has made software that is used worldwide by researches and industry, so he's not even in an ivory tower. Just not sure why you're hatin' on them.

@krellin, Your Fort Knox example is flawed. ALL you can do with entangled particles is measure them. You can NOT change them in some way deliberately and keep them entangled. So you can't say, "If the door opens, we'll change it to a 1." Do that, and it's no longer entangled.
All you can do is measure it, and whatever the result is, that's the result. You have NO control over the outcome on EITHER end, so you can NOT use it to send such information as a door opening (or anything else).

Think of it like this. Somebody takes two boxes and puts a coin in each -- and they're both either heads up or heads down. Then he gives one to you and one to somebody else. You drive hundreds of miles away. You open your box. It's heads up. You now know that his box also has heads up. But if you change your coin to heads down, his coin doesn't change. You've just lost the correlation. So you can't communicate with this.

That's what entanglement is, although there are some additional (very important) properties involving measurement of related, not-quite-orthogonal observables. NONE of these properties, however, allows FTL COMMUNICATION, any more than the coins does. You can insult all you want, but you only demonstrate your lack of interest in really understanding physics. I already cited FROM YOUR OWN LINKS how they did not say what you claimed.

semck

Krellin does raise an interesting point that I don't have an immediate answer to, though.

How do we know these particles are entangled if we change them every time they're measured?

@abge, please clarify. How do we know, theoretically? Or how do we detect, experimentally?
The way we detect it is in correlation. If we measure the same thing in both, we get the same result. If we measure different-but-not-orthogonal things, then we get specific correlations that aren't the same as for unentangled particles.

Yes, yes, you're right.

It's been a while since I've done anything with spin and forgot that the particle keeps its spin until a different direction of spin is measured.

In any case, I agree with you. In krellin's example, you could use entanglement to randomly instantly set off a bomb, but everything was setup classically. There's no fundamental difference between flipping a coin here or flipping a going instantly 100 miles away.

So, I've been keeping up with reading this thread, and I have only a layman's knowledge of QM. Basically, entangled particles act the same, but if you changed one then they would no longer be entangled? So we could observe the same thing from both ends, but would fail to send any information other than that we know both ends observed the same thing? Please let me know if that sounded correct.

That's right Warden.

Yes, I believe this disentanglement is also the key to my thought experiment. It's pretty simple actually. From my point of view, the spins are in state |++>+|-->. I measure S_z, which makes it |--> (and I measure spin down). Then Bob measures, which projects the
|--> state on the y-basis, and it becomes |-->+i|-+> (and Bob measures up). Afterwards, the my spin is in the z eigenstate, and Bob's in the y eigenstate. The system is in a pure state, and the degree of entanglement is zero.

Anyway, let's get back to the really exciting topic: the neutrino's. Is there anyone on this site that can read the paper (http://arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf) and report about it? I tried, but it's way too experimental for me (I'm more of a mathematical physicist). Abge/semck?

Oh, and krellin, please don't get mixed up in a discussion you clearly don't understand.

So, apart from being interesting, as of yet there is nothing 'useful' about QE? Unless we find a way for a change we make on one end to be reflected in the other particle; then we would be able to use FTL communication. As to that paper; I read the Abstract and the first section. It was more than enough for me to realize I don't know enough about my subatomic particles to make heads or tails of it.

@Warden

No, QE is very useful for Quantum Computing, which won't allow for FTL, but will allow for some amazing computational improvements.

@bas

I printed it out; I'll give it a shot.

'So we could observe the same thing from both ends, but would fail to send any information other than that we know both ends observed the same thing?'

i vaguely disagree... we can communication using normal means and find out that both ends observed the same thing. This is great, and once we know that two particles are entangled we can tell that whatever we measure at one end they will get the same result at the other (without asking them) - actually i think it's the opposite at the other end - This is actually great for using in encryption... specifically because we should be able to setup a system where we read the bits and then the information is destroyed, and the other side can do the same, thus giving us a one-use pad of random 0's and 1's, but you're still talking about sending the encrypted information via 'normal' means...

FTL FTW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I am to busy right now to indulge in this debate, but it is probably very interesting.

Expect my return sometime next week.