A Model For Eliminating / Confirming Time Dialation

Fallen Angel, the ticks on clock by entangled particles had the effect of making another idea pop up in my head. I know Special Relativity says it can't be done,
but I want to know why this won't work. Use entangled particles to transmit a
message by a Morris Code like method, instanteously. After first separating two
groups of entangled particles (photons or whatever works best), a person at either
group can send a message by destroying entangled particles in a time-like fashion,
you know, long-short-short-long spacing like used by the old telegraphs. Surely
someone has thought of this idea before, so why would it not work?

 

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2Inquisitive,

Excellent idea. The fact is they probably haven't thought of that. I had suggest another means of communicating in another thread and that would be to send a string of entangled particles and then selectively alter positions in the string to form a binary message.

Seems to me either approach overcomes the "No Communication" arguement.

 

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No, this just means you both have not understood what entanglement is all about. You cannot transmit any information using entanglement. To understand what it really is about, you'll need to take advanced courses. All I can say is that the entanglement effect is "local" (it happens only for one observer and the other notices nothing about it).

 

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Perhaps you need to brush up on quantum entanglement, Crisp. Information has been
sent by quantum entanglement many times, although so far mostly as encryption keys.
Here is a link to an papre on a bank transfer using Quantum Cryptography. A cut & paste first:
"Today, the Bank Austria Creditanstalt has, on behalf of the City of Vienna, performed the
World’s first bank transfer encoded via quantum cryptography.
This novel technology was demonstrated by the group of Professor Anton Zeilinger, Vienna
University in collaboration with the group Quantum Technologies (Information Technologies
Division) of Seibersdorf research. The bank transfer was initiated by Vienna’s Mayor Dr.
Michael Häupl, and executed by the Director of the Bank Austria Creditanstalt, Dr. Erich
Hampel. The information was sent via a glass fiber cable, laid by the company Wien Kanal
Abwassertechnologien from the Vienna City Hall to the Bank Austria Creditanstalt branch
office “Schottengasse”."
http://www.quantenkryptographie.at/Quantum Cryptography 21 April 04.pdf

A more detailed paper is from Los Alamos National Labs, U.S. Dept. of Energy. A cut
and paste:
In the Los Alamos implementation of Ekert’s cryptography protocol,
researchers used a pair of special optical crystals placed in a beam of
ultraviolet light from a laser. Occasionally an ultraviolet photon from the
laser is converted into two infrared photons. These daughter photons
share the almost magical correlations of entanglement.
The polarization-entangled photons are then transmitted to the communicating
parties — historically called “Alice” and “Bob” by
cryptographers — to create a random string of 0’s and 1’s known only to
them. This string of numbers becomes the quantum cryptographic key.
Because the photons cannot be intercepted without tipping off Alice and
Bob, the key is secure, as is any data subsequently encrypted with it."

"Therefore, to access longer distances,
researchers here developed free-space quantum cryptography, which
allows codes to be sent through the air.
Recently Hughes’ group demonstrated free-space code transmissions
over a mile, with the eventual goal of earth-to-satellite communication.
This free-space transmission set a world record."
http://www.lanl.gov/worldview/news/dateline/Dateline1100.pdf

 

Wow, this is fask-i-natin' !

 

Quantum encryption is not the same as transferring information by way of quantum entanglement. Although the entangled state is transmitted 'non locally' one cannot 'decode' the encryption without information passed at the speed of light or less. As I understand it, this essentially applies towards any proposed method of transferring information via entangled states. The state could not be used as a simultaneous 'clock tick' because the state is not known until it is measured and then it is set and if you were to change the state the measurement could not be properly made until information had passed at the speed of light from one clock to the other.

http://curious.astro.cornell.edu/question.php?number=612
http://en.wikipedia.org/wiki/EPR_paradox


~Raithere

 

More is being learned about quantum entanglement. Entangled photons can now be
time-correlated, spin-correlated or frequency-correlated. At least two of the states
can be combined. New research on plasmon-assisted transmissions of entangled photons seem to make it possible to determine the spin (polarization) of entangled
photons without destroying them. It involves passing entangled photons through a
metal plate with sub-wavelength sized holes in it. The photon will change into a plasmon going through the hole and reemerge as a photon on the other side without
lossing its entangled state. It is thought the spin may be determined this way without
destroying the photon. That would not be necessary in my example above, only time-
collelated photons would be necessary and the timing between events (destruction)
could be used for a code, like a Morris code. Of course, the entangled photons would
have to be manufactered and then separated by a distance before the message could
be sent and the separation could not happen FTL, but the actual code and message
could. Entangled photons would have to be created, stored at two locations, and as
the photons are destroyed one at a time in a timed sequence at the sending location,
a detector in the receiving location would record the timed sequence, the Morris code.
Here is a link to a site where you can download the pdf paper Entanglement and Surface Plasmons. I couldn't get a direct link to the paper itself.
http://www.molphys.leidenuniv.nl/qo/index.html

Here is a link to a very good paper describing the various types of entanglement and
how frequency-entangled photons can be created at specific frequencies.

"A method for generating entangled photons with controllable frequency correlation via spontaneous parametric
down-conversion ~SPDC! is presented. The method entails initiating counterpropagating SPDC in a
single-mode nonlinear waveguide by pumping with a pulsed beam perpendicular to the waveguide. The
method offers several advantages over other schemes, including the ability to generate frequency-correlated
photon pairs regardless of the dispersion characteristics of the system."
http://people.bu.edu/teich/pdfs/PRA-67-053810-2003.pdf

 

the reason i think you could use entanglement as a "clock tick" is because what you are doing by measuring one quantum particle is disturbing its quantum state. This in turn will disturb the quantum state of a particle in another clock. sure, no information has passed, but you still notice the "disturb" event, and that is all that is required for a clock.

as for information, if the rocket ship originates from earth and you agree on a code, then anything after that, instantenous commo, because you yourself in the ship is/are? the slower than lightspeed information exchange.

 

yeah, i should refresh before posting

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I know I don't need to tell you to correct me if I am wrong.

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However, your typiical comment suggesting advanced course seems a bit out of place when one looks at the overall picture and the status as currently being presented by those actually working in the field.

What I am saying is that it take more than innuendo about our education to show the failure you claim.

1 - There have been several recent breakthroughs. A number of different groups have shown how they can selectively set entanglement. That is establish a spin-up, spin-down or super position correlation, not just random entangled pairs.

2 - They have also shown how to generate multiple or groups of entangled particles. So that one could set an array of say 10 entangled pairs, 10 entangled sets of 4, 10 sets of 6, 10 sets of 8, etc.

Other than mere binary coding actual letters could be indicated. i.e.: 2 = A, 4 = B, 6 = C, 8 = D, etc. By Bob disrupting the entanglement selectively he could therefore pass along a coded word to Alice.

Now I know you disagree with information transfer but that I am afraid is nothing more than a bias; which seems to be rapidly falling behind the times.

 

Judging by the rest of your answer, I can only say that you have only the "general" picture of quantum cryptography and entanglement, and thus also the mistakes that come with that picture.

Fine. You cannot transfer information using quantum entanglement alone. You can use entanglement as a protection for cryptography, but then the information is transfered at speeds smaller than the speed of light.

But hey, you are the expert so it seems....

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Certainly no expert and have never claimed to be but I'll note your post failed to address the issue I raised about creating variable sets of entangled pairs and selectively disrupting the entanglement to transfer alphabetical letters.

That is information and no 'c' or subluminal carrier is required.

Lets try to address this issue and not make this a pissing match.

 

Look Mac, I am not going to debate on quantum mechanics with you. I know that you know hardly anything about it (and this is really really really a mathematical theory) so there is absolutely no point in trying to explain you what goes on quantum mechanically. I already gave you the explanation in "words" (i DID address the issue earlier): you cannot use entanglement to carry information "instantly" as was suggested by 2inquisitive at the beginning of this thread.

You want to know why ? Learn quantum mechanics, there is no "good" way of putting measurement procedures into words (unless you know what is meant by phrases like measurement reduces the wavefunction to an eigenstate of the hermitian observable that you are measuring).

 

I am very well aware of what happens in quantum cryptography. Note that the entanglement is added as a security measure (to detect eavesdropping). Note how the information is transferred at speeds smaller than the speed of light.

This is in huge contrast with your statement of a few posts earlier, where you suggested that entanglement could be used to transfer morse code instantly.

 

Crisp, I suggested you brush up on quantum entanglement because of your statement
that the entanglement effect was 'local'. The very essence of quantum entanglement
is that it is non-local. Quantum entanglement is not compatible with relativity's time-
lines. I thought all physicists knew that. Measuring the properties of one photon of
a pair of entangled photons causes an 'instantanous' event in the other photon. With
relativity's timelines, the reaction happens before the action that caused it always
in one frame of reference. It is a violation of causality, doing something 'now' causes
something to happen in the 'past' using relativity's frames of reference. According to
relativity, there can be no simultanous time between two frames of reference separated by a distance, but quantum entanglement proves this wrong, unless you
are willing to accept that you can cause events to happen in the past. Much more
logical to admit relativity's frames of reference are wrong and there can be an absolute
time. Efforts to reconcile QM and relativity have produced the view that, well no
information can be exchanged by entanglement to eliminate any time paradoxes that
would arise if relativity is retained. I believe it is only a question of time before information IS exchanged instantly by quantum entanglement. They are very close
to being able to do it now. This has been a heated topic of debate between supporters
of relativity and supporters of Quantum Mechanics for years. I side with the supporters
of QM. Bet that is a surprise to you, huh?

 

... but only for the local observer! That is what I meant. If you measure something an entangled photon pair, where one photon is here on earth and the other is on alpha centauri, then you know what state the other photon is in, but not the observer on alpha centauri. He knows nothing until you transmit your outcome to him (using classical communication), or if he performs the measurement himself -- which does not guarantee him finding the same result!

That is what I meant by "local", but I admit that it was a very bad choice of words, given the non-local nature of quantum mechanics

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.

I disagree with your statement that entanglement is in disagreement with any concept of relativity. Both have been reconciled without any problem.

Bye!

Crisp

 

Crisp is right I know very little about QM technically since it is mostly mathematical but I am familiar with the wave concepts involved but on the whole I am very much on your side of the argument and I find the claim that such communication cannot occur based on "because I say so" or "Because Relativity says so", very much in contrast to the general belief of those actually working on such QM functions.

Relativists simply will not flex, they must be buried before they stop wiggling.

 

Crisp, I think all of us mentioned the set up as both parties starting off in the same place, and then departing. Thus, the quantum entangled particles originate from the same source, so, they themselves can only move slower than light. That way we can say that the information was already contained in the particles, and by measuring them (and thus causing an effect in the other entangled one), we just pull out the information that already traveled to us at less than the speed of light. That's my understanding of it being less than c. and i see what you're saying about having to actually measure the particle. my understanding is that by making a measurement on one of the entangled particles, the other one is affected in some way that can generate a measurement indication without us having to initiate it. is this correct?

 

If you pre-selected (coded) the particles, what you say would be true about transfer of information a sub-c velocity. But what of the case where such particles are all set to i.e. - an up spin and then selectively destroy the entanglement triggering an output which can represent a coded message?

 

even then, you still have to seperate them at sub-c velocity yes? unless there is a way to generate entanglement without the particles interacting with each by conventional means. but i thought this was impossible? (generating entanglement without exchange info at sub-c speeds?)