70 replies to this topic

[Hippie3]

since photons travel at lightspeed
relativity says time has stopped,
therefore nothing can happen,
which would presumable include
changing from a wave to a particle.
it's one reason i asked about neutrinos,
because we used to think neutrinos moved at lightspeed
but research on solar neutrino emissions
eventually revealled that neutrinos were changing 'flavors'
as they travelled from the sun to the earth,
forcing the conclusion that since they were changing
therefore they must be travelling slower than lightspeed
and thus had a mass.
interesting how
the same time-stop argument hasn't been applied to photons...

[BuckarooBanzai]

Relativity has fundamental problems at light speed (in a vacuum) and at absolute zero.

On the one hand, at light speed, a photon is pure energy and no mass. On the other hand, at absolute zero, that same photon is pure mass with no energy. Both these extremes represent infinite amounts. Physics despises infinite (or divide by zero) results. Infinite results cause mathematical provability to totally break down.

There are similar and disturbing infinite results present when you apply Relativity to heat transfer as a wave/particle phenomenon.

The standard argument is that true vacuums don't exist (even in deep space) and that photons propagate much slower through a medium. This is why severe time dilation effects aren't attributed to photons of light that we can observe, moving "slowly" through air.

I think that it is a little bit of a cop out to avoid the infinite result in an equation by saying "those conditions could never exist in nature."

Also, a slight clarification. Relativity doesn't say that time stops when something reaches the speed of light. Time for the object continues to pass as normal, to it. To us, the observer, the perception of time passing is massively dilated to the point that it seems as though the passage of time for the object has ceased.

A really interesting thing is that time dilation has been categorically demonstrated with synchronized chronographs and long hyper sonic flights on spy planes.

The Neutrino flavor/form theories are pretty cool and daring things. Because if a Neutrino had mass, if it had a flavor, it wouldn't be a Neutrino as we've developed the concept. If the flavor's theory proves usable, Neutrino theory will have to be fundamentally revamped. And lots of theoretical sub-atomic particle stuff has links to Neutrino theory.

That's one of the reasons I love Physics so much. There is so little really "known" and what we do "know" is being regularly revised by theorists and experimenters. Our level of precision, at this point, is just astounding and marvelous to behold.

It's very cool to study a discipline that can be turned completely ass over teakettle by a disheveled patent clerk with an idea!!!

I mean, before I threw my thing down, this was originally a thread about celebrating Einstein...

[omnibot]

Buckaroo-

Set up a theoretical example experiment for me whereby you could transmit a message using quantum entanglement.

[BuckarooBanzai]

Theoretical experiment, eh? Cool. They are my favorite...

The following is a pure thought experiment full of assumptions and imaginings. The technology doesn't exist to actually do this (that’s what makes this experiment theoretical). This is *NOT* meant to describe an experiment that could be conducted with existing technology.

Begin by imagining two one meter long glass cylinders that contain a perfect vacuum. Not a hard vacuum, but a perfect vacuum. No free particles what so ever.

Imagine that on the ends of each cylinder is a perfect mirror, mounted horizontal to the other mirror and perpendicular to the tube. If it helps, just imagine a one meter piece of PVC pipe with mirrors glued to either end.

Imagine that in the center of one tube is mounted a detector capable of non-invasively reporting a photon's spin. Mounted in the center of the other tube is a powerful toroidal (circular) electromagnet that can be turned on and off at will.

Imagine producing an entangled pair of photons. Introduce one photon to the detector tube (tube A). The photon should be introduced at a perfect right angle to the mirror. If the vacuum, mirrors and angle of introduction are all perfect, the photon will bounce back and forth between the mirrors (and through the detector) forever.

Imagine introducing the remaining photon into the second glass tube (tube B). Again, if everything is perfect, the photon will bounce back and forth between the mirrors (and through the electromagnet) forever.

Now, when the magnet in tube B is turned on, the photon will have its spin modified by the magnetic field. According to quantum entanglement theory, the photon in tube A will also change spins to match its entangled partner.

Imagine moving the cylinders ten miles apart. Imagine one experimenter (experimenter A) monitoring the detector on tube A. Imagine a second experimenter (experimenter B) operating the on/off switch on the toroidal magnet in tube A.

When experimenter B powers on the electromagnet, the photon in tube B will have its spin modified. Via quantum entanglement, the photon in tube A will instantly have its spin modified to match.

This allows for a binary transmission of information. In a nutshell, every time experimenter B flips his switch, experimenter A can detect it. These are our binary ones, the switch flipped on. If the switch remains unflipped, however, the photon stays in it's known, base. These are our binary zeros.

Morse code could easily used to communicate after this fashion.

[omnibot]

This is going to be a difficult discussion because it is going to come down to what is theoretically impossible and what is practically impossible. It is my understanding, and I believe this is backed up by quantum mechanics, that it is impossible to make a measurement on a quantum scale without disturbing the thing measured. This is a matter of theory, and not a matter of our methods of measurement. Spin is the property of a photon that determines in what direction it will add angular momentum to an electron in the shell of an atom. The ONLY way to determine a photon's spin is to have it collide with an atom.

You cannot modify photon spin with a magnetic field. And even if you could, you couldn't know it because in order to know which direction the spin is in you have to make a measurement, which destroys the photon.

Lastly, entanglement only exists until the first measurement is made. The first measurement made on one of the photons and the first measurement made on the other photon would be linked, but subsequently entanglement is destroyed.

The core reason that one cannot use entanglement to transmit information is that even if one person makes a measurement that effects the other photon, it is impossible to know ahead of time the outcome of the measurement.

Let's say two photons are ejected from an atom and that they are perpendicularly polarized.

If I measure one of the entangled photons to be vertically polarized (it passes through a vertical polarizer) the other photon will necessarily pass through a horizontal polarizer. The original polarization directions of the photons is unknown, and actually irrelevent. Quantum mechanics says that the photons were actually in a superposition of polarized states until the polarization measurement "collapsed" them into one possibility.

I agree with you that in a way it seems that information is being transferred from one photon to the other instantly about the collapse, but it remains impossible to use entanglement to transmit any sort of message faster than the speed of light.

I think that perhaps you are confusing quantum teleportation with the ability to send communications faster than the speed of light. Read over the quantum teleportation section of this Stanford website, http://plato.stanfor...es/qt-entangle/ and let me know what you think.

It is a widely accepted fact by the physics community that you can't use entanglement to send messages faster than the speed of light. If you can, find me a paper by a physicist or a reputable website that supports theoretical communication at faster than light speed through quantum entanglement.

[omnibot]

Ok here's a crazy thought I just had about how quantum entanglement might appear to involve information moving at faster than the speed of light when in fact it isn't. I'm sure you're aware of the many worlds theory. Imagine that when a measurement is made on two "entangled particles" That measurement is actually happening in many many many different universes of possibility. However, any universe in which an inconsistent measurement is made immediately collapses. The only one that continues to exist is the one in which a consistent measurement (for example of perpendicularly polarized photons) is made. It's not that information is transmitted between the two photons, but that every "non-entangled" possibility collapses.

That quite possibly made no sense at all. I'll let you be the one to tell me.

[BuckarooBanzai]

Good post, man. You make me think hard and scramble to justify and I genuinely enjoy that. I doubt that either of us will convince the other of anything, but the exchange itself is still quite marvelous to behold and participate in. Thanks for that.

It is a total tangent to this discussion, but I continue to be amazed by the number of people who fancy both psychedelics and theoretical physics. It seems, to me, as though the two are entwined on a very deep and fundamental level.

Well, not to try and justify, but you did ask for a theoretical experiment. That lets me make up any kind of equipment I can imagine, realistic or not. Thus, I “invent” a machine that can non-intrusively measure a photon’s physical characteristics (something which is absolutely in contradiction with quantum theory). Also invented was the “magnet” that could non-intrusively modify a photon’s spin and the “perfect” mirrors to bounce them between. All of these things are physical impossibilities with existing technology. Again, though, you asked for a theoretical experiment…

Once we measured and probed the microscopic world by “smashing atoms.” Then we improved precision and began using individual protons and neutrons as probes. Then we improved precision again and started using electrons. 20 years from now, it doesn’t seem at all improbable that our precision will have improved to the point we can use things far smaller than photons as probes/detectors.

If the particle that measured the photon’s characteristics was a few orders of magnitude smaller than the photon, Heisenberg begins to mean less and less. The use of a Plank length particle (say, a wound string) would have a negligible effect on the photon, just as measuring molecules with photons has negligible effect on them. What effect was present could be corrected for, if the probing particle was very small (compared to the particle being measured).

Gisin’s experiment demonstrated, quite clearly, that current technology could only play “catch up” to quantum entanglement. The evidence of one photon effecting the other could only be realized much later, when the data was tabulated and analyzed.

The problem, for me, is that much of the “detail work” of quantum theory has yet to be mathematically reconciled with general relativity. Yet GR and QT have both been experimentally proven (time and again) to be self-consistent, if applied in a size specific way. GR makes perfect sense when considering cosmology and the macroscopic world. QT makes perfect sense when considering sub-atomic interactions and the microscopic world. Both work in their apropos arena, but both collapse when moved into the other’s arena.

Classical mechanics work fantastically when predicting interactions between pool balls, planets and galaxies. Quantum mechanics work fantastically when predicting interactions between atomic (and sub-atomic) particles. But, you cannot directly derive quantum mechanics from general mechanics (or vice versa). There is an unavoidable breakdown because the mathematics are simply incompatible.

To me, this indicates that both theories need fundamental revision (or replacement). I DESPISE the cosmological constant, despite it’s infinitesimal value. Any application of a correction factor, to me, implies not a fundamental theory but rather a useful approximation. A fundamental theory should (to me) be universally applicable, regardless of scale or the amount of energy involved. Any lack of universal applicability (to me) indicates not a fundamental theory, but a fundamentally flawed approximation.

That’s a long way around to it, but my point is this: mixing quantum theory and relativity theory isn’t useful at our current level of understanding. I say this because, on a fundamental level, I find these theories to be incompatible because they predict very different things at the extreme ends of the scale. Until the mathematics is worked out (until one theory is clearly derivable from the other without correction factors), I reject any argument which makes use of them both, because I find them to be fundamentally incompatible. That’s a personal opinion, but it is one shared by others. I am NOT in the majority, but I’m also not the only one out there who believes both quantum and relativity theories need fundamental revision (because they are not mutually derivable).

When you discuss classical considerations like polarization in relation to quantum considerations like superposition, you are (in my admittedly addled mind) mixing incompatible theories. When you further introduce concepts like probability wave collapse and “many worlds,” the waters become even more muddied.

That Stanford link, by the way, is fantastic. Very plain language that even the non-geeks can dig on. Thanks for that. It’s going into my collection…

That said, quantum teleportation and quantum entanglement are subsets of the same concept: information of some kind instantaneously transmitted (or already known) that allows an entangled pair to recreate their partner’s state, even after an unknowable modification by an experimentor occurs. Bob could not know how to transform his photon’s state of U* into U (Alice’s modified state) without some information as to what change had resulted in U*.

The Stanford link says specifically, “Alice and Bob have managed to use their shared entangled state as a quantum communication channel to destroy the state u of a photon in Alice's part of the universe.” Call it teleportation or entanglement or pink elephants, information is still being exchanged between Bob and Alice such that one photon can “know” the other’s state and, subsequently, re-create (or approximate) it. If Bob and Alice are moving away from each other at the speed of light, this result invalidates general relativity as any communication whatsoever between their particles (even an encoded probability limited by an interaction and initial state) is impossible.

Even if only one bit of information is exchanged (and entanglement is destroyed by this exchange), it doesn’t seem beyond the realm of possibility that we could exploit that exchange to transfer information. Regardless of the proposed mechanism, information is being exchanged by the photons. Even if that exchange is nothing more than a limitation of probable results that each contained from birth, that limitation of probable outcome is somehow transferred between them.

As to “many worlds” (a theory I truly love, by the way), how do the “non-entangled” possibilities know that they should collapse and become irrelevant? Somehow, information as to relevance and irrelevance is communicated to all the possible outcomes, such that only one world continues to exist after we collapse the probability wave with a measurement. In “many worlds” not only is that communication instantaneous, it is made to an infinite number of possible outcomes simultaneously. Even if this communication is nothing more than a limitation of possible outcome based on initial state and encoding, that limitation is somehow communicated between all possible outcomes such that they agree on which world they exist within (after measurement). In many worlds, not only is entanglement communicated instantaneously, it is communicated instantaneously to an infinite number of listeners.

We are arguing the same point, we just have diametrically opposed opinions as to the mechanism involved.

Your second post made perfect sense, by the way. It just makes a different kind of sense to you than it does to me. To you, no information is exchanged, possible outcome is simply limited by probability collapse and an initially encoded state. To me, information exchange is directly implied by the limitation of collapse itself. To you, the collapse of probability is based on the intrinsic nature of the particle pair. To me, the collapse of probability is based on information exchanged as to what probabilities work and which don’t, when one probability is collapsed by a measurement. These are not mutually exclusive considerations.

Most interestingly (to me) is that neither of these arguments is automatically “right” or “wrong.” Each is applicable and potentially right, based on circumstance. Each makes perfect sense, in it’s own bailiwick. Somewhere, in between these theories, lies “truth” and the resultant universal applicability that “truth” implies.

Once a universally applicable TOE is posited and proven, discussions like this will become irrelevant and learning will become rote regurgitation. Experimentation will become a simple mechanical exercise to prove what we already know. I don’t remember who said it, but I agree with him. The universally applicable and proven TOE will signal the end of the “human experiment.”

Might I be so bold as to ask your feelings on chaos theory and deterministic manifolds?

I AM trying to change the subject because I don’t think we’ll get very far with this exchange if we can’t get away from fundamental disagreement and find some common ground. I suspect that betwixt the two of us we agree on far more points than we disagree and I am very interested in continuing this exchange. Also, if we can find some commonalities, we will be much more likely to actually convince one another of something.

I am far more than willing to revamp my opinions, based on new considerations.

[omnibot]

I must say that I don't have very strong feelings about chaos theory or deterministic manifolds.

I view physics as an analogy. Physics is the analogy of numbers. We have realized that we can draw a very accurate analogy between mathamatics and the world around us. Yet like any analogy, this one becomes weak when drawn out too far. We have specific analogies for specific areas of reality (ie relativity and qm). Each one, however, becomes inaccurate when we attempt to apply it to a foreign scenerio.

It may always be possible to come up with a more accurate analogy, yet I strongly take exception to the possibility of a theory of everything. We have not discovered a SINGLE equation that perfectly describes a physical phenomenon. We get closer and closer, but we never get the cigar. Not only that, but the equations we come up with to describe deeper and deeper truths about existence become gradually more complex (though not less elegant) as the the truths get deeper. I tend to think that only an infinitely complex equation, an impossibility, would be able to describe existence perfectly. Everything else is an approximation.

Chaos theory is a good example of this. Chaos theory is so named because a small inaccuracy in our beginning measurement of something may lead to large, unpredictable innacuracy later on. It's not that the underlying reality of the thing is chaotic, however. It's simply that the best we can do is never perfect.

Well, now that I think about it, that's not quite true. Even quantum uncertainties (inherent) can lead to big differences in the final state of things. You seem to have some thoughts on the subject though, so pour them forth by all means.

I still hold that it is fundamentally impossible to use entanglement to send a message, but I agree that we will probably not get very far by continuing our discussion about it. We do seem to have some fundamental differences in our interpretations. My challenge from my last post, however, still stands. :)

"If you can, find me a paper by a physicist or a reputable website that supports theoretical communication at faster than light speed through quantum entanglement."



"A fundamental theory should (to me) be universally applicable, regardless of scale or the amount of energy involved."

This is exactly what I think is impossible. It is fundamentally impossible to create a perfect analogy, whether in physics or everyday language. The only perfect analogy is the thing itself.

"Most interestingly (to me) is that neither of these arguments is automatically “right” or “wrong.” Each is applicable and potentially right, based on circumstance. Each makes perfect sense, in it’s own bailiwick. Somewhere, in between these theories, lies “truth” and the resultant universal applicability that “truth” implies."

Interesting and valid point. Both ways of understanding are analogies. And yet, my friend, I must sadly inform you that my analogy is much better than your own. ;)

Going back to chaos theory, I just remember that there is one aspect of chaos theory that I find very interesting. That is in the self-similar patterns that arise in a "chaotic" system. Fractals... Even more fascinating for me is that all chaotic systems are self similar at the same scale. I forget the exact proportion, but I think it's 4 something. Even more interesting is the possibility that information is encoded in DNA in a fractal like way. There is not enough information in DNA to determine the exact location of every cell or every blood vessel in the body. The only information needed is an "equation" and a "repeat" signal. Blood vessels are structured in this way I believe. They never repeat themselves and yet their strucure is repeatedly self similar. Much less information is needed that way.

So I guess I do have feelings about chaos theory. Heh.

[BuckarooBanzai]

Good post, man. Ya makes me think, brother…

Unfortunately, though a “simple” TOE does appeal to me, I tend to suspect that the actual equations involved would be like Stephen Wright’s life sized map (the scale in the corner says 1 mile equals 1 mile). Basically, any such a complete analogy would be roughly the same size as the universe it was attempting to describe – if not a tad larger. Not saying I wouldn’t enjoy trying to work such an equation…

But at the same time, a simple TOE is an awfully nice dream (utopian and perfectionist though that dream may be, it’s still a nice one…to me).

I STRONGLY believe that there is, however, a very distinct (and as yet undiscovered) “Quantum manifold.” But, I’m a self admitted manifold whore. ESPECIALLY deterministic manifolds. If it can’t make accurate predictions, after all…

I find mathematics far more elegant and beautiful than philosophy. I just don’t loose too much sleep over my “precious manifolds” being updated and/or replaced (none of them are my work, after all, so that’s an easy position for me to take).

“I must sadly inform you that my analogy is much better than your own.”

No reason to be sad and no argument could I make. Your analogy IS far more applicable than mine. Chaos theory has far more holes than workable proofs. The same is absolutely true of string theory (more true, in fact). Even imagining the algorithms that would define string proofs has thus far proven utterly impossible. In fact, the work that has been done suggests that the theory is either totally off the mark or totally incompatible with mathematics as we understand mathematics. I would slightly change your quote, however, to:

“my analogy is much more complete and much better understood - AND can actually make predictions.”

Words like better just bug me, even though I agree with you completely. And reminding me that “my” analogies lack provability stings a lot more!

For whatever reason, I just lean a little differently than you do. I find it most refreshing to discuss this with someone who also realizes that what we are talking about are approximations (analogies as you state most eloquently). There are far too many ivory tower types out there already. I’m glad neither of us is a “purist.”

If I may be so bold, I don’t think that either of us is looking for answers. I know I’m not looking for answers; I’m looking for better questions. I find answers to generally be pedantic and limiting, highly indicative that the interesting work of discovery is already over. If I have put undesired words in your mouth, please speak up.

Self similarity is, to me, the most interesting thing about fractal/chaos theory. I CRAVE a mathematical system that could express that similarity without insisting on repetition. The fact that the Julia set could be non-repeating yet still maintain self similarity is such an eloquent and beautiful thing, to me.

Blood vessels, tree roots/branches, coast lines – all are good examples of self similar fractal/chaotic systems. We can’t yet actually model these systems (or predict them) accurately, but our eyes can see things our math will never be able to convey. That doesn’t mean I don’t dig the hell out of the work being done to find those models, though. Finally truly grasping the Julia set was what gave me the toolkit to an understanding (admittedly, a VERY skeletal understanding) of Diffie-Hellman.

If I could advance your DNA analogy with my own considerations, I strongly believe that the information in DNA is not only “chaotic” via programs/repeats but highly compressed/encrypted as well. Both these approaches allow for far more information to be contained in those magnificent double helixes. With encryption, compression and chaos theory as backdrops, expressing the subtleties of physiological form with a “simple” 4 letter alphabet (and an awfully short “book”) becomes not only possible but highly probable.

One way or the other, this is a damned interesting time to be following theoretical physics.

And I capitulate on the “prove you can use quantum entanglement to communicate a message” challenge.

[Mychotic]

Wow... I consider myself to be an intelligent and (at least getting to be) educated individual, but I think I've just gone cross-eyed. :special:

[BuckarooBanzai]

This is what happens when math/physics geeks start blathering at each other. Try to imagine being in my wife's shoes when I "get" something at 3AM and insist on discussing it with her! She has SO mastered the "smile and nod and repeat back what I'm hearing in the form of a question..."

By the way, if you got enough of it to twist your head at all, you are doing far better than most!