Quantum Entanglement, Compact Dimensions Explain Entanglement?

When I was an undergraduate physics major I read about a series of experiments conducted by Alain Aspect. At the time, I was fascinated by quantum entanglement. As time passed, I lost interest in physics, but have recently begun reading again. I'd really appreciate it if someone could correct my understanding of the following information.

If I understand correctly, a result of quantum entanglement is that sub-atomic particles to communicate even when they are far removed from one another. The strangest thing about these particles is that the communication between them is instantaneous. When they are far apart, they still communicate as if they were right next to each other. Alain Aspect's experiments showed that the "information" passed from one particle to another at faster than the speed of light, which seems to violate the cosmic speed limit.

After reading about string theory, a solution occurred to me. My understanding of the the theory is that our universe is definitely more than four dimensional. The reason that we don't perceive the extra dimensions is that from our point of view anything other than height, width, length, and duration are "compact dimensions". These "compact dimensions' appear to us to be almost infinitely small.

Is it possible that from the point of view of the sub atomic particles that are experiencing quantum entanglement height, width, length, and duration are "compact dimensions". From their perspective, could they remain right next to each other because differences in height, width, length, and duration are negligible to these sub atomic particles.

Please let me know if the idea is painfully obvious or patently absurd.

Thanks

Harry Poter is infinity big and he can do magic on infinity small scale, so for him it's don't seems like he somthing doing faster than light, but for us it seems.

No, that doesn't work. You are assuming the existence of hidden variables, a way of accounting for the properties of entanglement in a way which we cannot measure but which 'the universe knows'. The Bell experiments show this isn't true,

They are explained in the final section here.

Besides, that's not how compact dimensions work. They are not linked to one another like that, so that all points in space-time we see are connected right next to one another in these extra dimensions. The compact dimensions at point A are seperate from those in point B.

Thank you for the clarification. I've been trying to understand compact dimensions using analogies to two dimensional space.

From the perspective of a being trapped on a two dimensional plane, wouldn't the third dimension at any point on the plane be perceived as a "compact dimension"? I assume the analogy breaks down with a greater number of dimensions, but I don't understand why.

Any help you could offer would be appreciated.

If you put the first part of the lecture,you will be appreciated more than gkrajca did:)

A compact dimension is like the surface of the earth (ok, thats 2 dimensions...) If you walk in the same direction (as perceived by you) you'll eventually get back to where you started. Extended dimensions don't have this property - you'll go on forever and never get back to where you started.

Consider the surface of the earth example. We are pretty much confined to the 2 dimensional surface of the earth. If we could move (very far and learn to breathe nothing!) in the "up" direction we could move in all 3 dimensions. Note that the 2 dimensions we move about in are compact and the one we can't move in is extended.

Thanks Prometheus for clarification of the definitions of compact and extended dimensions. Is it possible that the theoretical dimensions postulated by super string theory appear compacted because of limitations in our perception or mathematical models?

To return to the analogy, imagine that a "flatlander" (a two-dimensional being) developed mathematical models to describe how a third dimension might intersect with his universe. From the flatlander's point of view, would depth be perceived as a point (compact dimension) or a line (extended dimension)?

Likewise, why does a physicist living in four dimensional space-time prefer six dimensional Calabi Yau spaces (compact dimensions) to additional extended dimensions?


George

Hi gkrajca, AlphaNumeric, Atheist, prometheus, DavidD et al,

Compact an extended dimensions are one way to "understand" entanglement. Recently there has been an experimental paper regarding quantum entanglement of photons at great separations. Look at this News item...
World's Largest Quantum Bell Test Spans Three Swiss Towns
... There is a scientific paper associated with this experiment at the arXiv repository...
Space-like Separation in a Bell Test assuming Gravitationally Induced Collapses
What this appears to be saying is entanglement is associated with "de Broglie Matter Waves" though the paper is very "obtuse". Clearly they know what they are talking about but want to communicate as little as possible to the general community at large. Semaphore is possible at superluminal speeds. The interference fringing inside of an interferometer 18 Km long is used to check the ends of the experiment. the fringe is changed in one end by tilting the mirror and this "influence" takes only 7.1 microseconds to communicate and "switch" a corresponding mechanical detector at the other end. Calculation shows that even this mechanical setup "flips" in a shorter time interval than light would take to signal the event at the other end 18 Kms away (60 microseconds) producing a "Bell Telephone" like situation. What should be noted is individual photon pairs are not used to trigger this event it is the nett result of a detected fringe that signals the event.

I have attempted to explain it in the page below on the PhysOrg News page (linked above). To do this I "botched" a couple of links there but the link is to a paper of mine I wrote nine and a half years ago. The original SETI site still hosts this paper. It is essentially the same problem, just that we now have an experimental proof. All the "mumbo jumbo" about "gravitational quantum events and Penrose-Diosi Hypothesis" causing switching is really about de Broglie Matter Waves and cavity interference (phase accumulation). This is what Richard Feynman was speaking about when he formulated his Quantum Electrodynamics many years ago. It is related to "gravity" in a round about way but it really relates to quantum interference due to "matter waves"...

I have put my "spin" on this for clarity sake and it may help with people understanding what this is all about...

I have corrected the links here and I should say that this second experiment is not in any way meant to test the non-locality of the phenomenon but it could be made to with a few small modifications.

The interpretation of entanglement to me is related to the idea of quantum resonances in two separate localities. Once again the "mumbo jumbo" and language to describe "squeezed states" really means "tuning of a resonant" signal. The amount of Uncertainty is "squeezed" to almost zero... it is a resonance differing only in spatial phase. The emission and absorption of a photon emitted from a common entangled source affects the other photon through a loss of coherence ... instantly. The polarization state is also affected but what is important to the signaling of information is the effect on interference and this is a phase related phenomenon. Quantum Physics is usually written to deemphasize this "source coherence" through phase but Feynman's QED describes this quite adequately and should be seen in the light of his earlier theory of Wheeler-Feynman Absorber Theory where advanced and retarded waves are used to describe the dynamic state of the "co-located" property through "entanglement". If you think about it at the source the two photons are linked through the common Null Geodesic to each other. The source and the sinks are "instantly" communicating with the sinks at their respective endpoints. The reading of one of these states will cause a de-coherence of the other photon. This de-coherence can be measured as a "bulk property" of many co-moving photons on the wavefront. The interference fringes in both arms of this "interferometer" communicate with the cavity fringes instantly since it only takes one photon at a time to create these fringes (the interferences are not related to intensity or to mutual interaction between photons). The collapse of one of the entangled pair of photons affects its orthogonal "brother's" fringes instantly no mater where it is even 18 Kms away. So I can't "predict" the results of individual photons at either end but I can say that the loss or disturbance of these interference fringes can be correlated with an event at one end of the "interferometer" or the other. One certain event is surely the moving of a shutter or a mirror... No argument about that. This occurs with a 7.1 micosecond onset to "move" a mechanical system when we know that a "signal" takes around 60 microseconds "electronically" to communicate at the speed of light. The "interferences" are quasi-stationary for a fixed interferometer and photons move along paths of least time so there is absolutely no time for photons to communicate "end to end" (... nor do they... we know single photons "know" all about the cavity through the de Broglie Matter Waves due to the position of the matter in the cavity, mirrors, lenses, cavity dimensions such as slits and holes etc.)... the answer is to be found elsewhere... Phase accumulation and cavity resonance and tuning (... back to the "good old days"... he he he!). This also echoes of Richard Feynman's old friend and associate, Carver Mead, and his theories which have gone largely ignored (see "Collective Electrodynamics").

Photons are the most extreme case of "length contraction" and "time dilation" such that both entangled photons (and their source) are on the one null geodesic (which is zero length and zero time relative to each other) are in the same spacetime place and at the same "null" time as the source that is generating them. Other observers not co-moving with photons can see these are separated events ... separated by space-like or time-like worldlines. We see this all the time with standard transmission line theory (and practice) where the source and the sinks (load) are tuned to emit and to sink the energy of the emitted photons (a mismatch at any end affects the overall load through "interferences"). Event by event the photons are "transacted" and mismatch will reflect the photon back to the source affecting the load. This same effect is seen in the Delayed Choice Quantum Eraser Experiment where each entangled photon can "retrospectively affect" it's dual earlier in history since once again the two entangled photons are linked across "our" time and space by a segment of zero length in time and space... the same point simultaneously until after the quantum event has been decided. At that point in time the event is described with two (or three for entangled photons) separate locations.

This is also a verification of Cramer's Transactional Quantum Interpretation. Any radio tech can tell you this and this demystifies quantum entanglement "immediately". Is this "higher dimensions"?... Possibly... because the photon is "bilocated in space and time" in a special way and is not interfered with while in transit... It is one form of long distance quantum tunneling or teleportation (for photons). The difference is simply the distinction between the evanescent (near) field and the far field which leads to separation of events in their interpretation.

Cheers

This post has been edited by Good Elf on Jun 20 2008, 05:12 AM