# A simple string theory model of EPR entanglement

1. Jan 15, 2004

### yanniru

I would like your comments on whether a model of EPR entanglement based on superstring theory makes any sense.

Let's suppose we are concerned with understanding the entanglement of an electron/positron particle pair created at a point in an EPR experiment. The particles fly off in opposite directions but their properties in some sense remain correlated. They are said to be entangled and it is as if they behave like one particle.

Now in string theory it takes 10 spacetime dimensions (plue or minue one) to create fermions- in this case an electron/positron pair. It is claimed that 6 of the space dimensions must compactify for the fermions to exist in 3-d space.

My thought is that the particles of the particle pair remain connected by the 6 compactified dimensions as they separate in 3-d space. The compactified dimensions form roughly a Planck scale diameter thread going from one particle to the other. [After one or the other particle interacts with the environment or the experimentor, the thread precipitates into 3-d space, probably as axions or some other particle of minute mass. But that is a digression.]

I have never seen such a simple model for understanding entanglement in the literature and therefore presume that there is some reason why such a model is just plain silly. Could some explain what that reason is?

2. Jan 17, 2004

### jeff

So what you're really saying is that you don't understand entanglement, right?

3. Jan 18, 2004

### yanniru

No. What I am saying is that my understanding of entanglement in the EPR experiments is so straightforward that I am suprised it is not yet in the literature. So since no one on this forum seems to know of its being in the literature or can refute the model, I had better publish it right away before one of you steal the concept.

4. Aug 6, 2004

### gendou

i, too, had this idea. it seems to be an obvious and beautiful result of the string theory. the fact that we have now proven that entanglement is real conclusively (June 17 issue of Nature: Rainer Blatt) means that we now have some actual evidence to support the string theory! i share the same shock that this has not been investigated or even talked about. i did some pretty extensive google-ing and all i came up with was this thread!

5. Aug 6, 2004

### yanniru

Are you capable of researching this idea? I am not.

6. Aug 6, 2004

### sol2

Hi Richard,

I have a little story for you, over, in the other thread.

Do not let Jeff deter you in your questions. He has a habit of chasing away intelligent people, and hopefully, one day, someone else might come back here too.

regards

7. Jan 7, 2009

### alemsalem

i also thought about this i think, i know about entanglement and string theory but i haven't really studied them, but i was thinking of entanglement and thought that the two particles might be connected through the other space dimensions in string theory, is this what you meant

8. Jan 7, 2009

### humanino

I'm sorry if this is going to be trivial, I'd appreciate if you can clarify this for me.

In special relativity, we say that two events are separated by a time-like interval if it can be connected by a massive object : one has "enough time" to go through the "space distance", so $s^2=\int_\text{space min} (dt)^2-\left[(dx)^2+(dy)^2+(dz)^2\right]>0$. On the contrary the interval will be space-like if you don't have enough time : $s^2=\int_\text{space min} (dt)^2-\left[(dx)^2+(dy)^2+(dz)^2\right]<0$. Two events in space-time are causally connected if their interval is time-like. Otherwise, they should not influence each other.

In an EPR experiment, a measurement is made at some point in space-time causally disconnected from the location of the other member of the pair (when describing the entangled pair as two particles). The way I understand the proposal in this thread, additional string dimensions should render ANY space-like interval into a time-like interval in order to remove ALL EPR-like paradoxes. However, additional dimensions in (conventional) string theories have space signature. They do not (usually) bring about another time dimension.

Is this thread suggesting that, in order to remove EPR-like paradoxes, one should consider several time dimensions ?

Last edited: Jan 7, 2009
9. Jan 7, 2009

### Demystifier

This idea does not really require strings, it only requires extra dimensions, which is good. Qualitatively, such an idea seems rather natural, which is also good. However, the problem is to construct a SIMPLE QUANTITATIVE model that contains exactly the same predictions (the correlations must be quantitatively the same) as quantum mechanics in 3+1 dimensions, including entanglement. No one has ever been able to construct such a model explicitly. Just saying that such a model could be constructed in principle is not enough.

10. Jan 7, 2009

### Saltlick

I think Yanniru is combining a couple of different ideas that could be treated separately. One idea is communication via extra dimensions, which leads to the time-like/space-like issue humanino stated. The other idea is the "stringy thread" connecting the electron/positron pair. If such a connection existed, and is assumed to be an actual material connection rather than a channel for messenger particles, then the dimensions thru which they are connected become irrelevant - they could be the normal 3+1d without any call to extra dimensions. What you're then positing instead is some non-local/superluminal connection via this "thread" that instaneously transmits information from the electron to the position (or vice versa).

Essentially you are theorizing that the electron/positron pair are really acting as a single particle that is extended over a macroscopic distance in 3+1d space, and that the apparent EPR causality violation is due to information traveling from one "end" of the extended particle to the other.

I don't know of anyone who's investigated this idea in any mathematically rigorous way, string-inspired or otherwise.

11. Jan 8, 2009

### Demystifier

It would not work for several reasons. First, it would not be consistent with the usual string theory, where particles are not the ends of the strings, but strings themselves. In other words, one particle is a particular state of one string. Second, it could not explain entanglement between 3 or more particles. Third, even if 2 particles were connected by a string, it would still be a problem to explain why the information along the string travels instantaneously.

12. Jan 8, 2009

### MTd2

I'm sorry if I am totally offtopic here, maybe this is useless information, but this thread began was ressurected 2 days ago, given that its post #4 is from august 04, and the first post is 5 years old... Maybe the guy changed his mind.

13. May 7, 2010

### unusualname

This is a perfectly reasonable suggestion if you allow that the "signal" transmitted between the particles in the extra dimension(s) is not allowed to influence anything beyond the observations we see in entanglement.

So special relativity is not broken since you can't transmit useful information.

Or, alternatively, the "signal" is something spooky not understood by current science, which doesn't interact with matter by any known mechanism (and not restricted by SR) eg consciousness interacting with brain matter.

Incidentally, entanglement doesn't require instantaneous transmission of the signal, just faster than the speed of light.

It seems perfectly reasonable that a "signal" could wind around a kaluza-klein type coiled extra dimension at speeds of order c to some sufficently high power (for example)

After all, Bell's theorem has only been tested over a few kilometers, it's a guess in popular expositions that the same entanglement behaviour would be seen over light year separations, which does seem a little crazy doesn't it? ;)

14. May 12, 2010

### Noja888

Although I am not a mathematician (trig and classical mechanics at best) I agree that entanglement could be explained though the extra dimensions of String Theory. If these extra dimensions are everywhere - yet small - this would provide a method of transferring information across vast 3D space and seem instantaneous to an observer (observing an event in 3D). I do not think you would need another time dimension, but I could not rule one out.