Bell's Proof and String Theory

[jasonchild]

I was wondering if anyone had some insight into how String Theory (or its derivations such as M Theory) deal with Bell's Proof of non-locality. From what I understand Bell states (indirectly) that underlying reality MUST be non-local in nature. His disproving of the EPR experimental findings shows as much (in regards to a two quon system anyhow). Heh, the very notion of the EPR findings does fly in the face of relational theory anyhow. How does string theory address/explain phase entanglement over large distances? Not with faster-than-light messenger particles, correct?

 

Pardon my poor grasp of these topics. I am a physics newbie and a mathematical moron.

 

regards,

 

jCc

[Erasmus00]

I was wondering if anyone had some insight into how String Theory (or its derivations such as M Theory) deal with Bell's Proof of non-locality. From what I understand Bell states (indirectly) that underlying reality MUST be non-local in nature. His disproving of the EPR experimental findings shows as much (in regards to a two quon system anyhow). Heh, the very notion of the EPR findings does fly in the face of relational theory anyhow. How does string theory address/explain phase entanglement over large distances? Not with faster-than-light messenger particles, correct?

 

Pardon my poor grasp of these topics. I am a physics newbie and a mathematical moron.

 

regards,

 

jCc

 

As I've stated in another thread, I'm not astrophysicist. But the idea of Bell's theorem is that there are no hidden variables underlying quantum mechanics. This means, as you said, reality is non-local. Also, it has since been suggested that the EPR paradox isn't actually a problem with relativity, because you cannot communicate information faster then light. Many worlders point to decoherence in hilbert space as both the mechanism for quantum's "spooky action at a distance" and as support for the many worlds quantum interpretation (if you want more on this, let me know.)

Now, as for the meat of your post, string theory. String theory does not attempt to explain entanglement effects, it is attempting to explain gravitational effects in a way that incorporates quantum effects, like uncertainty and entanglement. As such, it doesn't really postulate a mechanism for non-locality, just takes its existance as a given.

-Will

[jasonchild]

As I've stated in another thread, I'm not astrophysicist. But the idea of Bell's theorem is that there are no hidden variables underlying quantum mechanics. This means, as you said, reality is non-local. Also, it has since been suggested that the EPR paradox isn't actually a problem with relativity, because you cannot communicate information faster then light. Many worlders point to decoherence in hilbert space as both the mechanism for quantum's "spooky action at a distance" and as support for the many worlds quantum interpretation (if you want more on this, let me know.)

 

More info on the "Many Worlds" interpretation of QM would be quite nice indeed.

 

Now, as for the meat of your post, string theory. String theory does not attempt to explain entanglement effects, it is attempting to explain gravitational effects in a way that incorporates quantum effects, like uncertainty and entanglement. As such, it doesn't really postulate a mechanism for non-locality, just takes its existance as a given.

-Will

 

Thanks for the feedback.

 

It is interesting that string theory takes non-locality as a given. From what little I do know of string theory it not only tries to explain gravitational forces on a quantum level, but also goes a step beyond in doing so; identifying "primary constituents", or strings, as the "base block" of all particles. Given such then all "elementary particles" (quarks, quons, psions, etc) are no more than strings with variable vibrational patterns, no? This leads me to some (basic) questions regarding string theory:

 

* How does the vibrational pattern of a string effect the patterns of those around them? But with a non-locality view wouldnt ALL string's vibrational patterns contribute to what one could call a "Universal Harmonic"?

 

* I have read a little bit on the topics of "branes" and find it quite interesting. I fail to see how they are tied to string explicitly, however. Could someone help me out (links, etc)?

 

Thanks for the info, and for humoring my queries.

 

jCc

[Turtle]

* How does the vibrational pattern of a string effect the patterns of those around them? But with a non-locality view wouldnt ALL string's vibrational patterns contribute to what one could call a "Universal Harmonic"?

 

* I have read a little bit on the topics of "branes" and find it quite interesting. I fail to see how they are tied to string explicitly, however. Could someone help me out (links, etc)?

 

Thanks for the info, and for humoring my queries.

 

jCc

 

___I'm rather a novice on string theory & less so on non-locality, but I read Greene's book "Elegant Universe" by Brian Greene) a couple years back so I'll take a stab at a couple of your questions.

___In regard to how strings interact vibrationally, I gather it varies widely & that this is much of the high math in regard to topology & the super-symmetry of Calibi-Yau (sp) shapes. In general, they join up into different formations, as you said quarks etc., or they don't join up.

___In regard to the M branes, I seem to recall that mathematically treating the string as a rolled up sheet helps simplify or clarify some aspects of the general theory.

___Well, that's off the cuff & no doubt corrections follow as necessary. I do recommend Greene's book; I also have listened to him on late night talk radio a couple of times, taking calls & lecturing for 3 hours.

___I trust this is more help than harm. :cup:

[jasonchild]

___I'm rather a novice on string theory & less so on non-locality, but I read Greene's book "Elegant Universe" by Brian Greene) a couple years back so I'll take a stab at a couple of your questions.

___In regard to how strings interact vibrationally, I gather it varies widely & that this is much of the high math in regard to topology & the super-symmetry of Calibi-Yau (sp) shapes. In general, they join up into different formations, as you said quarks etc., or they don't join up.

___In regard to the M branes, I seem to recall that mathematically treating the string as a rolled up sheet helps simplify or clarify some aspects of the general theory.

___Well, that's off the cuff & no doubt corrections follow as necessary. I do recommend Greene's book; I also have listened to him on late night talk radio a couple of times, taking calls & lecturing for 3 hours.

___I trust this is more help than harm. :cup:

 

Thanks for the info. I have Greene's Fabric of the Cosmos, which really launched my interest in quantum mechanics, string theory and related topics. I will purchase The Elegant Universe on my next romp through the local bookstore (said romps are becomming more frequent these days...).

 

regards,

 

jCc

[geistkiesel]

As I've stated in another thread, I'm not astrophysicist. But the idea of Bell's theorem is that there are no hidden variables underlying quantum mechanics. This means, as you said, reality is non-local. Also, it has since been suggested that the EPR paradox isn't actually a problem with relativity, because you cannot communicate information faster then light. Many worlders point to decoherence in hilbert space as both the mechanism for quantum's "spooky action at a distance" and as support for the many worlds quantum interpretation (if you want more on this, let me know.)

Now, as for the meat of your post, string theory. String theory does not attempt to explain entanglement effects, it is attempting to explain gravitational effects in a way that incorporates quantum effects, like uncertainty and entanglement. As such, it doesn't really postulate a mechanism for non-locality, just takes its existance as a given.

-Will

Erasamus00,

Excuse me for nit-picking here but is not Bell's theorem that there are no

local

hidden variables underlying qm? And that the reaility is that hidden variables must be nonlocal. Bell also made the finding that any QM model that was void in nonlocal force structures is an incomplete model.

 

Also, I am slightly confused somewhat by your statement,

 

"EPR paradox isn't actually a problem with relativity, because you cannot communicate information faster then light."

 

I understand that the EPR experiments (much after Einsteins EPR publication, i.e. Clausen et al) found "instantaneous" communication that must have occured nonlocally and it is for this reason that relativity is not a problem. In other words, because the "information" does not travel in space-time where relativity is confined [to] that there is no contradiction?

 

Reading your total response I assumed you incorporated "nonlocality" into your statement re EPR. Again, 'scuse the nitpicking.

 

Finally, Bell published a book of his papers on the subject, "Speakable and unspeakable in quantum mechanics". Even for the mathematical poor student, the book is a gold mine into understanding "nonlocality", at least is was for me. I always get siomething new everytime I read it.

 

 

BTW Erasmus00, are you familiar with Stern-Gerlach transition of spin-1 particles on the level seen in Feynman's, "Lectures on Physics" Vol. III, ch 5? If so I have a couple of matters i would like to discuss.

Geistkiesel.

[Qfwfq]

The topic is not simple at all. Here is a good source, Abner Shimony is very competent on the subject.

 

http://plato.stanford.edu/entries/bell-theorem/

[Erasmus00]

I understand that the EPR experiments (much after Einsteins EPR publication, i.e. Clausen et al) found "instantaneous" communication that must have occured nonlocally and it is for this reason that relativity is not a problem. In other words, because the "information" does not travel in space-time where relativity is confined [to] that there is no contradiction?

 

You are right, there are no local hidden variables, according to Bell. In the EPR experiment, two particles become entangled, two people make measurements and they always agree. So one particle must "communicate" what state it was measured in faster than light. However, this can't actually be used to send information between two people. If I want to send my buddy a signal, I'd need some way of influencing what my measurement outcome would be (say spin up, or spin down). But I can't influence the particle and still keep the two entangled. Hence, no information can be transfered faster than light.

 

BTW Erasmus00, are you familiar with Stern-Gerlach transition of spin-1 particles on the level seen in Feynman's, "Lectures on Physics" Vol. III, ch 5? If so I have a couple of matters i would like to discuss.

Geistkiesel.[/indent]

 

I'm not familiar with the Feynman specifically, but I have an understanding of the Stern Gerlach experiment, and particle spin at an above introductory level. I'm sure there are others here who do as well.

-Will

[UncleAl]

Bell's Inequalty and the Einstein-Podolsky-Rosen paradox disprove nothing. Wavefunction collapse into an observable is empirically instantaneous across arbitrarily large distances and volumes. However, it cannot transmit information - not even Morse code. Remotely collected a data is utterly random until compared with the sender's results, and that can comparison can proceed no faster than lightspeed. Both Relativity and quantum mechanics emerge intact and unaltered.

 

M-theory is 100% non-predictive. It has no accessible experimental falsification.

[geistkiesel]

You are right, there are no local hidden variables, according to Bell. In the EPR experiment, two particles become entangled, two people make measurements and they always agree. So one particle must "communicate" what state it was measured in faster than light. However, this can't actually be used to send information between two people. If I want to send my buddy a signal, I'd need some way of influencing what my measurement outcome would be (say spin up, or spin down). But I can't influence the particle and still keep the two entangled. Hence, no information can be transfered faster than light. .

-Will

Erasmus00,

Theoretically I think that information can be sent "nonlocally". The problem, at least how I see it, is in delivering the particle to the distant receiver. The particle that is being affected distantly can travel only at (approx.) the speed of light, but the particle can be affected instantaneously from a distance. If batches of entangled particles could be delivered distantly and were the sender able to maintain a storehouse of the distant partilces twin, then the instantaneous transfer of information could have some practical use.

The "batches" of entanled particles does leave a substantial technical problem to be solved however. This would require an earthling travelling at a distance to carry a "batch" of entangled twins along with her space ship. Boiling things down, how would one create a batch of entangled twins as well as the necessary storehouse without subjecting the particles to a "measurement" until a message was constructed?

Geistkiesel

[Erasmus00]

Erasmus00,

Theoretically I think that information can be sent "nonlocally". The problem, at least how I see it, is in delivering the particle to the distant receiver. The particle that is being affected distantly can travel only at (approx.) the speed of light, but the particle can be affected instantaneously from a distance. If batches of entangled particles could be delivered distantly and were the sender able to maintain a storehouse of the distant partilces twin, then the instantaneous transfer of information could have some practical use.

The "batches" of entanled particles does leave a substantial technical problem to be solved however. This would require an earthling travelling at a distance to carry a "batch" of entangled twins along with her space ship. Boiling things down, how would one create a batch of entangled twins as well as the necessary storehouse without subjecting the particles to a "measurement" until a message was constructed?

Geistkiesel

 

Even if you could create entangled twins and ship them, how would you transmit any information with them? You can only measure the particles, you can't influence the outcomes.

-Will

[geistkiesel]

Even if you could create entangled twins and ship them, how would you transmit any information with them? You can only measure the particles, you can't influence the outcomes.

-Will

Will, Only by being able to distinguish between particles in the batch that had been measured could a coded message be sent.

 

Lets say that the sender measurement device is oriented in one direction, say up. The batch of paricles he will be measuring then will only measure up implying that the measured distance twin would immediately measure down. Then by prearrangement one million down measurements followed by a pause and 5 million more down followed by a pause etc then a message could be sent. on the basis of violating statistical expected measurements. Again, the scheme would work only if sender and receiver could accumulate batches of separated twins, which I see is not a trivial process, even if theoretically possible.

Geistkiesel

[Erasmus00]

Will, Only by being able to distinguish between particles in the batch that had been measured could a coded message be sent.

 

Lets say that the sender measurement device is oriented in one direction, say up. The batch of paricles he will be measuring then will only measure up implying that the measured distance twin would immediately measure down. Then by prearrangement one million down measurements followed by a pause and 5 million more down followed by a pause etc then a message could be sent. on the basis of violating statistical expected measurements. Again, the scheme would work only if sender and receiver could accumulate batches of separated twins, which I see is not a trivial process, even if theoretically possible.

Geistkiesel

 

If you have a device that only measures "up" spins, then half the time, you'll measure an up, and half you won't measure anything (assuming your entangled state is such that psi = 1/sqrt2(up+down)). Because a down spin wouldn't register in your up spin measuring device. Your opposite, trying to recieve your message, will also see half spin downs and half spin ups. He has no way of knowing what you intended to send.

-Will

[Qfwfq]

Bell's Inequalty and the Einstein-Podolsky-Rosen paradox disprove nothing.

The violation of Bell's Inequalty does prove something, providing the detection and comunication loopholes can be closed.

 

Both Relativity and quantum mechanics emerge intact and unaltered.

QM emerges intact because the inequalities are violated, rather than the predictions of QM with which the data agree quite well. There are details of this in Abner Shimony's paper that I linked to.

 

Uncle Al, your pontificating attitude would be less out of place if everything you said were always correct.

[Little Bang]

To me Stern-Gerlack says that the observer sees what the observer decides to see. of course that's only my opinion.

[geistkiesel]

If you have a device that only measures "up" spins, then half the time, you'll measure an up, and half you won't measure anything (assuming your entangled state is such that psi = 1/sqrt2(up+down)). Because a down spin wouldn't register in your up spin measuring device. Your opposite, trying to recieve your message, will also see half spin downs and half spin ups. He has no way of knowing what you intended to send.

-Will

Will, I will concede the point. I think this thread wrt you and I will not produce anything useful. I do not disagree with anything you have said so far , in fact i agree with what you have been arguing. I was merely probing for some hidden path that would provide a way to use the EPR experimental results for practical application. I didn't find any, nor have I discovered any clues that would provide a direction for maintaining this thread as it has been moving so far.

 

However, having said that I will post a thread re Stern-Gerlach that should prove to be a bit more energetic as a topic of discussion.

 

Geistkiesel ;)

[bumab]

To me Stern-Gerlack says that the observer sees what the observer decides to see. of course that's only my opinion.

 

...and that's funny.